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Abstract

Background:

With ageing world populations, multimorbidity (presence of two or more chronic diseases in the same individual) becomes a major concern in public health. Although multimorbidity is associated with age, its prevalence varies. This systematic review aimed to summarise and meta-analyse the prevalence of multimorbidity in high, low- and middle-income countries (HICs and LMICs).

Methods:

Studies were identified by searching electronic databases (Medline, Embase, PsycINFO, Global Health, Web of Science and Cochrane Library). The term ‘multimorbidity’ and its various spellings were used, alongside ‘prevalence’ or ‘epidemiology’. Quality assessment employed the Newcastle-Ottawa scale. Overall and stratified analyses according to multimorbidity operational definitions, HICs/LMICs status, gender and age were performed. A random-effects model for meta-analysis was used.

Results:

Seventy community-based studies (conducted in 18 HICs and 31 LMICs) were included in the final sample. Sample sizes ranged from 264 to 162,464. The overall pooled prevalence of multimorbidity was 33.1% (95% confidence interval (CI): 30.0–36.3%). There was a considerable difference in the pooled estimates between HICs and LMICs, with prevalence being 37.9% (95% CI: 32.5–43.4%) and 29.7% (26.4–33.0%), respectively. Heterogeneity across studies was high for both overall and stratified analyses (I ² > 99%). A sensitivity analysis showed that none of the reviewed studies skewed the overall pooled estimates.

Conclusion:

A large proportion of the global population, especially those aged 65+, is affected by multimorbidity. To allow accurate estimations of disease burden, and effective disease management and resources distribution, a standardised operationalisation of multimorbidity is needed.

Keywords

Multimorbidity prevalence HICs LMICs

Introduction

As the world’s populations are ageing rapidly, multimorbidity is becoming a major concern in public health. According to a recent report by the Academy of Medical Science,¹ in most high-income countries (HICs), multimorbidity is considered the norm, not the exception. Multimorbidity also appears to be increasingly prevalent in low- and middle-income countries (LMICs).¹ Patients experiencing multiple chronic conditions often have poorer health outcomes, such as declined physical and mental health functioning,² higher mortality rates³ and frailty.⁴ Their needs for medical care are also different. Instead of a highly specialised but isolated approach, as used for single disease treatment, multimorbidity patients need a complex and structured care plan.^1,5 This has serious impact on disease management, healthcare utilisation and costs.^6
–8 To assess the impact of multimorbidity on public health and to project medical care needs for patients with multimorbidity, an accurate estimation of its prevalence is critical. Yet, the complex nature of multimorbidity poses great difficulties for research into this topic area. This is due partly to inconsistencies in the conceptualisation and definition of multimorbidity. For instance, despite being distinct clinical entities, multimorbidity and comorbidity are still used interchangeably. While the former is defined as the co-occurrence of two or more chronic diseases, the latter is perceived as ‘the occurrence of medical conditions additional to an index disease’.⁹ The ambiguity in the conceptualisation of multimorbidity leads to a lack of a consensus about its operationalisation. The number of diseases used as cut-off points, disease combination and measure of multimorbidity vary across studies.

Although multimorbidity prevalence and its variations have been examined and summarised in a number of systematic reviews,^10,11 these reviews usually only included studies in HICs. Only one review synthesised evidence on the prevalence and outcomes of multimorbidity in South Asia.¹² Nonetheless, there has not been a review that systematically assessed the variations of multimorbidity prevalence estimates at a global level. Our aims were therefore to (1) summarise the available evidence in the literature on the global prevalence of multimorbidity in the context of community settings, (2) carry out a meta-analysis of the prevalence estimates to provide a pooled estimate and (3) assess how multimorbidity was operationalised across the different studies to examine whether this factor could explain the heterogeneity of the prevalence estimates.

Methods

We conducted a systematic review and meta-analysis (registered on PROSPERO Ref no. CRD42018087435), which followed the PRISMA statement for systematic review and analysis¹³ (Online Supplement 1).

Inclusion and exclusion criteria

Eligible studies were original, peer-reviewed articles (published either online or as hard copy, with available abstracts in English). Opinion pieces, conference presentations, books, letters, editorials, dissertations/theses or abstracts were not included. Studies with an index disease (e.g. multimorbidity among HIV-infected individuals) were also not eligible for inclusion, because they were deemed comorbidity studies. Only studies that clearly stated that their participants were community-based adults were considered. In other words, studies that recruited participants from communal establishments, such as hospitals, hospices, nursing homes or prisons, were ineligible. Those that used solely medical records from general practice as data source were also excluded to avoid selection bias. The study designs were restricted to cross-sectional and longitudinal studies. Where the design was longitudinal, only prevalence at baseline was included. Case-control and interventional studies (such as randomised controlled trials) were removed from consideration. There were no further restrictions regarding demographic characteristics of the population under study, for instance, age, sex, or socioeconomic status. Since the outcome of interest was the prevalence of multimorbidity, only studies that reported on this were selected.

Search strategy and study selection

We conducted an online literature search on Medline (Ovid interface), Embase (Ovid interface), PsycINFO (Ovid interface), Global Health (Ovid interface), Web of Science and Cochrane Library electronic databases, from inception up to May 2019. The term ‘multimorbidity’ and its various spellings (e.g. ‘multi-morbidity’, ‘multimorbidities’, ‘multi-morbidities’, ‘multi morbidity’, ‘multi morbidities’, ‘multiple morbidities’, ‘multiple-morbidities’) and ‘prevalence’ or ‘epidemiology’ were used (Online Supplement 2). We were interested in how multimorbidity was defined so deliberately excluded ‘comorbidity’ and other synonyms in our search strategy.

The titles and abstracts of all hits returned by the search were screened initially by the first reviewer (HN). The second reviewer (CD) tested a 10% random sample of all references to ensure that eligible studies were not missed out. Studies that satisfied all the eligibility criteria specified above were kept for full-text screening. The full-text screening was done independently by two reviewers (HN and GM). Where there were disagreements, HN and GM discussed to resolve them. AMP was consulted when agreement could not be reached. Disagreements were finally resolved by consensus.

Data extraction and quality assessment

We extracted all potentially eligible studies to EndNote (EndNote X8, Thomson Reuters). Duplicate articles were removed using EndNote X8 auto-deduplication function. Those that were not detected by this function were removed manually during the first screening.

A data extraction sheet was developed, pilot-tested on five randomly selected eligible studies and refined accordingly. We extracted the following information: year of study, study design, country of study, data source, sample size, mean age (men/women), definition of multimorbidity, measure of multimorbidity, prevalence of multimorbidity, number of diseases, ascertainment of diseases and combination of diseases. In case this information could not be retrieved from the included studies, the corresponding authors of such studies were contacted. Six authors were contacted and three provided the requested information.

We adopted the age-related adjustment method developed by Fortin et al¹¹ to enable comparisons of age-specific prevalence across studies. If prevalence was reported for an age range, we calculated mean age between the lower and upper limits to present that range.¹¹ If prevalence was reported for an age range with an upper or lower limit only, we adjusted the age to 10 years above the lower limit and 10 years below the upper limit.¹¹ Exception of this rule was when the prevalence was reported for age groups such as 65+ or 75+, we used this prevalence without making any age adjustments.

To assess the risk of bias for individual studies, the Newcastle-Ottawa Scale (NOS) for assessing the quality of non-randomised studies was used. NOS uses eight items, categorised into three domains of potential bias, namely selection (representativeness of the sample, sample size, non-respondents, ascertainment of the exposure), comparability (the subjects in different outcome groups are comparable, based on the study design or analysis; and confounding factors are controlled) and outcome (assessment of outcome and statistical test).¹⁴ A study can be given a maximum of one star for each item within the selection and outcome categories. A maximum of two stars can be given for comparability. Thresholds for converting the NOS to Agency for Healthcare Research and Quality standards (good, fair and poor)¹⁵ are as follows:

Good quality: 3 or 4 stars in selection domain AND 1 or 2 stars in comparability domain AND 2 or 3 stars in outcome/exposure domain

Fair quality: 2 stars in selection domain AND 1 or 2 stars in comparability domain AND 2 or 3 stars in outcome/exposure domain

Poor quality: 0 or 1 star in selection domain OR 0 star in comparability domain OR 0 or 1 star in outcome/exposure domain.

Eligible studies after full-text screening were assessed (Online Supplement 3). Both good and poor quality studies were retained for sensitivity analysis at a later stage.

Data analysis

Overall and stratified analyses according to multimorbidity operational definitions (2+ and 3+ diseases cut-off points) and HIC–LMIC status were performed. HICs and LMICs were determined using the World Bank classification list of economies.¹⁶ Where possible, prevalence of multimorbidity was also stratified by age and gender. Studies that reported multimorbidity prevalence, both standardised and non-standardised, using the 2+ chronic diseases cut-off point as definition, were included in the meta-analysis. To perform the meta-analysis, we used the metaprop command.¹⁷ Multimorbidity prevalence was calculated as the quotient of the number of people with multimorbidity (numerator) and sample size (denominator). Where not available, the numerator was converted from the percentage of people with multimorbidity. Using absolute numbers to generate prevalence estimates enabled the calculation of standard error. Heterogeneity across studies was evaluated using I ² statistic.¹⁸ It was expected that the I ² statistic would be high, due to the heterogeneous operationalisation of multimorbidity. Hence, a random-effects model was used. Finally, a sensitivity analysis was carried out to test the influence of a single study in meta-analysis estimation of the pooled prevalence. All quantitative synthesis of this review was done in STATA version 15.¹⁹

Results

Overview of studies

We identified 4360 studies from the initial search. After removing duplicates and records that were not original articles, there were 274 studies eligible for full-text screening. Two hundred four studies were further excluded after full-text screening, leaving 70 for final qualitative and quantitative synthesis. The PRISMA flow diagram in Figure 1 shows the exact process of studies selection.

Figure 1.

PRISMA flow diagram of studies selection.

Study quality and characteristics

Based on the NOS data quality assessment system, 63 studies were rated good quality (with a score of 6 or 7), 2 studies were rated fair quality (with a score of 5) and 5 studies were rated poor quality (with a score of 2 or 4). Those deemed poor quality were so because they omitted information about the representativeness of their data, sampling strategy or response rates (see Online Supplement 3). The total number of participants across 70 studies was 1,180,111 (men: 47.5%, women: 52.5%), with sample size ranging from 264 to 162,464. The mean age varied between 36 years and 75 years old. Thirty-seven studies were conducted in HICs (5 in Australia,^20

–24 4 in Canada,^25

–28 4 in Spain,^29

–32 3 in Germany,^33
–35 3 in Portugal,^36
–38 3 in the United Kingdom,^39
–41 3 in Hong Kong,^42
–44 2 in Singapore,^45,46 2 in the United States^47,48 and 1 each in Cyprus,⁴⁹ Czech Republic,²⁹ Denmark,⁵⁰ Estonia,²⁹ Finland,³⁰ France,⁵¹ Hungary,²⁹ Latvia,²⁹ Poland,³⁰ Ireland,⁵² South Korea,⁵³ the Netherlands,⁵⁴ Sweden⁵⁵ and Switzerland⁵⁶) and 35 in LMICs (9 in China,^{30,57

–64} 8 in India,^{30,65

–71} 10 in Brazil,^{29,72

–80} 3 in South Africa,^29,30,81 2 in Ghana,^29,30 2 in Pakistan,^29,71 2 in Bangladesh,^29,82 2 in Burkina Faso,^29,83 and 1 each in Bosnia and Herzegovina,²⁹ Colombia,⁸⁴ Dominican Republic,²⁹ Egypt,⁸⁵ Georgia,²⁹ Iran,⁸⁶ Kazakhstan,²⁹ Kenya,²⁹ Kosovo,⁸⁷ Laos,²⁹ Malaysia,²⁹ Mauritius,²⁹ Mexico,³⁰ Morocco,²⁹ Myanmar,²⁹ Namibia,²⁹ Nepal,²⁹ Paraguay,²⁹ the Philippines,²⁹ Russia,³⁰ Serbia,⁸⁸ Sri Lanka,²⁹ Ukraine,²⁹ Uruguay²⁹ and Vietnam⁸⁹) over a period of 25 years, from 1992 to 2017. Most of them (63 studies) were cross-sectional design, and seven^{21,23,39,43,54,57,60} had a longitudinal design, from which we used data from the baseline assessment. Only 5 out of 70^{22,47,75,76,80} studies focused solely on subgroups of either men or women. The number of diseases included in eligible studies ranged from 4 to 40 (with hypertension, diabetes, arthritis and stroke being four most frequent conditions). Disease count was the most common measure of multimorbidity, based on self-reported data. Details of studies’ characteristics are provided in Table 1.

Table 1.

Characteristics of included studies.^a

Study (country of study)	Data collection period	Data source	Sample size	Age	Gender (% men)	Prevalence (%) (95% CI)
Afshar 2015 (28 countries)	2003	WHO World Health Survey	125404	18+	48.5	7.8 (6.5–9.1)
Agborsangaya 2013 (Canada)	2012	Health Quality Council of Alberta (HQCA) 2012 Patient Experience Survey	4803	18+	44.2	36.1 (34.7–37.3)
Alaba 2013 (South Africa)	2008	South Africa National Income Dynamic Survey (SA-NIDS)	11638	18+	39.0	4.0 (3.6–4.4)
Alimohammadian 2018 (Iran)	2004–2008	Golestan Cohort Study (GCS)	49946	40–75	42.4	19.4 (19.1–19.8)
Amaral 2018 (Brazil)	2010	Population-based study	264	60–102	39.0	66.3 (60.4–71.7)
Araujo 2018 (Brazil)	2015	Population-based study	4001	60+	47.2	29.0 (27.6–30.5)
Banjare 2014 (India)	2011–2012	Cross-sectional survey	310	60+	49.4	56.8 (51.2–62.2)
Buttery 2016 (Germany)	1997–1999	German National Health Interview and Examination Survey 1998 (GNHIES98)	2884	50–79	47.6	M: 36.1 (33.6–38.7) F: 40.5 (38.1–43.0)
Camargo-Casas 2018 (Colombia)	2012	The SABE-B study	2000	60+	36.6	40.4 (38.3–42.6)
Chen 2018 (China)	2011	China Health and Retirement Longitudinal Study (CHARLS)	3737	45+	51.9	45.5 (41.4–49.7)
Cheung 2018 (Hong Kong)	2016–2017	Jockey Club Community eHealth Care project	2618	60+	47.5	41.8 (39.9–43.7)
de Carvalho 2017 (Brazil)	2013	National Health Survey	60202	18+	N/A	23.6 (22.9–24.3)
de Souza Santos Machado 2012 (Brazil)	2005	Population-based study	377	40–65	Women only	39.3 (34.5–44.3)
de Souza Santos Machado 2013 (Brazil)	2011	Population-based study	622	50+	Women only	58.2 (54.3–62.0)
Dhawalni 2016 (England)	2002–2003	English Longitudinal Study of Ageing (ELSA)	11212	50+	46.4	31.7 (30.9–32.6)
El Lawindi 2019 (Egypt)	2016–2017	Community-based study	2317	18–85	54.9	19.6 (18.0–21.3)
Fuchs 2012 (Germany)	2008–2009	German Health Update (GEDA)	21262	18–100	48.5	M: 36.3 (35.4–37.2) F: 43.9 (43.0–44.8)
Garin 2016 (9 countries)	2008–2012	WHO study on Global AGEing and Adult Health (SAGE) and the Collaborative Research on Ageing in Europe (COURAGE) survey	41909	50+	46.5	62.7 (55.2–70.1)
Ge 2018 (Singapore)	2015–2016	The Population Health Index Survey	1940	21+	44.3	36.9 (34.7–39.0)
Gu 2017 (China)	2013	Cluster random sampling survey	2452	60–93	51.5	49.4 (47.4–51.4)
Hameed 2015 (India)	2013	Community-based study	375	60+	57.9	79.4 (75.1–83.3)
Hien 2014 (Burkina Farso)	2012	Cluster random sampling survey	389	60+	55.3	65.0 (59.9–69.4)
Humphreys 2018 (UK)	2007–2008	The Hertfordshire Cohort study	2299	64–68	51.0	43.4 (41.4–45.5)
Islam 2014 (Australia)	2009	Stratified random sampling survey	4574	50+	N/A	52.0 (50.5–53.4)
Jankovic 2018 (Serbia)	2013	2013 Serbian National Health Survey	13765	20+	46.0	30.2 (29.4–30.9)
Jerliu 2013 (Kosovo)	2011	Nationwide cross-sectional study	1890	65+	50.2	51.1 (48.8–53.3)
Johnston 2019 (UK)	2001	The Aberdeen Children of the 1950s (ACONF)	7184	50+	47.7	5.4 (4.9–6.0)
Khanam 2011 (Bangladesh)	2003–2004	Poverty and Health in Ageing study	452	60–92	45.1	53.7 (49.2–58.3)
Kiliari 2014 (Cyprus)	2008	Nationally based survey	465	N/A	43.2	28.5 (24.7–32.9)
Kirchberger 2012 (Germany)	2008–2009	KORA-AGE study	4127	65–94	48.8	58.6 (50.7–60.2)
Kshipra 2018 (India)	2012–2013	Cross-sectional study	400	50+	N/A	31.0 (26.7–35.7)
Kumar 2015 (India)	2012–2013	Household survey	55091	N/A	52.3	0.7 (0.6–0.7)
Lai 2019 (Hong Kong)	1999	Thematic Household Survey (THS)	17229	35+	49.5	3.5 (3.2–3.8)
Laires 2019 (Portugal)	2014	The Portuguese National Health Interview Survey (Inquerito Nacional de Saude, INS)	15196	25–79	44.0	43.9 (43.1–44.7)
Lalitha 2016 (India)	2009	Household survey	815	40+	51.3	44.1 (40.6–47.5)
Lang 2015 (US)	2012–2013	EuroQol 5 dimensions (EQ-5D) study	3058	40–64	Women only	30.6 (29.0–32.3)
Larsen 2017 (Denmark)	2013	Danish National Health Survey	162283	16+	49.0	39.7 (39.4–39.9)
Le Cossec 2016 (France)	2008	Disability Healthcare Household Section Survey (HSM – Enquete Handicap Sante - Menages)	11089	55+	45.1	M: 18.7 (17.6–19.9) F: 15.2 (14.3–16.1)
Li 2019 (China)	2017	Community-based survey	4833	60+	45.5	16.1 (15.1–17.1)
Loprinzi 2015 (US)	2005–2006	2005–2006 National Health and Nutrition Examination Survey (NHANES)	2048	20+	50.9	58.4 (55.3–61.5)
Loza 2009 (Spain)	1999–2000	EPISER study	2192	N/A	N/A	30.0 (25.0–34.0)
Lujic 2017 (Australia)	2005–2009	45 and up study	90352	45+	44.3	37.4 (37.1–37.7)
Maregoni 2016 (Sweden)	2001–2004	Swedish National Study on Ageing and Care in Kungsholmen (SNAC-K)	3155	60+	35.7	52.4 (50.6–54.2)
Mini 2017 (India)	2011	UNFPA funded national survey	9852	60+	47.0	30.7 (29.8–31.6)
Ninh 2015 (Vietnam)	2010	Population-based study	2400	60+	34.8	41.6 (39.5–43.8)
Noguchi 2016 (Australia)	2005–2007	Concord Health and Ageing in Men Project (CHAMP)	1705	70–99	100.0	69.3 (67.1–71.5)
Nunes 2016 (Brazil)	2012	Population-based cross-sectional study	2927	20+	41.1	29.1 (27.1–31.1)
Nunes 2019 (Brazil)	2015–2016	The Brazilian Longitudinal Study of Ageing (ELSI-Brazil)	9412	50+	46.0	67.8 (65.6–69.9)
Nunes 2015 (Brazil)	2008	Population-based survey	1593	60+	37.2	81.3 (79.3–83.3)
Pache 2015 (Switzerland)	2003–2006	Cohorte Lausannoise (CoLaus) study	3714	35–75	47.0	34.8 (33.3–36.4)
Park 2018 (Korea)	2013–2014	The sixth Korean National Health and Nutritional Examination Survey (KNHANES)	5996	50+	46.6	26.8 (25.7–27.9)
Picco 2016 (Singapore)	2012–2013	Well-being of the Singapore Elderly (WiSE) study	2565	50+	N/A	55.4 (53.4–57.3)
Ramond-Roquin 2016 (Canada)	2010	PRECISE study	1710	18+	48.3	63.8 (61.5–6.1)
Roberts 2015 (Canada)	2011–2012	Canadian Community Health Survey (CCHS)	105416	25–75	40.5	12.9 (12.6–13.2)
Rodrigues 2018 (Portugal)	2013–2015	EpiDoc 2 study	2393	65+	44.2	67.9 (66.0–9.7)
Romana 2019 (Portugal)	2015	Inquerito Nacional de Saude com Exame Fisico (INSEF)	4911	25–74	47.5	38.4 (37.0–39.8)
Ruel 2014 (Australia)	2000–2002	North West Adelaide longitudinal Health Study (NWAHS)	1854	20+	44.1	32.0 (30.0–4.0)
Ruel 2014 (China)	2002	Jiangsu longitudinal Nutrition Study (JIN)	1020	18+	48.0	14.0 (12.0–16.3)
Ryan 2018 (Ireland)	2010	The Irish Longitudinal Study on Ageing (TILDA)	4823	50+	N/A	53.7 (52.3–55.1)
Sakib 2019 (Canada)	2015	The Canadian Longitudinal Study of Ageing (CLSA)	29841	45–64	49.4	39.6 (38.4–40.7)
Singh 2019 (India and Pakistan)	2010–2011	The Cardiometabolic Risk Reduction in South Asia Surveillance Study (CARRS Surveillance Study)	16287	20+	47.3	9.4 (8.7–10.1)
Su 2016 (China)	2013	Multistage cluster study	2058	80+	42.1	49.2 (47.0–51.3)
Timmermans 2019 (the Netherlands)	1992–1993	The Longitudinal Ageing Study Amsterdam (LASA)	2199	64–84	44.9	43.6 (41.6–45.7)
Valadares 2015 (Brazil)	2012–2013	Cross-sectional study	736	45–60	Women only	53.0 (49.4–56.6)
Violan 2013 (Spain)	2006	Health Survey for Catalonia database 2006	15926	15+	49.5	59.6 (58.8–60.4)
Wang 2014 (China)	2011	Cross-sectional community household survey	162464	All	51.4	11.1 (10.6–11.6)
Wang 2017 (Australia)	2007	2007 Australian National Survey of Mental Health and Wellbeing	8841	16–85	49.7	28.7 (27.8–9.7)
Wang 2015 (China)	2010–2011	Confucious Hometown Aging Project (CHAP)	1480	60+	40.6	90.5 (88.9–91.9)
Wang 2015 (China)	2012	Jilin Provincial chronic Disease Survey	21435	18–79	N/A	24.7 (24.1–25.4)
Wong 2008 (Hong Kong, China)	N/A	Cross-sectional study	3394	65+	56.0	68.0 (66.4–9.5)

M: male; F: female; CI: confidence interval.

^a Multimorbidity was defined as the presence of two or more chronic diseases in the same individual; 95% CI as reported in original studies was presented in Table 1. Where this was not available, we used the 95% CI generated by STATA for the meta-analysis. For studies that investigated multimorbidity prevalence in several countries, the prevalence presented in Table 1 was the pooled country prevalence estimates.

Prevalence of multimorbidity

Among 37 nationally representative studies in HICs, one conducted in Hong Kong reported the lowest prevalence (3.5%)⁴³ while another conducted in Russia reported the highest prevalence (70%).³⁰ Of those that were conducted in LMICs, one study which used data from a household survey in 26 villages in India reported the lowest multimorbidity prevalence (1%).⁶⁸ Another study with data derived from the Confucius Hometown Project in China, on the contrary, reported the highest prevalence estimate (90%).⁶⁴

In addition to the common cut-off point of 2+ chronic diseases (2+MM) used in 68 studies, 20 studies also investigated the prevalence estimate when multimorbidity was defined as ‘the co-occurrence of three or more chronic diseases’. As the number of diseases included in the definition increased, the prevalence decreased (Table 2). The biggest difference was observed in Khanam et al.’s study,⁸² where the prevalence of 3+ morbidities (3+MM) was reported to be 19.5%, which represented a decrease of 34.3 percentage points compared to the prevalence of 2+ morbidities (53.8%). On average, the weighted difference between the prevalence of 2+MM and 3+MM was 12.9 percentage points.

Table 2.

Prevalence of multimorbidity by two or more diseases and three or more diseases cut-off points.

Study	2+ MM (%)	3+ MM (%)	Difference	Sample size
Araujo (2018)	29.0	15.2	13.8	4001
Banjare and Pradhan (2016)	56.8	30.0	26.8	310
Dhawalni (2016)	31.7	11.7	20.0	11212
Garin (2014)	9.7	5.4	4.3	4583
Humphreys (2018)	47.6	21.6	26.0	2299
Khanam (2011)	53.8	19.5	34.3	452
Lang (2015)	17.9	12.7	5.2	3058
Lujic (2017)	37.4	8.7	28.7	90352
Nunes (2016)	29.1	14.3	14.8	2927
Nunes (2019)	67.8	47.1	20.7	9412
Nunes (2015)	81.3	64.0	17.3	1593
Ramond-Roquin (2016)	63.8	48.9	14.9	1710
Roberts (2015)	12.9	3.9	9.0	105416
Ruel (2014)	32.0	9.0	23.0	1854
Su (2016)	49.2	18.5	30.7	2058
Wang (2014)	11.1	6.1	5.0	162464
Wang (2015)	90.5	76.5	14.0	1480
Wang (2015)	24.8	12.0	12.8	21430
Wang (2017)	26.0	10.1	15.9	8820
Wong (2008)	68.0	42.4	25.6	3394
Average difference		18.4
Weighted average difference		12.9

2+MM: two or more disease cut-off point; 3+MM: three or more disease cut-off point.

Among 25 studies that explored gender variations, the majority (21 studies) reported a higher prevalence in women than in men. Alaba and Chola,⁸¹ in particular, found that multimorbidity was almost double in females (74% in females vs. 26% in males). The reverse trend was observed in only four studies.^51,65,67,68 Nevertheless, when men were reported to have higher multimorbidity prevalence, the differences in prevalence estimates between the two sexes were relatively small (Online Supplement 4). Figure 2 shows that the prevalence of multimorbidity invariably increased for both men and women as they aged. There was an upward trend, where multimorbidity prevalence was positively associated with age. Of nine studies that reported age–sex specific prevalence, Kirchberger et al.³⁵ found that the highest prevalence was in the 85+ group (men: 76.3%; women: 88.1%). Although this association was supported by 24 other studies that investigated age-specific prevalence, three studies observed a lower prevalence estimate among the oldest old (80–85 age group). Kiliari et al,⁴⁹ in particular, found that after the age of 85, the prevalence of multimorbidity in Cyprus decreased to 33.3% (from 80% in the previous age bracket). The highest prevalence estimate was reported for the 75+ age group in Spain (92.9%).³² The largest variation, with prevalence of multimorbidity ranging from 16.3% to 87.5%, was around the age of 70.

Figure 2.

Age- and sex-specific prevalence of multimorbidity.

Meta-analysis

Data combined from 106 prevalence estimates (from 68 studies) showed that the overall random-effect pooled prevalence of multimorbidity was 33.1% (95% CI): 30.0–36.3%). There was a considerable difference in the pooled prevalence estimates between HICs (44 estimates) and LMICs (62 estimates). Specifically, the pooled prevalence of multimorbidity among HICs was 37.9% (95% CI: 32.5–43.4%), while the pooled prevalence estimate among LMICs was 29.7% (26.4–33.0%; Figures 3(a) and (b), Online Supplement 5).

Figure 3.

(a) Forest plot showing multimorbidity prevalence in HICs. (b) Forest plot showing multimorbidity prevalence in LMICs. HIC: high-income country; LMIC: low-income country.

However, when standardised prevalence was removed (34 estimates), LMICs’ prevalence was found to be higher than that of HICs. This difference, nonetheless, was marginal, with HICs prevalence being 41.3% (95% CI: 35.2–47.4%) and LMICs 43.5% (95% CI: 38.4–48.6%). The overall pooled estimate of non-standardised prevalence rose to 42.4% (95% CI: 38.1–46.6%; Online Supplement 6). Heterogeneity across studies, both before and after adjusting for standardisation, was very high (I ² > 99%). A sensitivity analysis showed that none of the studies included in our review skewed the overall pooled estimates.

Discussion

This systematic review provides an up-to-date and comprehensive analysis of multimorbidity prevalence at a global level. It shows that prevalence estimates varied substantially according to age, gender and operational definitions of multimorbidity. This was due to wide variations in sample size, characteristics and how prevalence was reported across studies. Nevertheless, the main findings from our review were consistent with those in previous studies and systematic reviews.^10,90 Specifically, our data suggested that multimorbidity increases with age. While the prevalence estimates varied between and within age groups, most studies in our sample indicated that a large proportion (more than 50% in many cases) of individuals over the age of 65 had multimorbidity. Where prevalence estimates by gender were reported, females appeared to have higher multimorbidity prevalence rates than males. This is indicative of an association between sex and multimorbidity (evidence of which was provided in multiple studies^74,86). Although there was no uniformity in disease combinations and cut-off points, it followed that the higher the cut-off point, the lower the prevalence. This finding supported an observation by Harrison et al.,⁹¹ where it was found that from 44% (when multimorbidity was defined as 2+ diseases), the prevalence reduced to 27% (for 3+ diseases), 15% (for 4+ diseases), 7% (for 5+ diseases) and only 3% (for 6+ diseases). The highest prevalence estimates in our sample were reported in studies that used the 2+MM definition. Harrison et al.⁹¹ also ascertained that the combination of diseases may make multimorbidity prevalence differ significantly. In the existing literature, a range of different combinations have been proposed from a list of 16 chronic diseases⁹² to a list of 291 diseases⁹³ and anything in between.⁹⁴ Ferrer et al.⁹² argued that an open list of diagnoses should be used, since it gave the highest prevalence estimate. In our sample, the number of diseases ranged from 4 to 40, but a similar trend (i.e. the higher the disease number, the higher the prevalence) was not found. The prevalence of multimorbidity estimated using a list of 40 diseases was, in fact, lower than the prevalence estimated using a list of six diseases. The concern perhaps should be shifted to the fact that there were no specific criteria for disease inclusion in these studies. They were often determined by the authors’ experience and expertise rather than a standardised list. Most commonly, conditions included were those with the highest prevalence or clinical relevance.¹²

Our quantitative synthesis of the data generated a pooled prevalence estimate of 33.1% (95% CI: 30.0–36.3%), which must be interpreted with some caveats. When both age–sex standardised and non-standardised prevalence estimates were included, stratified analysis suggested that there were differences between HICs and LMICs multimorbidity prevalence. Specifically, multimorbidity prevalence was higher in HICs than LMICs. However, when only non-standardised prevalence estimates were taken into consideration, the prevalence of multimorbidity was shown to be marginally higher in LMICs than in HICs. This reverse trend could be due to the fact that of the 34 standardised prevalence estimates removed, 27 of them were from LMICs. The inclusion of these 27 standardised estimates might have deflated the original pooled prevalence estimated for LMICs. Nonetheless, it was not yet clear whether the geographical variation in multimorbidity prevalence was genuine (i.e. multimorbidity prevalence was higher in HICs than LMICs) or whether it simply reflected the differences in diagnostic and data management systems between HICs and LMICs. Xu et al.⁹⁵ suggested that the difference between HICs and LMICs prevalence estimates might also be due to the comparatively limited knowledge on multimorbidity from LMICs compared with HICs, which, consequently, led to fewer publications on multimorbidity prevalence in LMICs.⁹⁵

The reduction in heterogeneity level as a result of stratified analysis was not considerable (all I ² statistics were greater than 99%). In this review, attempts have been made to ensure consistency of prevalence estimates by including in the meta-analysis only studies that used 2+MM definition, disease count measure and self-reported data in community settings.

Implications of findings

Inconsistencies in the prevalence of multimorbidity may lead to an over-/underestimation of healthcare costs, hospital admissions, resources distribution and general disease burden. This, subsequently, hinders the effects of health interventions. The need for a uniform method to estimate multimorbidity prevalence, therefore, becomes more and more urgent. Future research on multimorbidity is urged to follow a standardised protocol, using a consistent disease classification system, disease cut-off point and measure of multimorbidity. Since the age structures of HICs and LMICs are different, both crude and standardised prevalence should be reported. Results from prevalence studies should also be stratified by gender and age. Age groups, where possible, should be categorised using standardised intervals.

Strengths and limitations

The strengths of this review lie in the fact that our study selection and screening processes were vigorous. Our search strategy and inclusion criteria were comprehensive, which, subsequently led to our review being the largest systematic review on multimorbidity prevalence to date. Results after the initial screening were double-checked by a second reviewer, and the full-text screening that followed was carried out independently. Our data extraction and quality assessment were also cross-checked and very few disagreements arose. The studies included in the analysis were mainly of high quality, all community-based and covered both HICs and LMICs. This enabled the findings to be extrapolated to the global population.

This review, however, was not without limitations. Notwithstanding effort made to ensure eligible studies were included, there were still possibilities that potentially eligible articles (especially those not in English) were missed out. This might contain studies that focused on two or more chronic conditions without using the term multimorbidity in their titles or abstracts. Most of the studies in our sample reported multimorbidity prevalence based on self-reported data (though some also used medical examinations such as blood test). Results of such studies were therefore prone to response bias (due to misunderstanding of survey questions or recall timeframe). The majority of studies in this review were cross-sectional, which only allowed estimation of multimorbidity at a certain point in time. In addition, the measures of multimorbidity used in these studies were mostly disease count, with only one exception of the functional comorbidity index (FCI) in one study.⁵⁶ Disease count and FCI were only 2 of nearly 20 different measures available to date. Fortin et al.⁹⁶ reported a much higher prevalence of multimorbidity when using the Cumulative Illness Rating Scale, compared with the prevalence measured by disease count in other studies.⁹⁶ A simple count of chronic diseases, despite being the most common method to estimate multimorbidity prevalence, may sometimes be considered too crude a measure.⁹⁷ That being said, in a cross-sectional, population-based study conducted in Switzerland by Pache et al.,⁵⁶ the prevalence of multimorbidity measured by disease count was found to be higher than that measured by the FCI.⁵⁶ The lack of consistency in measuring and reporting the prevalence of multimorbidity in the included studies was a factor that needs to be taken into account when interpreting findings from our analyses. However, as discussed above, given that there is no consensus about multimorbidity, heterogeneity across studies is inevitable.

Finally, for our meta-analysis, we used absolute numbers (i.e. the number of people reporting multimorbidity and sample sizes) to generate multimorbidity prevalence estimates. However, this strategy did not take into account the weights that were applied to the prevalence estimates in some studies. Our results, therefore, need to be interpreted with this caveat in mind.

Conclusion

Investigating multimorbidity prevalence is of great importance in the study of ageing. This systematic review of 70 studies reveals that a large proportion of the global population, especially those above the age of 65, are affected by multiple chronic diseases. The prevalence estimates of multimorbidity differ among studies. The need for a consistent operationalisation of multimorbidity is evident. It will enable more accurate estimations of disease burden and, consequently, more effective disease management and resources distribution.

Supplemental material

Supplemental Material, Supplement_materials_revised - Prevalence of multimorbidity in community settings: A systematic review and meta-analysis of observational studies

Supplemental Material, Supplement_materials_revised for Prevalence of multimorbidity in community settings: A systematic review and meta-analysis of observational studies by Hai Nguyen, Gergana Manolova, Christina Daskalopoulou, Silia Vitoratou, Martin Prince and A Matthew Prina in Journal of Comorbidity

Footnotes

Acknowledgements

We would like to thank the authors of studies who were contacted and provided further details for this manuscript. We would also like to thank Christina Blanner for her statistical support with the meta-analysis and Melissa Co for her help with the translation of a Portuguese paper included in this review. We extend our thanks also to ATHLOS (Ageing Trajectories of Health: Longitudinal Opportunities and Synergies) project.

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This systematic review was funded by the European Union ’ s Horizon 2020 Research and Innovation Programme under grant agreement number 635316, as part of the ATHLOS Consortium (Ageing Trajectories of Health: Longitudinal Opportunities and Synergies, http://athlosproject.eu/).

ORCID iD

Hai Nguyen

Supplemental material

Supplemental material for this article is available online.

References

Academy of Medical Sciences. Multimorbidity: a priority for global health research. 2018. https://acmedsci.ac.uk/policy/policy-projects/multimorbidity (accessed 12 May 2018).

Ryan

Wallace

O’Hara

, et al. Multimorbidity and functional decline in community-dwelling adults: a systematic review. Health Qual Life Outcomes 2015; 13: 168.

Nunes

Flores

Mielke

, et al. Multimorbidity and mortality in older adults: a systematic review and meta-analysis. Arch Gerontol Geriatr 2016; 67: 130–138.

Vetrano

Palmer

Marengoni

, et al. Frailty and multimorbidity: a systematic review and meta-analysis. J Gerontol A Biol Sci Med Sci 2019; 74(5): 659–666.

Salisbury

Johnson

Purdy

, et al. Epidemiology and impact of multimorbidity in primary care: a retrospective cohort study. Br J Gen Pract 2011; 61(582): e12–21.

Huntley

Johnson

Purdy

, et al. Measures of multimorbidity and morbidity burden for use in primary care and community settings: a systematic review and guide. Ann Fam Med 2012; 10(2): 134–141.

Zulman

Pal Chee

Wagner

, et al. Multimorbidity and healthcare utilisation among high-cost patients in the US veterans affairs health care system. BMJ Open 2015; 5(4): e007771.

Lee

Hamid

Pati

, et al. Impact of noncommunicable disease multimorbidity on healthcare utilisation and out-of-pocket expenditures in middle-income countries: cross sectional analysis. PLoS One 2015; 10(7): e0127199.

Akker

Buntinx

Knottnerus

. Comorbidity or multimorbidity. What’s in a name: a review of literature. Eur J Gen Pract 1996; 2(2): 65–70.

10.

Violan

Foguet-Boreu

Flores-Mateo

, et al. Prevalence, determinants and patterns of multimorbidity in primary care: a systematic review of observational studies. PLos One 2014; 9(7): e102149.

11.

Fortin

Stewart

Poitras

, et al. A systematic review of prevalence studies on multimorbidity: toward a more uniform methodology. Ann Fam Med 2012; 10(2): 142–151.

12.

Pati

Swain

Hussain

, et al. Prevalence and outcomes of multimorbidity in South Asia: a systematic review. BMJ Open 2015; 5(10): e007235.

13.

Shamseer

Moher

Clarke

, et al. Preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) 2015: elaboration and explanation. BMJ-Brit Med J 2015; 350: g7647.

14.

Modesti

Reboldi

Cappuccio

, et al. Panethnic differences in blood pressure in Europe: a systematic review and meta-analysis. PLoS One 2016; 11: e0147601.

15.

Viswanathan

Ansari

Berkman

, et al. Assessing the risk of bias of individual studies in systematic reviews of health care interventions. Rockville: Aency for Healthcare Research and Quality Methods Guide for Comparative Effectiveness Reviews, 2012.

16.

World Bank. World Bank list of economies. 2017. http://iccmoot.com/wp-content/uploads/2017/07/World-Bank-List-of-Economies.pdf (accessed 30 August 2017).

17.

Nyaga

Arbyn

Aerts

. Metaprop: a Stata command to perform meta-analysis of binomial data. Arch Public Health 2014; 72: 39.

18.

Higgins

JPT

Thompson

. Quantifying heterogeneity in a meta-analysis. Stat Med 2002; 21(11): 1539–1558.

19.

StataCorp. Stata statistical software: release 15. College Station: StataCorp LLC, 2017.

20.

Islam

Valderas

Yen

, et al. Multimorbidity and comorbidity of chronic diseases among the senior Australians: prevalence and patterns. PLoS One 2014; 9(1): e83783.

21.

Lujic

Simpson

Zwar

, et al. Multimorbidity in Australia: comparing estimates derived using administrative data sources and survey data. PLoS One [Electronic Resource] 2017; 12(8): e0183817.

22.

Noguchi

Blyth

Waite

, et al. Prevalence of the geriatric syndromes and frailty in older men living in the community: the concord health and ageing in men project. [Erratum appears in Australas]. J Ageing 2017; 36(1): 80. PMID: 28326691. Australasian Journal on Ageing 2016; 35(4): 255–261.

23.

Ruel

Levesque

Stocks

, et al. Understanding the evolution of multimorbidity: evidences from the North West Adelaide Health Longitudinal Study (NWAHS). PLoS One [Electronic Resource] 2014; 9(5): e96291.

24.

Wang

Palmer

Cocker

, et al. Multimorbidity and health-related quality of life (HRQoL) in a nationally representative population sample: implications of count versus cluster method for defining multimorbidity on HRQoL. Health & Qual Life Outcomes 2017; 15(1): 7.

25.

Agborsangaya

Ngwakongnwi

Lahtinen

, et al. Multimorbidity prevalence in the general population: the role of obesity in chronic disease clustering. BMC Public Health 2013; 13: 1161.

26.

Ramond-Roquin

Haggerty

Lambert

, et al. Different Multimorbidity measures result in varying estimated levels of physical quality of life in individuals with multimorbidity: a cross-sectional study in the general population. BioMed Res Int 2016; 2016: 7845438.

27.

Roberts

Rao

Bennett

, et al. Prevalence and patterns of chronic disease multimorbidity and associated determinants in Canada. Health Promot Chronic Dis Prev Can 2015; 35(6): 87–94.

28.

Sakib

Shooshtari

St John

, et al. The prevalence of multimorbidity and associations with lifestyle factors among middle-aged Canadians: an analysis of Canadian Longitudinal Study on Aging data. BMC Public Health 2019; 19(1): 243.

29.

Afshar

Roderick

Kowal

, et al. Multimorbidity and the inequalities of global ageing: a cross-sectional study of 28 countries using the world health surveys. BMC Public Health 2015; 15: 776.

30.

Garin

Koyanagi

Chatterji

, et al. Global multimorbidity patterns: a cross-sectional, population-based, multi-country study. J Gerontol A-Bio Sci Med Sci 2016; 71(2): 205–214.

31.

Loza

Jover

Rodriguez

, et al. Multimorbidity: prevalence, effect on quality of life and daily functioning, and variation of this effect when one condition is a rheumatic disease. Semin Arthritis Rheum 2009; 38(4): 312–319.

32.

Violan

Foguet-Boreu

Hermosilla-Perez

, et al. Comparison of the information provided by electronic health records data and a population health survey to estimate prevalence of selected health conditions and multimorbidity. BMC Public Health 2013; 13: 251.

33.

Buttery

Busch

, et al. Changes in physical functioning among men and women aged 50-79 years in Germany: an analysis of National Health Interview and Examination Surveys, 1997-1999 and 2008-2011. BMC Geriat 2016; 16: 205.

34.

Fuchs

Busch

Lange

, et al. Prevalence and patterns of morbidity among adults in germany. Results of the German telephone health interview survey German Health Update (GEDA) 2009. Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz 2012; 55(4): 576–586.

35.

Kirchberger

Meisinger

Heier

, et al. Patterns of multimorbidity in the aged population results from the KORA-age study. PLoS One 2012; 7(1): e30556.

36.

Laires

Perelman

. The current and projected burden of multimorbidity: a cross-sectional study in a southern Europe population. Eur J Ageing 2018; 16: 181–192. No Pagination Specified.

37.

Rodrigues

Gregorio

Sousa

, et al. Challenges of ageing in Portugal: data from the EpiDoC cohort. Acta Med Port 2018; 31(2): 80–93.

38.

Quinaz Romana

Kislaya

Salvador

, et al. Multimorbidity in Portugal: results from the first national health examination survey. [Portuguese]. Acta Med Port 2019; 32(1): 30–37.

39.

Dhalwani

O’Donovan

Zaccardi

, et al. Long terms trends of multimorbidity and association with physical activity in older English population. Int J Behav Nutr Phys Act 2016; 13: 8.

40.

Humphreys

Jameson

Cooper

, et al. Early-life predictors of future multi-morbidity: results from the Hertfordshire cohort. Age Ageing 2018; 47(3): 474–478.

41.

Johnston

Black

Mercer

, et al. Impact of educational attainment on the association between social class at birth and multimorbidity in middle age in the Aberdeen children of the 1950s cohort study. BMJ Open 2019; 9(1): e024048. (no pagination).

42.

Cheung

JTK

, et al. Geriatric syndromes, multimorbidity, and disability overlap and increase healthcare use among older Chinese. BMC Geriat 2018; 18(1): 147.

43.

Lai

FTT

Guthrie

Wong

SYS

, et al. Sex-specific intergenerational trends in morbidity burden and multimorbidity status in Hong Kong community: an age-period-cohort analysis of repeated population surveys. BMJ Open 2019; 9(1): e023927. (no pagination).

44.

Wong

SYS

Mercer

Woo

, et al. The influence of multi-morbidity and self-reported socio-economic standing on the prevalence of depression in an elderly Hong Kong population. BMC Public Health 2008; 8: 119.

45.

Wei Yap

Heng

. Sex differences in associations between multimorbidity and physical function domains among community-dwelling adults in Singapore. PLoS One 2018; 13(5): e0197443. (no pagination).

46.

Picco

Achilla

Abdin

, et al. Economic burden of multimorbidity among older adults: impact on healthcare and societal costs. BMC Health Serv Res 2016; 16: 173.

47.

Lang

Alexander

Simon

, et al. The impact of multimorbidity on quality of life among midlife women: findings from a U.S. nationally representative survey. J Women’s Health 2015; 24(5): 374–383.

48.

Loprinzi

. Sedentary behavior and medical multimorbidity. Physiol Behav 2015; 151: 395–397.

49.

Kiliari

Theodosopoulou

Papanastasiou

. Multimorbidity and unmet citizens’ needs and expectations urge for reforms in the health system of Cyprus: a questionnaire survey. JRSM Open 2014; 5(1): 2042533313515860.

50.

Larsen

Pedersen

Friis

, et al. A latent class analysis of multimorbidity and the relationship to socio-demographic factors and health-related quality of life. a National population-based study of 162,283 Danish adults. PLoS One [Electronic Resource] 2017; 12(1): e0169426.

51.

Le Cossec

Perrine

Beltzer

, et al. Pre-frailty, frailty, and multimorbidity: prevalences and associated characteristics from two French national surveys. J Nutr Health Aging 2016; 20(8): 860–869.

52.

Ryan

Murphy

Boland

, et al. What is the impact of physical activity and physical function on the development of multimorbidity in older adults over time? A population-based cohort study. J Gerontol A, Biol Sci Med Sci 2018; 73(11): 1538–1544.

53.

Park

Ock

Lee

, et al. Multimorbidity and health-related quality of life in Koreans aged 50 or older using KNHANES 2013-2014. Health & Qual Life Outcomes 2018; 16(1): 186.

54.

Timmermans

Hoogendijk

Broese van Groenou

, et al. Trends across 20 years in multiple indicators of functioning among older adults in the Netherlands. Eur J Public Health 2019: pii: ckz065.

55.

Marengoni

Angleman

Meinow

, et al. Coexisting chronic conditions in the older population: variation by health indicators. Eur J Intern Med 2016; 31: 29–34.

56.

Pache

Vollenweider

Waeber

, et al. Prevalence of measured and reported multimorbidity in a representative sample of the Swiss population. BMC Public Health 2015; 15: 164.

57.

Chen

Cheng

Zhuang

, et al. Multimorbidity among middle-aged and older persons in urban China: prevalence, characteristics and health service utilization. Geriatr Gerontol Int 2018; 18(10): 1447–1452.

58.

Chao

Chen

, et al. Multimorbidity in the community-dwelling elderly in urban China. Arch Gerontol Geriatr 2017; 68: 62–67.

59.

Cai

Cui

, et al. Association of socioeconomic and lifestyle factors with chronic non-communicable diseases and multimorbidity among the elderly in rural southwest China. J Public Health 2019; 12: 12.

60.

Ruel

Shi

Zhen

, et al. Association between nutrition and the evolution of multimorbidity: the importance of fruits and vegetables and whole grain products. Clin Nutr 2014; 33(3): 513–520.

61.

Ding

Zhang

, et al. The association of multimorbidity and disability in a community-based sample of elderly aged 80 or older in Shanghai, China. BMC Geriat 2016; 16(1): 178.

62.

Wang

Wong

, et al. Epidemiology of multimorbidity in China and implications for the healthcare system: cross-sectional survey among 162,464 community household residents in southern China. BMC Med 2014; 12: 188.

63.

Wang

Yan

Liang

, et al. Prevalence and patterns of chronic disease pairs and multimorbidity among older Chinese adults living in a rural area. PLoS One [Electronic Resource] 2015; 10(9): e0138521.

64.

Wang

D’Arcy

, et al. Prevalence and patterns of multimorbidity in northeastern China: a cross-sectional study. Public Health 2015; 129(11): 1539–1546.

65.

Banjare

Pradhan

. Socio-economic inequalities in the prevalence of multi-morbidity among the rural elderly in Bargarh District of Odisha (India). PLoS One [Electronic Resource] 2014; 9(6): e97832.

66.

Shahul

Nanjesh

Naik

, et al. Morbidity pattern among the elderly population in a rural area of Dakshina Kannada, Karnataka - a cross sectional study. Natl J Community Med 2015; 6(2): 222–225.

67.

Kshipra

Perianaygam

. Urbanization, multi-morbidities and preference for health care facility: an insight from Rajasthan, India. J Urban Regional Anal 2018; 10(2): 143–176.

68.

Kumar

Raithatha

Gupta

, et al. Burden of self-reported Noncommunicable diseases in 26 villages of Anand district of Gujarat, India. Int J Chronic Dis 2015; 2015: 260143.

69.

Lalitha

Vinod

Barun

. Rising challenge of multiple morbidities among the rural poor in India - a case of the Sundarbans in West Bengal. Int J Med Sci Public Health 2016; 5(2): 343–350.

70.

Mini

Thankappan

. Pattern, correlates and implications of non-communicable disease multimorbidity among older adults in selected Indian states: a cross-sectional study. BMJ Open 2017; 7(3): e013529.

71.

Singh

Patel

Biswas

, et al. Multimorbidity in South Asian adults: prevalence, risk factors and mortality. J Public Health (Oxf) 2019; 41(1): 80–89.

72.

Amaral

TLM

Amaral

Lima

, et al. Multimorbidity, depression and quality of life among elderly people assisted in the family health strategy in Senador Guiomard, Acre, Brazil. Cien Saude Colet 2018; 23(9): 3077–3084.

73.

Araujo

MEA

Silva

Galvao

, et al. Prevalence and patterns of multimorbidity in amazon region of Brazil and associated determinants: a cross-sectional study. BMJ Open 2018; 8(11): e023398. (no pagination).

74.

De Carvalho

Roncalli

Cancela

, et al. Prevalence of multimorbidity in the Brazilian adult population according to socioeconomic and demographic characteristics. PLoS One 2017; 12(4): e0174322.

75.

De Souza Santos MacHado

Valadares

ALR

Da Costa-Paiva

, et al. Multimorbidity and associated factors in Brazilian women aged 40 to 65 years: a population-based study. Menopause 2012; 19(5): 569–575.

76.

Machado

SSV

Valadares

Costa-Paiva

, et al. Aging, obesity, and multimorbidity in women 50 years or older: a population-based study. Menopause 2013; 20(8): 818–824.

77.

Nunes

Batista

SRR

Andrade

, et al. Multimorbidity: the Brazilian longitudinal study of aging (ELSI-Brazil). Rev Saude Publica 2018; 52(Suppl 2): 10s.

78.

Nunes

Camargo-Figuera

Guttier

, et al. Multimorbidity in adults from a southern Brazilian city: occurrence and patterns. Int J Public Health 2016; 61(9): 1013–1020.

79.

Nunes

Thume

Facchini

. Multimorbidity in older adults: magnitude and challenges for the Brazilian health system. BMC Public Health 2015; 15: 1172.

80.

Valadares

Lui-Filho

Costa-Paiva

, et al. Middle-aged female sexual dysfunction and multimorbidity: a population-based study. Menopause 2016; 23(3): 304–310.

81.

Alaba

Chola

. The social determinants of multimorbidity in South Africa. Int J Equity Health 2013; 12: 63.

82.

Khanam

Streatfield

Kabir

, et al. Prevalence and patterns of multimorbidity among elderly people in rural Bangladesh: a cross-sectional study. J Health Popul Nutr 2011; 29(4): 406–414.

83.

Hien

Berthe

Drabo

, et al. Prevalence and patterns of multimorbidity among the elderly in Burkina Faso: cross-sectional study. Trop Med Int Health 2014; 19(11): 1328–1333.

84.

Camargo-Casas

Suarez-Monsalve

Zepeda

MUP

, et al. Multimorbidity, depressive symptoms, and self-reported health in older adults: a secondary analysis of the Sabe Bogota Study. Rev Inves Clin 2018; 70(4): 192–197.

85.

El Lawindi

Salem

Razik

MMA

, et al. Socioeconomic predictors of morbidities in a rural setting: a community based study. Int J Epidemiol 2019; 15(1): 1–7.

86.

Alimohammadian

Majidi

Yaseri

, et al. Multimorbidity as an important issue among women: results of a gender difference investigation in a large population-based cross-sectional study in West Asia. BMJ Open 2017; 7(5): e013548.

87.

Jerliu

Toci

Burazeri

, et al. Prevalence and socioeconomic correlates of chronic morbidity among elderly people in Kosovo: a population-based survey. BMC Geriatr 2013; 13: 22.

88.

Jankovic

Mirkovic

Jovic-Vranes

, et al. Association between non-communicable disease multimorbidity and health care utilization in a middle-income country: population-based study. Public Health 2018; 155: 35–42.

89.

Ninh Thi

Ninh Hoang

Khanal

, et al. Multimorbidity and its social determinants among older people in southern provinces, Vietnam. Int J Equity Health 2015; 14: 50.

90.

Marengoni

Angleman

Melis

, et al. Aging with multimorbidity: a systematic review of the literature. Ageing Res Rev 2011; 10(4): 430–439.

91.

Harrison

Britt

Miller

, et al. Examining different measures of multimorbidity, using a large prospective cross-sectional study in Australian general practice. BMJ Open 2014; 4(7): e004694.

92.

Ferrer

Formiga

Sanz

, et al. Multimorbidity as specific disease combinations, an important predictor factor for mortality in octogenarians: the Octabaix study. Clin Interv Aging 2017; 12: 223–231.

93.

Quinones

Markwardt

Botoseneanu

. Multimorbidity combinations and disability in older adults. J Gerontol a-Biol 2016; 71(6): 823–830.

94.

van den Bussche

Koller

Kolonko

, et al. Which chronic diseases and disease combinations are specific to multimorbidity in the elderly? Results of a claims data based cross-sectional study in Germany. BMC Public Health 2011; 11: 101.

95.

Mishra

Jones

. Mapping the global research landscape and knowledge gaps on multimorbidity: a bibliometric study. J Glob Health 2017; 7(1): 010414.

96.

Fortin

Bravo

Hudon

, et al. Prevalence of multimorbidity among adults seen in family practice. Ann Fam Med 2005; 3(3): 223–228.

97.

Pathirana

Jackson

. Socioeconomic status and multimorbidity: a systematic review and meta-analysis. Aust Nz J Public Health 2018; 42(2): 186–194.

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