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Abstract

Background:

In aging populations, more elderly patients are going to the intensive care unit (ICU) and surviving. However, the specific factors influencing the occurrence of post-intensive care syndrome in the elderly remain uncertain.

Objective:

To investigate the association between socioeconomic status (SES) and risk of developing dementia within two years following critical care.

Methods:

This study included participants from the Korean National Health Insurance Service Cohort Database who had not been diagnosed with dementia and had been hospitalized in the ICU from 2003 to 2019. Dementia was determined using specific diagnostic codes (G30, G31) and prescription of certain medications (rivastigmine, galantamine, memantine, or donepezil). SES was categorized into low (medical aid beneficiaries) and non-low (National Health Insurance) groups. Through a 1:3 propensity score matching based on sex, age, Charlson comorbidity index, and primary diagnosis, the study included 16,780 patients. We used Cox proportional hazard models to estimate adjusted hazard ratios (HR) of dementia.

Results:

Patients with low SES were higher risk of developing dementia within 2 years after receiving critical care than those who were in non-low SES (HR: 1.23, 95% CI: 1.04–1.46). Specifically, patients with low SES and those in the high-income group exhibited the highest incidence rates of developing dementia within two years after receiving critical care, with rates of 3.61 (95% CI: 3.13–4.17) for low SES and 2.58 (95% CI: 2.20–3.03) for high income, respectively.

Conclusions:

After discharge from critical care, compared to the non-low SES group, the low SES group was associated with an increased risk of developing dementia.

Keywords

Alzheimer’s disease critical care dementia disparity post intensive care syndrome socioeconomic status

INTRODUCTION

Post-intensive care syndrome (PICS) refers to the phenomenon that intensive care unit (ICU) survivors experience in the worsening of impairments in function, cognition, and mental health after critical illness [1 –3]. Dementia occurs in approximately 4–62% of survivors after ICU discharge [4 –7]. It reduces patient quality of life and results in tremendous societal healthcare costs and caregiving workforce needs [1 , 9]. The number of patients who require critical care is increasing, and >80% of patients who receive ICU care survive [1, 10]. The number of patients who experience PICS such as dementia after discharge from ICU is expected to rise; therefore, we need to consider it as an important public healthissue.

PICS occurs more frequently in patients who are prescribed benzodiazepines, have worrying ICU memories, and have comorbid psychiatric illness [11]. In addition, old age, high disease severity, and delirium are risk factors for PICS [12, 13]. A meta-analysis showed that a prevalence of 25–44% for clinically important PTSD symptoms occurred at 1–6 months and 17–34% at 7–12 months after critical illness [11]. Declines in cognitive and physical function after critical care have been demonstrated as long as 6–8 years after hospital discharge [7 , 15]. Despite the growing attention on determining the risk factors for PICS, few studies have examined equity in patient outcomes after critical care [16, 17].

Socioeconomic status (SES) is a strong influencing factor on individual health care utilization and health outcomes [18, 19]. In ICU survival, low SES has been associated with a 31% greater risk of 1-year mortality, and neighborhood disadvantage has been linked to an increase of 14% in disability burden [18, 19]. However, it is unknown whether patients with low economic status have a higher risk of developing dementia after being in ICU than patients who are not of low economic status.

Moreover, economic status has not been clearly reported as an risk factor of dementia onset, and there have been no consistent results regarding the relationship between economic status and dementia. Previous studies have frequently reported that lower SES is linked to a higher risk of dementia, later at the clinic, and with more advanced dementia [20 –22]. However, other studies have reported that individuals with higher SES tend to receive referrals and diagnoses for medical conditions earlier than those with lower SES. This advantage can result in earlier access to treatment, which may delay symptomatic progression [23, 24].

Using nationally representative data for individuals with details of economic status and medical records, we aimed to evaluate whether socioeconomic status is associated with the risk of onset of dementia within 2 years of ICU hospitalization.

METHODS

This study used medical claims records from the Korean National Health Insurance (NHI) Service National Sample Cohort from 2003–2019. The National Health Insurance data (NHID), which included data on clinically determined International Classification of Disease, 10th revision (ICD-10) codes and socio-economic status, was a nationally representative random sample of approximately one million individuals from the Korean population [25]. All patients in the cohort were followed up unless they were excluded due to death or migration. As the NHID data are publicly available, anonymized, and de-identified, informed consent was waived by the Ethics Committee; the study was approved by the Institutional Review Board of Yonsei University’s Health System for academic research. It was conducted in accordance with the Declaration of Helsinki of 1975, as most recently amended.

Participants and design

We included participants who were admitted to a general or tertiary hospital for at least two or more days between 2003 and 2019. The exclusion criteria were as follows: 1) missing covariate values; 2) participants who had been diagnosed with dementia or had taken medication at least once for dementia before or during hospital admission; and 3) patients who were admitted to the ICU for only one day. This selection was made to minimize potential confounding factors on the outcome.

In South Korea, the National Health Insurance (NHI) program is a mandatory and comprehensive social insurance initiative that provides healthcare coverage to all citizens [26]. The government additionally administers a free medical assistance program, which offers healthcare benefits to economically disadvantaged families, including those who qualify through the National Basic Livelihood Security System [27]. Medical Assistance (MA) serves as an alternative for Koreans who cannot afford NHI premiums and closely resembles the Medicaid program in the United States. MA beneficiaries are not required to pay premiums and can access medical facilities either for free or at reduced medical expenses. Therefore, as in previous studies, we intend to use MA beneficiaries as proxy indicators for low SES groups [28, 29].

Low SES group comprised medical aid beneficiaries and non-low SES group was consisted of individuals in NHI. Because NHI premiums are determined based on income and property levels, our data provide that individuals of NHI premiums in the decile which can be used as a indirect indicator for income level for individuals of NHI. We investigate a subgroup analysis to assess the association between not only the type of insurance, but also the income level and the risk of dementia after critical care within 2-year. For this analysis, we divided the non-low SES group into four groups. The 1st to 2nd deciles were classified into the low-income group, the 3rd to 5th deciles were classified into the mid-low-income group, the 6th to 8th deciles were classified into the mid-high-income group, and the 9th to 10th deciles were classified into the high-income group.

The low SES group were then matched with the non-low SES group participants who were non-low SES group using propensity score matching. Propensity scores were calculated using sex, age, Charlson Comorbidity Index (CCI), primary discharge diagnosis from ICU admission and total days in the ICU. After measuring the propensity scores, 1:3 matching was performed using the OneToManyMTCH macro in SAS [30].

Outcome and variables

We defined dementia as an outcome variable in two ways. The first and second diagnoses were included in ICD-10 codes (G30 and G31). Second, in our data, all “F”-related ICD-10 codes are de-identified as vulnerable diseases, so only “F” can be identified. Therefore, we used a prescription of 1 or more medications for dementia (rivastigmine, galantamine, memantine, or donepezil) and the ICD-10 codes for (“F”) were defined as dementia [31, 32]. And to identify the risk of severe dementia, we evaluate a subgroup analysis of people who were prescribed memantine which used to treat dementia that was moderate to severe at the time of the first diagnosis [33, 34].

Independent variables included sociodemographic factors, socioeconomic status, health status, and treatment. Sociodemographic factors consisted of age (<39, 40–49, 50–59, 60–69, ≥70), sex (male or female), and region (metropolitan, city, or rural). Health status consisted of CCI (0–1, 2–3, 4–5 or ≥6). Medical utilization consisted of total days in the ICU divided into tertiles (2–3 days, 4–6 days, and 7 or more days), receiving at least one of three invasive treatments (mechanical ventilator care, renal replacement therapy, or central venous catheter) in the ICU (Yes or No), readmission to the ICU after hospital discharge (Yes or No), and primary discharge diagnosis from hospital (neurologic, oncologic, cardiovascular, respiratory, metabolic, etc.). And the types of hospitals providing ICU services were divided into three categories: tertiary hospitals, which offer advanced and specialized medical care; general hospitals, which have over 100 beds; and hospitals with more than 30 beds.

Statistical analysis

Chi-squared tests were used to determine significant differences in variables between participants who had dementia and those who did not. Statistical significance was set at p < 0.05. The propensity score was derived using logistic regression to calculate the probability of socioeconomic status according to sex, age, CCI, and primary discharge diagnosis. We calculated the incidence rate (IR) and incidence rate ratio (IRR) of dementia and the 95% CI with a generalized estimating equation using a Poisson distribution and expressed it as the incidence of dementia per 100,000 person-days. A Cox proportional hazards model was used to evaluate the association between socioeconomic status and incidence of dementia among participants who received critical care. For each participant, the index date was defined as the date of discharge from hospital, and the date of diagnosis of dementia or the date of prescription was defined as the final event date. We censored participants who died during follow-up or did not develop dementia. The results were reported as hazard ratios (HRs) and 95% confidence intervals (CIs) for the risk of dementia. Data were analyzed using SAS 9.4 (SAS Institute Inc., Cary, NC, USA).

RESULTS

After applying the exclusion criteria, a total of 46,503 individuals remained. Subsequently, a 1:3 matching process was conducted, resulting in the selection of 4,195 individuals classified as the low SES group and 12,585 individuals classified as the non-low SES group (Fig. 1).

Fig. 1

Flow chart of population selection.

Table 1 presents the general characteristics of the participants. Of the 16,780 participants included in our study, 621 (3.7%) developed dementia after being discharged from hospital. Among patients in low SES, 188 (4.5%) developed dementia. In addition, 433 (3.4%) patients who were in the non-low SES group developed dementia. There was a statistically significant difference in dementia development between the low SES and non-SES groups.

Table 1

General characteristics of the baseline study population

Variables	Total		The low SES		The non-low SES		p
	N	%	N	%	N	%
Total	16,780	100.0	4,195	25.0	12,585	75.0
Gender							0.9715
Male	8,760	52.2	2,189	52.2	6,571	52.2
Female	8,020	47.8	2,006	47.8	6,014	47.8
Age							0.9932
-39	1,076	6.4	269	6.4	807	6.4
40–49	1,669	9.9	417	9.9	1,252	9.9
50–59	2,923	17.4	741	17.7	2,182	17.3
60–69	2,859	17.0	711	16.9	2,148	17.1
70-	8,253	49.2	2,057	49.0	6,196	49.2
Region							0.0001
Metropolitan	2,983	17.8	600	14.3	2,383	18.9
City	7,148	42.6	1,724	41.1	5,424	43.1
Rural	6,649	39.6	1,871	44.6	4,778	38.0
Length of ICU stay							0.8648
2∼3 days	6,653	39.6	1,650	39.3	5,003	39.8
4∼6 days	4,103	24.5	1,026	24.5	3,077	24.4
7 and more days	6,024	35.9	1,519	36.2	4,505	35.8
Invasive treatment							0.0383
Yes	7,872	46.9	1,910	45.5	5,962	47.4
No	8,908	53.1	2,285	54.5	6,623	52.6
Charlson Comorbidity Index						0.954
0∼1	1,762	10.5	447	10.7	1,315	10.4
2∼3	3,311	19.7	833	19.9	2,478	19.7
4∼5	4,619	27.5	1,143	27.2	3,476	27.6
6∼	7,088	42.2	1,772	42.2	5,316	42.2
ICU readmission							0.0001
Yes	12,935	77.1	3,066	73.1	9,869	78.4
No	3,845	22.9	1,129	26.9	2,716	21.6
Primary discharge diagnosis from ICU admission							0.9934
Oncologic	1,565	9.3	391	9.3	1,174	9.3
Neurologic	588	3.5	141	3.4	447	3.6
Cardiovascular	4,796	28.6	1,199	28.6	3,597	28.6
Respiratory	2,230	13.3	565	13.5	1,665	13.2
Metabolic	478	2.8	119	2.8	359	2.9
Else	7,123	42.4	1,780	42.4	5,343	42.5
Type of hospital							0.0001
Tertiary hospital	5,642	33.6	1,035	24.7	4,607	36.6
General hospital	10,326	61.5	2,852	68.0	7,474	59.4
Hospital	812	4.8	308	7.3	504	4.0

Table 2 presents the findings of the IRR and Cox proportional hazard regression analysis for the association between socioeconomic status and the incidence of dementia within 2 years after ICU discharge. 188 of the patients with low SES developed dementia over 5,197,140 person-days (IR: 3.6 cases per 100,000 person-days). Patients with low SES were at higher risk of developing dementia within 2 years after receiving critical care than those who were in non-low SES group (HR: 1.23, 95% CI: 1.04–1.46). A longer stay in ICU was also a statistically significant factor affecting the risk of developing dementia; patients who stayed in ICU for >6 days were at higher risk than patients who were in ICU for 2–3 days (HR 1.43, CI 1.19–1.73). Also, patients with low SES did not exhibit a significantly higher risk of developing moderate to severe dementia within two years after receiving critical care, compared to those in the non-low SES group (HR: 1.01, 95% CI: 0.47–2.14, Supplementary Table 1).

Table 2

Association between the socioeconomic status and the risk of dementia after critical care within 2 years

Variables	Total person-days	Incidence Rate per 100,000 person-days	Risk of dementia
			IRR	95% CI	HR	95% CI
Socioeconomic status
The low SES	5,197,140	3.6	1.65	(1.39–1.97)	1.23	(1.04–1.46)
The non-low SES	22,233,767	1.9	1.00		1.00
Gender
Male	15,147,280	1.6	1.00		1.00
Female	12,283,627	3.1	1.09	(0.92–1.29)	1.10	(0.93–1.29)
Age
-39	3,008,191	0.1	1.00		1.00
40–49	4,363,308	0.6	4.17	(1.44–12.09)	4.35	(1.52–12.51)
50–59	6,292,161	0.7	5.36	(1.91–15.06)	4.24	(1.51–11.90)
60–69	5,138,113	1.8	13.81	(5.02–38.04)	8.04	(2.91–22.18)
70-	8,629,134	5.3	38.57	(14.23–104.58)	20.29	(7.48–55.04)
Region
Metropolitan	5,042,445	2.2	1.00		1.00
City	12,000,222	1.9	0.84	(0.67–1.06)	0.90	(0.72–1.12)
Rural	10,388,240	2.7	0.96	(0.77–1.20)	0.99	(0.80–1.24)
Length of icu stay
2∼3 days	14,383,834	2.0	1.00		1.00
4∼6 days	6,782,699	2.2	1.13	(0.92–1.37)	1.13	(0.93–1.37)
7 and more days	6,264,374	3.0	1.74	(1.43–2.11)	1.43	(1.19–1.73)
Invasive treatment
Yes	11,227,292	1.8	0.76	(0.64–0.92)	1.74	(0.62–0.88)
No	16,203,615	2.6	1.00		1.00
Charlson Comorbidity Index
0∼1	2,615,840	1.1	1.00		1.00
2∼3	4,914,909	1.9	0.99	(0.65–0.66)	1.03	(0.68–1.55)
4∼5	7,433,025	2.5	1.28	(0.86–1.90)	1.40	(0.95–2.05)
6∼	12,467,133	2.5	1.30	(0.88 1.92)	1.46	(1.00 2.13)
ICU readmission
Yes	7,210,410	2.5	0.94	(0.79–1.12)	1.06	(0.90–1.26)
No	20,220,497	2.2	1.00		1.00
Primary discharge diagnosis from ICU admission
Oncologic	1,840,184	1.3	1.00		1.00
Neurologic	1,177,046	2.2	2.20	(1.25–3.88)	3.51	(1.89–6.52)
Cardiovascular	8,553,989	2.5	1.27	(0.82–1.96)	2.49	(1.49–4.16)
Respiratory	2,255,904	3.2	1.72	(1.07–2.76)	2.26	(1.30–3.91)
Metabolic	734,069	3.4	2.26	(1.28–4.01)	3.54	(1.87–6.68)
Else	12,869,715	2.0	1.49	(0.97–2.30)	2.57	(1.54–4.29)
Type of hospital
Tertiary hospital	10,268,385	1.6	1.00		1.00
General hospital	15,873,543	2.7	1.22	(1.00–1.47)	1.13	(0.94–1.35)
Hospital	1,288,979	2.9	1.04	(0.72–1.52)	0.94	(0.64–1.38)

Kaplan–Meier survival curves showed that the risk of developing dementia among patients with low SES was higher than that in the non-low SES group (log-rank test, p < 0.001; Fig. 2).

Fig. 2

Kaplan-Meier survival curves for developing dementia after critical care within 2-year according to socioeconomic status of patients.

Figure 3 shows the incidence rate of dementia patients per 100,000 by subgroup to patients who were in low SES had the highest incidence rate of developing dementia (IR: 3.61, 95% CI: 3.13–4.17) and the high-income group also had high incidence rate of developing dementia (IR: 2.58, 95% CI: 2.20–3.03).

Fig. 3

Incidence rate of dementia patients per 100,000 population stratified by income level.

Table 3 shows the results of the subgroup analysis assessing the impact of developing dementia within different periods after hospital discharge. Patients with low SES had a marginally significant higher risk of developing dementia within 18 months after being discharged from hospital (within 18 months, HR: 1.17, 95% CI: 0.97–1.41).

Table 3

Association between the socioeconomic status and the risk of dementia by various periods

Variables	Risk of Dementia
	Within 3 months		Within 6 months		Within 12 months		Within 18 months
	HR	95% CI	HR	95% CI	HR	95% CI	HR	95% CI
Socioeconomic status
The low SES	1.02	(0.74–1.42)	1.02	(0.78–1.33)	1.11	(0.90–1.37)	1.17	(0.97–1.41)
The non-low SES	1.00		1.00		1.00		1.00

DISCUSSION

Our study investigated the effect of socioeconomic status on dementia development within 2 years after critical care, using national health insurance cohort data. Our results showed that the risk of developing dementia after critical care was higher for patient with low SES than for those who were not. Our finding that economic vulnerability might lead to impairment of cognitive function and dementia after ICU survival has meaningful implications for patients, families, and healthcare systems.

Lower SES is linked to higher ICU, in-hospital, 30-day, and long-term mortality [35, 36]. In addition, older adults receiving Medicaid and Medicare have a strong association with probable dementia in the United States [16]. Neighborhood socioeconomic disadvantage has a 9% higher risk of a higher disability burden after a critical illness following discharge from critical care compared with those in more advantaged areas [19]. Low SES reflects deprivation, which indicates a lack of resources or opportunities for healthcare utilization and poor access to health care. Additionally, those with low SES are more frequently exposed to adverse environments and have less knowledge of their health conditions. Our results suggest that a low SES may significantly contribute to the differential development of cognitive sequelae among survivors receiving critical care.

Our results showed an association between various income levels and risk of dementia development within 2 years of critical care. The association had an U-shape In a previous study, the rich tended to receive referrals and diagnoses for their medical conditions at an earlier stage than those with lower SES. As a result, the rich had the advantage of accessing earlier treatment, which potentially slowed down symptomatic progression [23]. In Korean national reports, both inpatient and outpatient centers were less medically utilized by patient with low SES s with dementia than rich patients with dementia [37].

For oncological and pulmonary diseases, ICU admission may have contributed to the observed socioeconomic differences in cognitive decline. These diseases are characterized by chronic conditions for which disease outcomes may be influenced by accessibility of healthcare and continuity of care, which are known to be worse for those with low SES [16 , 39]. These results suggest that patients with certain diseases, especially those with low SES, should receive additional care or follow-up related to cognitive function and dementia after receiving critical care.

Many studies related to ICU syndrome have examined various sequelae, such as disability, weakness, physical impairment, and cognitive and psychosocial impairment. Discussions on when each sequela occurs after ICU discharge and for how long they persist are ongoing but there are no consistent results [1 , 40–42]. Our results showed that the decline in cognitive function within one year of discharge from the ICU varies significantly according to SES status, and there is no difference in income status before six months. If patients receive long-term ICU treatment or have more comorbidities, the risk of dementia increases. In our study, our primary finding indicated the dementia risk associated with socioeconomic status during the post-ICU period. However, it is important to recognize that individuals with lower socioeconomic status can affect cognitive function irrespective of ICU admission. Establishing a definitive link between ICU admission and the onset of dementia is a complex issue. Nevertheless, in our research, we made efforts to address this concern by excluding individuals who had previously received dementia medication or a dementia diagnosis before their ICU admission.

This study has several limitations. First, we only considered dementia diagnosis in terms of ICD codes and drug prescriptions. Due to data limitations, we were unable to identify cases of mild and moderate cognitive impairment. However, a subgroup analysis was conducted to assess the impact of SES on the risk of severe dementia by using patients who were prescribed memantine, a medication typically used to treat moderate to severe dementia. Also, we excluded all patients with dementia at baseline. Second, since there was a data limitation regarding blinding-sensitive diseases such as delirium, we could not determine whether the patient experienced delirium during hospitalization. Further research is needed, because this may have affected our dependent variables. Third, the use of income status as a proxy for socioeconomic disadvantage in studies on health outcomes, including disability, is widespread. However, this approach does not distinguish between specific social and economic risk factors.

Conclusions

In summary, this study examined the association between socioeconomic status and the risk of developing dementia within 2 years of critical care. Our results showed that patients in socioeconomic status had a higher risk of developing dementia after critical care than those who were not. Our finding that economic vulnerability might lead to impairment of cognitive function and dementia after ICU survival has meaningful implications for patients, families, and healthcare systems.

Footnotes

ACKNOWLEDGMENTS

We would like to thank the colleagues from the Department of Public Health, Graduate School of Yonsei University for advice on this manuscript.

FUNDING

This work was supported by the Technology innovation program (20024263, Development and validation of a digital phenotype based platform for the treatment and prevention of MCI using a multidisciplinary approach to decrease dementia risk) funded by the funded by the Ministry of Trade, Industry and Energy (MOTIE, Korea).

CONFLICT OF INTEREST

The authors have no conflict of interest to report.

DATA AVAILABILITY

The data that support the findings of this study are available from the National Health Insurance Sharing Service but restrictions apply to the availability of these data.

The supplementary material is available in the electronic version of this article: .

References

Needham

, Davidson

, Cohen

, Hopkins

, Weinert

, Wunsch

, Zawistowski

, Bemis-Dougherty

, Berney

, Bienvenu

(2012) Improving long-term outcomes after discharge from intensive care unit: Report from a stakeholders’ conference. Crit Care Med 40, 502–509.

Pandharipande

, Girard

, Jackson

, Morandi

, Thompson

, Pun

, Brummel

, Hughes

, Vasilevskis

, Shintani

(2013) Long-term cognitive impairment after critical illness. N Engl J Med 369, 1306–1316.

Marra

, Pandharipande

, Girard

, Patel

, Hughes

, Jackson

, Thompson

, Chandrasekhar

, Ely

, Brummel

(2018) Co-occurrence of post-intensive care syndrome problems among 406 survivors of critical illness. Crit Care Med 46, 1393.

Wilcox

, Brummel

, Archer

, Ely

, Jackson

, Hopkins

(2013) Cognitive dysfunction in ICU patients: Risk factors, predictors, and rehabilitation interventions. Crit Care Med 41, S81–S98.

Timmers

, Verhofstad

, Moons

, van Beeck

, Leenen

(2011) Long-term quality of life after surgical intensive care admission. Arch Surg 146, 412–418.

Jackson

, Hart

, Gordon

, Shintani

, Truman

, May

, Ely

(2003) Six-month neuropsychological outcome of medical intensive care unit patients. Crit Care Med 31, 1226–1234.

Iwashyna

, Ely

, Smith

, Langa

(2010) Long-term cognitive impairment and functional disability among survivors of severe sepsis. JAMA 304, 1787–1794.

Hashem

, Nallagangula

, Nalamalapu

, Nunna

, Nausran

, Robinson

, Dinglas

, Needham

, Eakin

(2016) Patient outcomes after critical illness: A systematic review of qualitative studies following hospital discharge. Crit Care 20, 345.

Wolters

, Slooter

, van der Kooi

, van Dijk

(2013) Cognitive impairment after intensive care unit admission: A systematic review. Intensive Care Med 39, 376–386.

10.

Jackson

, Pandharipande

, Girard

, Brummel

, Thompson

, Hughes

, Pun

, Vasilevskis

, Morandi

, Shintani

(2014) Depression, post-traumatic stress disorder, and functional disability in survivors of critical illness in the BRAIN-ICU study: A longitudinal cohort study. Lancet Respir Med 2, 369–379.

11.

Parker

, Sricharoenchai

, Raparla

, Schneck

, Bienvenu

, Needham

(2015) Posttraumatic stress disorder in critical illness survivors: A metaanalysis. Crit Care Med 43, 1121–1129.

12.

Lee

, Kang

, Jeong

(2020) Risk factors for post–intensive care syndrome: A systematic review and meta-analysis. Aust Crit Care 33, 287–294.

13.

, Kang

, Park

, Cho

, Suh

, Chung

(2022) Association between the presence of delirium during intensive care unit admission and cognitive impairment or psychiatric problems: The Korean ICU National Data Study. J Crit Care 10, 7.

14.

Rothenhäusler

, Ehrentraut

, Stoll

, Schelling

, Kapfhammer

H-P

(2001) The relationship between cognitive performance and employment and health status in long-term survivors of the acute respiratory distress syndrome: Results of an exploratory study. Gen Hosp Psychiatry 23, 90–96.

15.

Hopkins

, Jackson

(2006) Long-term neurocognitive function after critical illness. Chest 130, 869–878.

16.

Jain

, Murphy

, O’Leary

, Leo-Summers

, Ferrante

(2022) Association between socioeconomic disadvantage and decline in function, cognition, and mental health after critical illness among older adults: A cohort study. Ann Intern Med 175, 644–655.

17.

Haddad

, Mart

, Wang

, Lindsell

, Raman

, Nordness

, Sharp

, Pandharipande

, Girard

, Ely

(2020) Socioeconomic factors and intensive care unit-related cognitive impairment. Ann Surg 272, 596.

18.

Cha

, Oh

, Song

I-A

(2019) Impacts of financial coverage on long-term outcome of intensive care unit survivors in South Korea. Yonsei Med J 60, 976–983.

19.

Falvey

, Murphy

, Leo-Summers

, Gill

, Ferrante

(2021) Neighborhood socioeconomic disadvantage and disability after critical illness. Criti Care Med 50, 733–741.

20.

Jung

, Choi

, Park

, Jang

, Park

(2020) Association between pulse pressure and onset of dementia in an elderly Korean population: A cohort study. Int J Environ Res Public Health 17, 1657.

21.

Moon

, Seo

, Lee

, Kim

, Park

(2019) Associations among health insurance type, cardiovascular risk factors, and the risk of dementia: A prospective cohort study in Korea. Int J Environ Res Public Health 16, 2616.

22.

Fischer

, Yeung

, Hansen

, Gibbons

, Fornazzari

, Ringer

, Schweizer

(2009) Impact of socioeconomic status on the prevalence of dementia in an inner city memory disorders clinic. Int Psychogeriatr 21, 1096–1104.

23.

Petersen

, Wehberg

, Packness

, Svensson

, Hyldig

, Raunsgaard

, Andersen

, Ryg

, Mercer

, Søndergaard

, Waldorff

(2021) Association of socioeconomic status with dementia diagnosis among older adults in Denmark. JAMA Network Open 4, e2110432e2110432.

24.

Qian

, Schweizer

, Fischer

(2014) Impact of socioeconomic status on initial clinical presentation to a memory disorders clinic. Int Psychogeriatr 26, 597–603.

25.

Lee

, Lee

, Park

, Shin

, Kim

(2017) Cohort profile: The national health insurance service–national sample cohort (NHIS-NSC), South Korea. Int J Epidemiol 46, e15e15.

26.

Kim

, Lee

(2010) Developments and general features of national health insurance in Korea. Soc Work Public Health 25, 142–157.

27.

Lee

, Kim

(2012) Social Security: Principles and Practices. Hakjisa, Seoul

28.

Kim

, Lee

, Lim

, Seo

, Kim

, Zo

, Kim

(2020) Relationship of socioeconomic status to arterial stiffness: Comparison between medical aid beneficiaries and national health insurance beneficiaries. Am J Hypertens 33, 718–725.

29.

Kim

, Lee

, Bae

, Kim

, Lim

, Yoon

, Lee

, Jo

M-W

(2018) Socioeconomic status can affect pregnancy outcomes and complications, even with a universal healthcare system. Int J Equity Health 17, 2.

30.

Parsons

(2004) Performing a 1: N Case-Control Match on Propensity Score. Proceedings of the Twenty-Ninth Annual SAS Users Group International Conference. SAS Institute Inc

31.

Kim

, Yang

, Sung

, Jang

, Yu

, Kim

, Uhm

, Kim

, Pak

, Lee

(2020) Less dementia after catheter ablation for atrial fibrillation: A nationwide cohort study. Eur Heart J 41, 4483–4493.

32.

Lee

, Han

, Cho

, Park

, Kwon

, Kang

, Yoon

, Kim

(2018) Variability in metabolic parameters and risk of dementia: A nationwide population-based study. Alzheimers Res Therapy 10, 110.

33.

Reisberg

, Doody

, Stöffler

, Schmitt

, Ferris

, Möbius

(2003) Memantine in moderate-to-severe Alzheimer’s disease. N Engl J Med 348, 1333–1341.

34.

Winblad

, Poritis

(1999) Memantine in severe dementia: Results of the 9M-best study (benefit and efficacy in severly demented patients during treatment with memantine). Int J Geriatr Psychiatry 14, 135–146.

35.

, Dobb

, Knuiman

, Finn

, Webb

(2008) The effect of socioeconomic status on outcomes for seriously ill patients: A linked data cohort study. Med J Aust 189, 26–30.

36.

Jones

JRA

, Berney

, Connolly

, Waterland

, Denehy

, Griffith

, Puthucheary

(2019) Socioeconomic position and health outcomes following critical illness: A systematic review. Crit Care Med 47, e512–e521.

37.

Lee

, Han

, Ann

, Park

, Jin

(2018) Analysis of health care utilization of patients with dementia. Health Insurance Review & Assessment Service, Wonju.

38.

Bahiru

, Ziaeian

, Moucheraud

, Agarwal

, Xu

, Matsouaka

, DeVore

, Heidenreich

, Allen

, Yancy

(2021) Association of dual eligibility for Medicare and Medicaid with heart failure quality and outcomes among Get With The Guidelines–Heart Failure hospitals. JAMA Cardiol 6, 791–800.

39.

Spitzer

, Stefan

, Priya

, Pack

, Pekow

, Lagu

, Pinto-Plata

, ZuWallack

, Lindenauer

(2019) Participation in pulmonary rehabilitation after hospitalization for chronic obstructive pulmonary disease among Medicare beneficiaries. Ann Am Thorac Soc 16, 99–106.

40.

Harvey

(2012) The truth about consequences—Post-intensive care syndrome in intensive care unit survivors and their families. Crit Care Med 40, 2506–2507.

41.

Desai

, Law

, Needham

(2011) Long-term complications of critical care. Crit Care Med 39, 371–379.

42.

Davidson

, Jones

, Bienvenu

(2012) Family response to critical illness: Postintensive care syndrome–family. Crit Care Med 40, 618–624.

Socioeconomic Status and Dementia Risk Among Intensive Care Unit Survivors: Using National Health Insurance Cohort in Korea

Abstract

Background:

Objective:

Methods:

Results:

Conclusions:

Keywords

INTRODUCTION

METHODS

Participants and design

Outcome and variables

Statistical analysis

RESULTS

DISCUSSION

Conclusions

Footnotes

ACKNOWLEDGMENTS

FUNDING

CONFLICT OF INTEREST

DATA AVAILABILITY

References