Abstract
To estimate the prevalence of screen-detected mild cognitive impairment (MCI) and identify associated sociodemographic, lifestyle, and functional factors among older adults attending outpatient care in a low- and middle-income country. A cross-sectional study was conducted between May 2024 and February 2025 among adults aged ≥60 years attending an outpatient department in southern Vietnam. Data were collected through interviews and standardized assessments, including the Mini-Mental State Examination and the Lawton Instrumental Activities of Daily Living scale. Associations were examined using logistic regression. Of 631 participants, 30.1% screened positive for MCI. Older age, unmarried status, unstable income, lower education, reduced recreational activity, and lower IADL scores were associated with higher odds of MCI, with age and recreational inactivity showing the strongest effects. The high prevalence of MCI among older outpatients highlights the need to integrate cognitive and social-functional screening into outpatient care in resource-limited settings. Enhancing recreational and social engagement may mitigate early cognitive decline.
Introduction
Population aging is accelerating across low- and middle-income countries (LMICs), with Southeast Asia projected to experience one of the most rapid demographic shifts globally. 1 In Vietnam, the proportion of individuals aged 65 and above is expected to double from 7% in 2020 to 14% by 2035, a rate faster than in many developed countries. 2 By 2024, adults aged 60 and above already accounted for over 14% of the population. 3 This aging shift brings growing health challenges, notably cognitive decline. Modeling studies predict a sharp rise in cognitive impairment across Southeast Asia, including Vietnam. 4
Mild cognitive impairment (MCI) is a transitional state between normal aging and dementia. 5 Although basic daily functioning is preserved, MCI affects higher-order cognitive and social abilities. 6 Its burden extends to economic and survival consequences, with annual care costs exceeding 24 000 USD in the United States and high 5-year mortality reported among older adults with dementia in LMICs.7,8
In Vietnam, many older adults bypass lower-level facilities and seek care at secondary-level hospitals. 9 Cognitive complaints are increasingly noted in outpatient populations, yet most existing studies have relied on community-based samples, potentially underestimating the burden in clinical settings.10 -13 Information routinely collected at triage, including social and functional data, may provide a practical opportunity for early recognition. 14
Given the rapid aging of the population, understanding how common MCI is among older outpatients and the factors associated with it can support better planning of services for older adults. This study aimed to estimate the prevalence of screen-detected MCI and examine its sociodemographic, lifestyle, and functional correlates among older outpatients in a secondary-level hospital in Vietnam.
Materials and Methods
Study Design and Participants
A cross-sectional study was conducted among older adults attending the outpatient department of Nhan Dan Gia Dinh Hospital, a secondary-level public hospital in southern Vietnam between May 2024 and February 2025. We followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline (Supplemental Material). 15
Eligible participants were adults aged 60 years or older, literate in Vietnamese, and able to complete the full cognitive screening protocol. Exclusion criteria included uncorrected sensory impairments, acute medical conditions affecting attention, psychiatric disorders unrelated to dementia, significant depressive symptoms (GDS-15 ≥5), current use of medications with potential cognitive side effects, and recent participation in structured cognitive training programs.
Screening began with a brief conversation to confirm willingness to participate and language fluency before applying formal eligibility criteria. Individuals who sought only to check their MMSE score, declined written consent, or withdrew after partial participation were excluded.
Data Collection and Tools
Before recruitment, the research team coordinated with outpatient administrative staff to identify optimal time periods when older adults most frequently attended consultations. This minimized disruption to clinical operations and facilitated natural engagement with potential participants in waiting areas.
To reduce reluctance in discussing memory concerns, interviews began with general health topics before cognitive questions. All assessments were conducted by trained researchers. Medication use and chronic conditions were verified through medical-record review and consultation with treating physicians. Demographic data including age, gender, marital status, education, and financial security were obtained through structured face-to-face interviews.
Recreational Activities
Social recreational engagement was assessed using interviewer-administered questions focusing on recent participation in activities involving interpersonal interaction. Interviews followed a standardized script with predefined probes to clarify uncertain responses. Participants reporting such engagement were asked about frequency, and their participation was categorized as regular when occurring at least 3 times/week, each lasting ≥30 minutes and sustained for at least 1 month. Less frequent participation was considered irregular, while those reporting none were classified as having no engagement.
Hypertension and Diabetes Status
Hypertension and diabetes mellitus were each categorized as no documented diagnosis, controlled, or uncontrolled, based on medical record review and participant self-report. No documented diagnosis indicated absence of both patient-reported history and chart documentation. Controlled referred to a documented condition with stable treatment, no recent medication change or hospitalization (within 3 months), and recent clinical values within target ranges (BP <140/90 mmHg; HbA1c <7.5%).
Physical Activity-Limiting Conditions
Defined as any acute or chronic condition that significantly restricted mobility or posed exertional risk. Verification included both self-report and review of medical instructions, supplemented by contextual questions (“Has any doctor told you to avoid certain exercises?”).
Functional Status
Functional autonomy was evaluated using the culturally adapted Vietnamese version of the Lawton Instrumental Activities of Daily Living (IADL) scale. 16 The scale evaluates 8 domains, including use of the telephone, shopping, food preparation, housekeeping, laundry, transportation, medication management, and financial handling. Each domain is scored to reflect the highest level of independent functioning, and total scores range from 0 (complete dependence) to 8 (full independence), with higher scores indicating greater autonomy. The Lawton IADL has demonstrated strong psychometric performance, with excellent reliability (inter-rater ICC ~0.57-0.99 and test-retest ICC around 0.90-0.99), good construct validity, and moderate criterion validity. 17
Criteria for MCI Classification
MCI in this study was identified based on (i) self-reported memory complaints, (ii) Mini-Mental State Examination (MMSE) scores of 24 to 29, (iii) relatively preserved instrumental functioning on the Lawton IADL scale (score ≥5), 18 and (iv) absence of a clinical diagnosis of dementia.5,19 As this study used screening instruments rather than comprehensive clinical and neuropsychological assessments, the identified cases should be interpreted as screen-detected MCI risk rather than clinically confirmed MCI. Therefore, throughout this manuscript, the term “MCI” refers to screen-detected MCI identified using the above criteria.
The MMSE is a 30-point cognitive screening tool comprising items across multiple cognitive domains. 20 Previous studies have reported moderate-to-high reliability for the MMSE, with test-retest coefficients typically ranging from ~0.80 to 0.95, and overall satisfactory construct and criterion validity as a cognitive screening instrument. 21 Total scores range from 0 to 30, with higher scores indicating better global cognitive performance. The Vietnamese version of the MMSE, officially endorsed by the Ministry of Health, was used to ensure linguistic and cultural validity. 22
The MMSE range of 24 to 29 was selected based on field considerations and published evidence indicating that scores below 24 often reflect dementia, whereas higher values may still capture subtle impairments.23 -25 This range was appropriate for outpatient screening contexts in low-resource settings.
Because MMSE performance is known to be influenced by educational attainment, 26 education-adjusted thresholds were considered during study design. However, standardized education-specific MMSE cut-offs validated for this clinical context are currently limited. Therefore, the MMSE and the selected cut-off range were used to identify screen-detected cognitive risk consistent with possible MCI, rather than to establish a definitive clinical diagnosis. Prevalence estimates should therefore be interpreted as representing the proportion of participants who screened positive for potential cognitive impairment.
To confirm the absence of diagnosed dementia, medical records were reviewed. Participants with borderline MMSE scores, inconsistent interview responses, or caregiver-reported cognitive concerns were referred for further evaluation by an independent neurologist or geriatrician.
Pilot Study
A preliminary pilot study tested the feasibility and reliability of the screening protocol and instruments (MMSE, GDS-15, Lawton IADL) before full-scale implementation. 27 The pilot achieved an 89.4% enrollment rate, 98% screening completion, and full adherence among eligible participants. Internal consistency was acceptable for the instruments used in the main study (MMSE α = .72; GDS-15 α = .71; Lawton IADL α = .73)
Ethics
The study was approved by the Biomedical Research Ethics Committee of the University of Medicine and Pharmacy at Ho Chi Minh City (reference number: 625/HĐĐĐ-ĐHYD, dated May 5, 2024) and by the Ethics Committee of Nhan Dan Gia Dinh Hospital (reference number: 65/NDGĐ-HĐĐĐ, dated May 17, 2024). The study adhered to the ethical principles outlined in the revised 1987 Declaration of Helsinki, and written informed consent was provided by all participants.
Statistical Methods
All analyses were performed using SPSS version 27. Descriptive statistics summarized sample characteristics. Group comparisons between participants with and without MCI used independent t-tests or Mann-Whitney U tests for continuous variables, and chi-square or Fisher’s exact tests for categorical variables.
Univariate logistic regressions were first performed for all candidate factors. Variables with P < .25 were entered into the multivariable model to avoid excluding potentially relevant factors. 28 For categorical variables with more than 2 levels, overall significance was assessed.
Multicollinearity was assessed using variance inflation factors (VIF), with values >2.5 indicating potential collinearity. 29 Model calibration was evaluated with the Hosmer-Lemeshow goodness-of-fit test to verify alignment between predicted probabilities and observed MCI frequencies across risk deciles. 30 A non-significant result indicated acceptable calibration. All statistical tests were 2-tailed, and significance was defined as P < .05.
Results
Characteristics of the Participants
Of the 726 older adults approached, 653 (89.9%) agreed to screening. Twenty-two individuals were excluded: 7 preferred to complete only the MMSE, 7 declined to complete the MMSE, 3 scored ≥5 on the GDS-15, 3 had uncorrected sensory impairments, and 2 were taking medications with cognitive side effects. The final analytical sample comprised 631 participants (Figure 1).
Flow chart of the study.
Among 631 outpatients aged ≥60 years (mean 65.9 ± 5.3 years; 57.7% women), most were married/cohabiting (56.3%), completed senior high school (75.3%), and reported financial stability (72.1%). Regular social-recreational engagement was uncommon (22.6%), though functional autonomy remained high (mean Lawton IADL 6.8 ± 0.9). Regarding metabolic health, 46.7% had diabetes, of whom 27.0% were uncontrolled; hypertension was present in 63.8%, with 13.4% uncontrolled.
Nearly one-third (30.1%) of older outpatients screened positive for MCI. Compared with participants without MCI, those with MCI were older (70.2 vs 64.1 years, P < .001) and had a higher proportion of individuals who were single, divorced, separated, or widowed (64.7% vs 34.7%, P < .001). Participants with MCI were also less likely to have completed senior high school (56.8% vs 83.2%, P < .001). Participants with MCI reported lower levels of recreational activity (regular participation: 5.3% vs 30.2%) and had lower mean IADL scores (6.2 vs 7.1, P < .001), whereas gender distribution and hypertension status did not differ significantly between groups.
Participants with less than senior high school education constituted a minority overall but were disproportionately represented among those who screened positive (Table 1). This pattern may indicate that the selected MMSE screening range is sensitive to identifying individuals from socially or educationally vulnerable groups who could benefit from further cognitive assessment. At the same time, it is well recognized that educational attainment can influence performance on cognitive screening tests. As educational level in this study was captured using broad attainment categories and may not fully reflect literacy, quality of schooling, or familiarity with test-taking, residual confounding and education-related differential performance cannot be entirely excluded. Accordingly, the screening-based prevalence estimates and associated sociodemographic patterns should be interpreted with caution.
Demographic Characteristics of Participants.
Note. P values were calculated using chi-square test or Fisher’s exact test (*) for categorical variables and independent-sample t-test for continuous variables.
MCI = mild cognitive impairment; DM = diabetes mellitus; HTN = hypertension; PA = physical activity; Lawton IADL = Lawton Instrumental Activities of Daily Living scale.
Univariate and Multivariate Analysis
In univariate analysis, older age, being unmarried, unstable income, lower education, reduced recreational engagement, and lower IADL scores were linked to higher odds of MCI (all P < .05). Variables with P < .25 were included in the multivariable model 28 ; hypertension and diabetes did not meet this criterion (Table 2).
Univariate and Multivariate Analysis of Factors Associated With MCI.
MCI = mild cognitive impairment; DM = diabetes mellitus; HTN = hypertension; PA = physical activity; Lawton IADL = Lawton Instrumental Activities of Daily Living scale.
Variables with P < .25 in univariate analyses were included in the multivariable model (age, gender, marital status, income, education, recreational activity, and IADL score), while hypertension and diabetes were assessed univariately.
In the adjusted model, age remained the dominant predictor (aOR = 1.25), with the odds increasing by roughly 25%/additional year. Being male (aOR = 0.20), married/cohabiting (aOR = 0.37), and financially stable (aOR = 0.33) were associated with lower odds of MCI.
Recreational activity exhibited a graded protective pattern. Participants engaging irregularly or regularly had 75% and 97% lower odds of MCI, respectively, compared with inactive peers. Likewise, each 1-point increase in Lawton IADL score reduced MCI odds by about 75% (aOR = 0.25). No multicollinearity was detected (VIF < 1.5), and the model showed good calibration (Hosmer-Lemeshow P = .23).
Discussion
This study demonstrates a high burden of screen-detected MCI among older outpatients, underscoring the intersection of cognitive vulnerability with social and functional factors. This study found that nearly 1 in 3 older outpatients in a secondary-level clinical setting screened positive for cognitive risk consistent with possible MCI. Age, gender, marital status, financial security, recreational activity, and functional capacity are associated with higher odds of MCI. Such findings confirm that cognitive vulnerability is common in clinical settings and strongly associated with social context.
The observed prevalence aligns with the upper range of estimates reported across Asia. A Thai urban community study using the Montreal Cognitive Assessment reported 33.9% prevalence among adults aged 30 to 65 years, 13 while a Myanmar study using the Revised Hasegawa’s Dementia Scale found 29.9% among those aged ≥60. 10 In contrast, a pooled Chinese meta-analysis of 41 community-based studies reported a lower prevalence of 12.2%, largely reflecting variations in diagnostic tools and age composition. 31 A Malaysian longitudinal study documented an incidence rate of 10.5/100 person-years among cognitively intact older adults over 1.5 years. 11 Within Vietnam, prevalence estimates have varied substantially across settings. A community-based survey in Hue City reported a prevalence of 28.2%, 12 whereas hospital-based studies have documented substantially higher proportions of mild cognitive impairment, including 43.4% among older outpatients screened with the MoCA and 51% among older hospital patients assessed using the MMSE.32,33 These differences likely reflect variations in study populations and recruitment settings, as hospital samples tend to include individuals seeking care for health concerns, including cognitive symptoms, rather than representing the general older population.
Older age was the strongest factor associated with impairment, with affected participants being on average 6 years older than those without impairment. This aligns with neurobiological evidence linking advancing age to cognitive decline. 34 In Vietnam, demographic shifts are amplifying this concern. A large cross-sectional study of 3500 older adults reported a sharp rise in cognitive symptoms after age 70, supporting the need for age-sensitive cognitive screening in geriatric care. 35
Social circumstances also influenced risk. Being married or cohabiting was protective, consistent with a Vietnamese cohort showing that individuals aged ≥60 living with both spouse and children had better cognitive performance than those living alone, suggesting a potential protective role of co-residence and familial support. 36
Conversely, participants reporting unstable income had nearly 3-fold higher odds of MCI. National surveys indicate that financial strain among older households in Vietnam contributes to delayed medical visits and reduced care access. 37 International evidence also links financial hardship to poorer diet quality and fewer cognitively stimulating activities, potentially reducing cognitive reserve. 38
Lifestyle engagement also differentiated cognitive risk. A dose-response pattern was observed, as even occasional recreational activity was associated with lower odds of impairment, while regular participation provided the greatest protection. This aligns with evidence that socially and cognitively stimulating activities enhance neural plasticity and slow decline. 39 Longitudinal data further indicate a bi-directional relationship, as participation both preserves cognition and is sustained by better cognitive function, forming a reinforcing cycle of resilience. 40
Functional limitations in IADLs were closely associated with MCI. Lower Lawton scores among affected individuals suggest that early deficits in managing complex daily tasks may signal progression toward dementia. 41 Yet, IADL performance is influenced by other domains such as mobility, balance, and sensory function. 42 Therefore, clinicians should interpret functional limitations within a multidimensional context.
Gender differences were apparent only after multivariable adjustment, with women showing greater risk of impairment. This pattern mirrors previous evidence and may reflect both biological and social factors.43,44 Biologically, faster hippocampal atrophy, greater amyloid-tau burden, and postmenopausal estrogen decline may heighten female vulnerability. 43 Socially, lower educational and occupational complexity among older women may compound risk. 44 These interpretations warrant caution. We did not measure reporting propensity or detailed life‑course exposures, 45 and the male-female health‑survival paradox may further complicate interpretation. 46
This study has several limitations. First, cognitive status was identified using the MMSE as a screening instrument rather than a diagnostic assessment, and screening-based classification may introduce some degree of misclassification. Although educational attainment was included as a covariate, the measure captured only broad schooling categories and may not fully reflect literacy, educational quality, or familiarity with cognitive testing, leaving the possibility of residual education-related variation in screening performance. Second, several contextual variables, including recreational activity and lifestyle-related factors, were assessed using structured interviewer-administered questions rather than standardized psychometric instruments, which may limit measurement precision. Third, the hospital-based sample and the exclusion of individuals with significant depressive symptoms, sensory impairments, or illiteracy may restrict generalizability to the broader older population. The cross-sectional design also precludes causal inference regarding the observed associations.
An additional methodological consideration relates to sample size planning. A formal sample size calculation was not performed prior to data collection. However, the final sample of 631 participants provides reasonable precision for estimating population proportions, allowing estimation with an approximate margin of error of ±4% at the 95% confidence level under a conservative prevalence assumption of 50%. This estimation is based on the standard formula for calculating sample size in studies aimed at estimating population proportions. Previous studies in Vietnam have reported MCI prevalence ranging from ~28% to 51% among older adults attending healthcare facilities, suggesting that the sample size in the present study falls within a reasonable range for investigating MCI in clinical settings.12,32,33
Conclusion
MCI affected nearly one-third of older outpatients and was strongly associated with age, social vulnerability, recreational inactivity, and functional decline. Integrating brief cognitive and social-functional screening into outpatient workflows may support earlier identification and more holistic geriatric care in Vietnam.
Supplemental Material
sj-docx-1-inq-10.1177_00469580261444222 – Supplemental material for Prevalence and Correlates of Mild Cognitive Impairment in Older Outpatients: A Cross-Sectional Study
Supplemental material, sj-docx-1-inq-10.1177_00469580261444222 for Prevalence and Correlates of Mild Cognitive Impairment in Older Outpatients: A Cross-Sectional Study by Khai Quang Nguyen, The Ha Ngoc Than and Kien Gia To in INQUIRY: The Journal of Health Care Organization, Provision, and Financing
Footnotes
Acknowledgements
The authors thank their colleagues at Nhan Dan Gia Dinh Hospital for their support during the study. We particularly acknowledge Hai Hoang Nguyen and Tan Vo Van for their administrative assistance with study implementation. We are also grateful to Ly Nguyen Ngoc Tran, Hang Thi Thuy Pham, Vinh Hoang Nguyen, and Yen Thi Hoang Do for their help with participant recruitment and data collection. The authors also thank all older adults and caregivers who participated in this study for their time and cooperation.
Ethical Considerations
The study was approved by the Biomedical Research Ethics Committee of the University of Medicine and Pharmacy at Ho Chi Minh City (reference number: 625/HĐĐĐ-ĐHYD, dated May 5, 2024) and by the Ethics Committee of Nhân Dân Gia Định Hospital (reference number: 65/NDGĐ-HĐĐĐ, dated May 17, 2024). The study adhered to the ethical principles outlined in the revised 1987 Declaration of Helsinki.
Consent to Participate
Written informed consent was provided by all participants.
Consent for Publication
This manuscript contains no individual person’s data in any form (including images, videos, or recordings). All data are de-identified and reported in aggregate; therefore, consent for publication was not required according to institutional policy.
Author Contributions
K.Q.N. and K.G.T. conceived and designed the study. K.Q.N. collected the data. K.Q.N. and K.G.T. analyzed and interpreted the data. K.Q.N., K.G.T., and T.H.N.T. drafted and critically revised the manuscript for important intellectual content. All authors read and approved the final version of the manuscript and agree to be accountable for all aspects of the work.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Data Availability Statement
The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request. A preprint version of this manuscript has been posted on medRxiv (doi:10.1101/2025.10.09.25337695).
Supplemental Material
Supplemental material for this article is available online.
References
Supplementary Material
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