Long-term Care Insurance System Research Articles

Factors associated with malnutrition in demented and non-demented elderly residing in the community of Korea: a cross-sectional descriptive and analytical study

Objectives: This study aimed to investigate and compare factors associated with malnutrition according to the presence or absence of dementia in community-dwelling elderly people. Methods: Needs assessment data from 311 long-term care insurance (LTCI) recipients (dementia group 203; non-dementia group 108) that participated in the second pilot program of the integrated care model in community care settings under the Korean LTCI system were used. Descriptive statistical analysis, independent t-test, and analysis of variance were conducted on the sociodemographic characteristics, health and functional status, and nutritional status of the dementia and non-dementia groups. Logistic regression analysis was conducted to identify factors associated with malnutrition in the dementia and non-dementia groups. Results: Malnutrition occurred in 33.5% and 26.9% of participants in the dementia and non-dementia groups, respectively. In the dementia group, living with family rather than living alone (odds ratio [OR]: 3.81; 95% confidence interval [CI]: 1.50–9.66; P = 0.031), increase in Korean Activities of Daily Living (K-ADL) score (OR: 1.35; 95% CI: 1.17–1.55; P < 0.001), and increase in the Neuropsychiatric Inventory-Questionnaire score (OR: 1.02; 95% CI: 1.01–1.03; P = 0.005) were associated with a higher risk of malnutrition. In the non-dementia group, the risk of malnutrition increased as the K-ADL score increased (OR: 1.20; 95% CI: 1.04–1.39; P = 0.011) and in the depressed group (OR: 2.84; 95% CI: 1.04–7.74; P = 0.042).Conclusions: The study results confirmed the necessity of nutritional management for community-dwelling LTCI recipients. When developing a nutritional management program, considering the differences in factors related to malnutrition between the dementia and non-dementia groups is important. This study proposes policies for improving the LTCI system in terms of nutritional management and the utilization of community resources.

Developing a battery of physical performance tests to predict functional disability in Japanese older adults: A longitudinal study from the Kasama study.

Preventing functional disability benefits the quality of life of older adults and mitigates the economic burden of an aging society. However, the most effective physical performance tests and optimal cut points for identifying older adults at risk of functional disability remain unclear, and Japan lacks physical function-based assessment tools. We aimed to identify the physical performance tests related to functional disability and to develop a predictive test battery for it. We included 975 older adults (mean 72.8 ± 5.2 years, 55.4% women) in Kasama City, Japan. Functional disability was defined as certification of care level 2 or above based on the long-term care insurance system. Cox proportional hazards analysis examined the association between physical performance tests and incident functional disability. During a mean follow-up of 8.6 years (maximum 14 years), 236 participants (24.2%) developed functional disability. After adjusting for covariates, higher performances in grip strength, single-leg balance with eyes open (SLB), timed up-and-go (TUG), five-repetition sit-to-stand (5-STS), and 5-m habitual walk were significantly associated with a lower risk of functional disability. In a stepwise model, SLB, TUG, and 5-STS were key predictors of functional disability. Receiver operating characteristic analysis determined optimal cut points of 32.6/32.7 s for SLB, 6.5/6.6 s for TUG, and 7.8/7.9 s for 5-STS. We developed a predictive battery combining these cut points (area under the curve = 0.78). The developed battery of physical performance tests predicts future functional disability and is useful for screening older adults at high risk. Geriatr Gerontol Int 2024; ••: ••-••.

Long-Term Care in Germany in the Context of the Demographic Transition—An Outlook for the Expenses of Long-Term Care Insurance through 2050

Demographic aging results in a growing number of older people in need of care in many regions all over the world. Germany has witnessed steady population aging for decades, prompting policymakers and other stakeholders to discuss how to fulfill the rapidly growing demand for care workers and finance the rising costs of long-term care. Informed decisions on this matter to ensure the sustainability of the statutory long-term care insurance system require reliable knowledge of the associated future costs. These need to be simulated based on well-designed forecast models that holistically include the complexity of the forecast problem, namely the demographic transition, epidemiological trends, concrete demand for and supply of specific care services, and the respective costs. Care risks heavily depend on demographics, both in absolute terms and according to severity. The number of persons in need of care, disaggregated by severity of disability, in turn, is the main driver of the remuneration that is paid by long-term care insurance. Therefore, detailed forecasts of the population and care rates are important ingredients for forecasts of long-term care insurance expenditures. We present a novel approach based on a stochastic demographic cohort-component approach that includes trends in age- and sex-specific care rates and the demand for specific care services, given changing preferences over the life course. The model is executed for Germany until the year 2050 as a case study.

Housing Adaptations and Long-Term Care Facility Admissions among Older Adults with Care Needs in Japan

ObjectivesHousing adaptations may contribute to aging in place for older adults with care needs by reducing the risk of long-term care facility (LTCF) admissions, but this association remains unclear. We examined the association between housing adaptations and LTCF admissions among older adults with care needs. DesignRetrospective cohort study using data from a Japanese municipality. Setting/ParticipantsAdults aged ≥65 years who were newly certified with care needs under the public long-term care insurance system between April 2014 and March 2016. MethodsThe study exposure was the implementation of insurance-covered housing adaptations (maximum covered cost: ¥200,000) during the 2 years after certification. Based on this exposure, participants were assigned to a non-implementation group (no housing adaptations), sub-maximum cost group (housing adaptations below the maximum cost), or maximum cost group (housing adaptations at the maximum cost). A Fine-Gray subdistribution hazards model was used to analyze the associations between the exposure groups and new LTCF admissions after adjusting for various risk factors. Death was regarded as a competing risk, and participants were followed until March 2022. ResultsAmong 4610 participants, 1261 (27.3%) had implemented housing adaptations. Among these, 943 (74.8%) were in the sub-maximum cost group and 318 (25.2%) were in the maximum cost group. During the follow-up period (median: 51 months), the incidence of LTCF admission was 3.9/1000 person-months in the non-implementation group, 3.8/1000 person-months in the sub-maximum cost group, and 2.8/1000 person-months in the maximum cost group. The adjusted subdistribution hazard ratio of LTCF admission (reference: non-implementation) was 0.90 (95% CI: 0.75–1.08) for the sub-maximum cost group and 0.67 (0.49–0.93) for the maximum cost group. Conclusions and ImplicationsHousing adaptations can support aging in place for older adults with care needs. Health care professionals and policymakers should consider the suitability of housing environments to reduce the risk of institutionalization.

Development of a practical framework and indicators for monitoring integrated long-term health and care needs and service use

This case study presents an evidence-building approach to support policy planning for integrated health and care delivery for older adults. We developed an integrated needs-assessment framework to monitor the complex long-term medical and care needs of older individuals, using routinely collected, standardized needs-assessment and utilization data from the public health and long-term care (LTC) insurance systems in South Korea. We also developed a set of misuse indicators and analyzed service utilization patterns, while accounting for their varying types of needs. Approximately 11 % of older Koreans were identified as having complex long-term medical and care needs, which were categorized into four distinct need groups. More than one-third of those in the higher-medical/lower-care needs group stayed in LTC hospitals for six months or more during the year, and about one-third of those in the higher-medical/higher-care needs group inappropriately resided in LTC facilities, where medical services are limited. The newly developed integrated needs-assessment framework and misuse indicator set provide practical tools for monitoring the extent and nature of complex needs, as well as patterns of over- or under-utilization of health and care services over time. The empirical evidence gathered here highlights the need for reforms in South Korea's health and LTC systems.

Prevalence and Prognostic Impact of Multiple Frailty Domain in Japanese Older Adults

ObjectivesIn this observational study, we aimed to evaluate the independent and overlapping effects of multiple frailty domains on long-term care insurance (LTCI) use. DesignPopulation-based cohort design. Setting and ParticipantsIn total, 9804 community-dwelling older adults were recruited from the National Center for Geriatrics and Gerontology-Study of Geriatric Syndromes. MethodsThe physical domain of frailty was assessed using the revised Japanese version of the Cardiovascular Health Study criteria. The cognitive domain of frailty was identified as impairment of memory, attention, executive function, or processing speed using standardized thresholds established for each domain in population-based cohorts. The social domain was operationalized using the National Center for Geriatrics and Gerontology-Social Frailty Scale. The use of LTCI was prospectively determined over 60 months using data extracted from the Japanese long-term care insurance system. ResultsThe data from 7745 participants were analyzed, of whom 793 (10.2%) required LTCI certification within 60 months (interquartile range: 60–60 months). The Kaplan–Meier curve analysis demonstrated that a high number of frailty domains was associated with incident LTCI use. The proportions of incident LTCI use were 6.0%, 12.4%, 30.1%, and 43.9% for non-frail participants and those with impairments in 1, 2, and 3 frailty domains, respectively. In the multivariate Cox regression model, physical, cognitive, and social domain impairments independently increased the risk of incident LTCI use [physical domain impairment, hazard ratio (HR), 1.67; 95% CI, 1.39–2.01; cognitive domain impairment, HR, 1.59; 95% CI, 1.37–1.84; social domain impairment, HR, 1.26; 95% CI, 1.05–1.50]. Conclusions and ImplicationsOverlapping frailty domains were strongly associated with incident LTCI use among community-dwelling older adults. These findings emphasize the importance of assessing multiple frailty domains and tailoring interventions according to the unique circumstances of older adults to prevent functional disabilities.

Can long-term care insurance prevent worsening of frailty among older Chinese adults? A difference-in-differences study based on CHARLS data

Frailty, which is accompanied by negative health outcomes associated with aging, is an increasingly serious public health problem. Long-term care insurance (LTCI) is an effective intervention for frailty in older adults, but few studies have linked LTCI to frailty prevention. This study aimed to determine the role of LTCI in preventing worsening of frailty in older adults. This study used five-wave panel data from the China Health and Retirement Longitudinal Study (CHARLS) 2011 to 2020 to construct an indicator system to assess the frailty index (FI) of surveyed older adults and used a difference-in-differences (DID) method to assess the policy effect of LTCI on frailty among older adults. We found that the full-sample mean of the FI of older adults in China was 0.196, and the implementation of LTCI had a significant negative effect on the FI of older adults. The effect was heterogeneous across sex, age, education and medical insurance groups. LTCI had a more significant negative effect on male group, the middle-aged group, the less educated group, and the URRBMI group, while the effect was less significant for the female and the UEBMI group, and not significant for the more educated and other age groups. That is to say, older Chinese adults are generally frail to different degrees, and the implementation of a LTCI system can prevent worsening of frailty among them, but the effect is not equal across populations. The institutional coverage of LTCI should be further strengthened in the future to slow down the frailty process of the enrollees, so as to promote healthy aging.

Policy Issues and Prospects for the Development of China's Long-term Care Insurance System: Taking Shanghai as an Example

Policy Issues and Prospects for the Development of China's Long-term Care Insurance System: Taking Shanghai as an Example

Effectiveness of Japan’s Health Insurance System in Meeting Complex Long-Term Care Needs

Japan’s Long-Term Care Insurance (LTCI) system, introduced in 2000, was designed to address the growing needs of the country’s aging population. This study evaluates the effectiveness of the LTCI system in meeting complex long-term care needs, focusing on four key dimensions: access, quality, financial sustainability, and user satisfaction. Using quantitative analysis of data from national databases and surveys, the study reveals significant improvements in access to services and positive care outcomes, with approximately 80% of beneficiaries expressing satisfaction with the services received. However, geographic disparities persist, with rural areas facing limited service availability compared to urban centers. Financial sustainability remains a critical concern, as expenditures have risen by 20% over the past five years, highlighting the need for innovative funding models. The study recommends policy interventions to address regional disparities, ensure financial viability, and expand specialized services for individuals with complex care needs. By examining these challenges and opportunities, the study provides insights into the strengths and limitations of the LTCI system and offers guidance for future policy development. The findings underscore the importance of targeted reforms to enhance the system’s capacity to deliver high-quality, equitable care to Japan’s elderly population.

Last year of life care transitions between long-term care insurance services in Japan: Analysis of long-term care insurance claims data.

We determined the number of care transitions in the year before death among older adults requiring long-term care (LTC) and those receiving public LTC insurance (LTCI) services in Japan, along with care transition pathways and factors associated with the number of care transitions. This study used data from the Japanese LTCI claims, which store national information on certification of needed LTC and LTCI claims data. Services received in the year before death were classified as in-home, facility, mixture of in-home and facility, and not using LTCI services. The transition count is presented, and Sankey diagrams are produced to visualize care transition pathways. We used a multivariable analysis to identify factors associated with the number of care transitions. Of the participants, 276 896 (65.2%) experienced at least one transition in LTCI care settings in the year before death. Further, 72.0% of those requiring mild LTC underwent one or more transitions. Participants who were 75-84 years old (vs. 65-74 years old), male, without medical care needs, with symptoms of dementia, and with changes in LTC needs in the year before death were more likely to require care transitions. Moreover, participants with higher baseline LTC needs were less likely to require transitions. Over half the participants requiring LTC underwent one or more care transitions in the year before death. Policy deliberations regarding enhancing care under the LTCI system at the end of life and optimizing care transitions are necessary. Geriatr Gerontol Int 2024; ••: ••-••.

Observational study of frailty in older Japanese patients with non-valvular atrial fibrillation receiving anticoagulation therapy

The number of patients with atrial fibrillation is increasing, and frailty prevalence increases with age, posing challenges for physicians in prescribing anticoagulants to such patients because of possible harm. The effects of frailty on anticoagulant therapy in older Japanese patients with nonvalvular atrial fibrillation (NVAF) are unclear. Herein, we prescribed rivaroxaban to Japanese patients with NVAF and monitored for a mean of 2.0 years. The primary endpoint was stroke or systemic embolism. The secondary endpoints were all-cause or cardiovascular death, composite endpoint, and major or non-major bleeding. Frailty was assessed using the Japanese long-term care insurance system. A multiple imputation technique was used for missing data. The propensity score (PS) was obtained to estimate the treatment effect of frailty and was used to create two PS-matched groups. Overall, 5717 older patients had NVAF (mean age: 73.9 years), 485 (8.5%) were classified as frail. After PS matching, background characteristics were well-balanced between the groups. Rivaroxaban dosages were 10 and 15 mg/day for approximately 80% and the remaining patients, respectively. Frailty was not associated with the primary endpoint or secondary endpoints. In conclusion, frailty does not affect the effectiveness or safety of rivaroxaban anticoagulant therapy in older Japanese patients with NVAF.Trial registration: UMIN000019135, NCT02633982.

Combined effects of loneliness and diabetes mellitus on disability incidence among older Japanese adults

BackgroundDeveloped countries worldwide face the challenge of aging populations in which loneliness is problematic, leading to mental and physical health issues. Diabetes mellitus (DM) can cause decreased physical activity, reduced functioning, and depressive symptoms. However, how interactions between loneliness and DM influence health outcomes remains unclear. We aimed to determine the effects of loneliness and DM-related complications on the incidence of disability among older individuals. MethodsWe analyzed data from the Japanese National Center for Geriatrics and Gerontology Study of Geriatric Syndromes for community-dwelling adults aged ≥65 years without initial long-term care needs. Loneliness was assessed using the University of California Los Angeles Loneliness Scale, and DM status was determined based on medical history obtained through face-to-face interviews. Disability incidence was identified by monthly tracking of certifications under the Japanese long-term care insurance system. The combined effect of DM and loneliness on care needs was examined using Cox proportional hazard regression models. ResultsAmong 5,160 participants, 298 (5.8 %) developed incident disabilities within 24 months. Cox models adjusted for potential confounders revealed a significantly increased disability risk among persons with DM and loneliness. Having DM without loneliness and vice versa were not significant risk factors for disability incidence compared with having neither. ConclusionsThe combination of loneliness with DM was a risk factor for disability development among community-dwelling older adults. Loneliness and DM might be interrelated and associated with disability development, suggesting that support along with assessments of mental health and illness might help to avoid disability in this population.

Effect of Early Rehabilitation Services After Discharge on Social Activity Among Chronic Stroke Survivors: A Multicenter Prospective Study

BackgroundSocial inactivity after a stroke leads to adverse outcomes, making social activity after discharge important for chronic stroke survivors. ObjectivesTo investigate the effects of early rehabilitation services after discharge on social activity among chronic stroke survivors. MethodsThe participants were prospectively recruited from three convalescent hospitals. Receipt of early rehabilitation services after discharge for chronic stroke survivors was defined as the utilization of day care or home-based rehabilitation services by the Japanese long-term care insurance system. Social activity was assessed using the Frenchay Activities Index (FAI) premorbid and at 3, 6, and 12 months after discharge. In this study, the outcome was defined as the change in the FAI score from 3 to 12 months after discharge. Multivariate regression analysis was performed to examine the effect of access to rehabilitation on changes in FAI. ResultsNinety stroke survivors (age 67.2 ± 11.6 years, 52 male) were enrolled. The FAI showed improvements by 27.4% and 1.4% from 3 to 12 months after discharge in the rehabilitation and non-rehabilitation groups, respectively. Multivariate regression analysis showed that access to rehabilitation after discharge was positively associated with the FAI change from 3 to 12 months after discharge (B = 30.3, β = 0.38, 95% confidence interval = 11.13–49.47, p = 0.002). ConclusionEarly rehabilitation services after discharge were significantly associated with increased social activity.

Changes in physical activity during the year after the Great East Japan Earthquake and future frailty in older survivors.

This study examines whether changes in physical activity (PA) during the first year after the Great East Japan Earthquake and Tsunami (2011-2012) contributed to preventing the onset of future frailty among older survivors of the disaster. This study tracked 2561 physically active Japanese survivors aged ≥ 65 years (43.6% men; mean age 72.9 years) who had completed self-administered questionnaires in 2011 and 2012. PA levels for participants were classified into four categories based on ≥23 and <23 metabolic equivalent hours/week in 2011 and 2012: "consistently low," "decreasing," "increasing," and "consistently high." Frailty was defined as a Kihon Checklist score ≥ 5, which is used in the long-term care insurance system in Japan. Hazard ratios were calculated for the onset of frailty using a Cox proportional hazards model that fitted the proportional sub-distribution hazards regression model with weights for competing risks of death. From 2012 to 2018, 283 men and 490 women developed frailty. Men with consistently high or increasing PA during the first year after the disaster had a lower risk of frailty. Furthermore, even increasing PA by walking for just 30 min/day prevented future frailty in men; however, this association between a change in PA and the decreased risk of frailty was not observed in women. Older men who remained physically active or resumed PA at an early stage and at a low intensity, even after being physically inactive owing to the disaster, were able to prevent future frailty. Geriatr Gerontol Int 2024; 24: 563-570.

A Study on the Sufficiency and Desired Needs of Long-term Care Insurance System for the Elderly - Focusing on Service Users

A Study on the Sufficiency and Desired Needs of Long-term Care Insurance System for the Elderly - Focusing on Service Users

Dose-response associations between physical activity and sedentary time with functional disability in older adults with or without frailty: a prospective cohort study.

Evidence regarding the dose-response curve shapes of physical activity (PA) and sedentary time (ST) in older adults with functional disability (FD) is extremely limited. Moreover, these associations may differ depending on with/without frailty. We examined the dose-response associations between moderate-to-vigorous PA (MVPA) and ST with FD among older adults with/without frailty. We included 7,480 initially nondisabled adults (3,795 men and 3,685 women) aged 65-84 years in Ota City, Tokyo, Japan. MVPA and ST were evaluated using the International Physical Activity Questionnaire-Short Form. FD was prospectively identified using a nationally unified database of the long-term care insurance system. Frailty was determined using Check-List 15, validated against Fried's frailty criteria. Multivariate-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of MVPA and ST for FD were calculated, and dose-response curves were examined using restricted cubic splines. During 3.6 years of follow-up, 1,001 (13.4%) participants had FD. Among all participants, compared with no MVPA, the HRs for FD reduced linearly up to approximately 2000 metabolic equivalents (METs)■min/week of MVPA, and the lowest HR (HR: 0.61, 95% CI: 0.51-0.74) was reached at around 3,000-4,000 METs■min/week. Although the shape of this association was consistent regardless of with/without frailty, the magnitude of the association tended to be stronger in frail older adults than in non-frail older adults. Compared with those for the median (300 min/day) of ST, the HRs for FD increased linearly as ST reached approximately 600 min/day or more, independent of MVPA, with a maximum HR of 1.31 (95% CI: 1.01-1.71) for 1,080 min/day among all participants. This association was more pronounced among non-frail older adults but not statistically significant among frail older adults. Higher MVPA levels consistently reduced the incidence of FD regardless of frailty in a significant inverse nonlinear dose-response manner. A significant positive nonlinear dose-response association between ST and FD risk was identified among non-frail older adults but not among frail older adults. Increasing MVPA and reducing prolonged ST are important for preventing FD among non-frail older adults. However, reducing ST alone may be insufficient; increasing MVPA, even if by only small increments, is highly recommended for frail older adults.

Factors Contributing to Health Deterioration in the Japanese Long-Term Care Insurance System in Terms of Instrumental Activities of Daily Living

This study aimed to determine which instrumental activities of daily living (IADL) are associated with health deterioration from the “support level” to the “care level” among users of the long-term care insurance system in Japan. From April 2017 to March 2020, we conducted a retrospective follow-up survey on 178 Japanese community-dwelling older adults (64 men, 114 women) newly certified as support level. Independent variable was 8 IADL items and the outcome defined as the “support level maintenance time.” Cox models were used to assess the risk of health deterioration, with adjustments for age group, family composition, dementia status, and frailty status by gender. Dependence on 5 items, “laundry” (hazard ratio [HR] =2.5; 95% confidence interval [CI]: 1.1-5.8), “cooking” (HR = 3.7; 95% CI: 1.1-12.2), “telephone use” (HR = 2.4; 95% CI: 1.2-4.7), “financial management” (HR = 2.5; 95% CI: 1.2-5.0), and “medication management” (HR = 2.4; 95% CI: 1.2-4.8), was independently associated with a worse outcome among men, whereas dependence on “financial management” (HR = 2.6; 95% CI: 1.5-4.7) and “medication management” (HR = 2.0; 95% CI: 1.1-3.5) was independently associated with a worse outcome among women. These findings suggest that difficulties in “financial management” and “medication management” are common factors associated with health deterioration from the support to the care level among both genders. An association with household tasks was also seen among men, indicating that a paradigm shift is needed to increase the participation of men in household tasks.

Evaluation of China's long-term care insurance policies.

In response to the increasing demand for long-term care services for older people, the Chinese government has launched a pilot program for long-term care insurance (LTCI) since 2016. The objective of this study is to evaluate the performance and effectiveness of this program in China and provide recommendations for the future development and expansion of the LTCI system. We developed a comprehensive evaluation framework to assess these LTCI policies implemented in all 49 pilot cities in China. Based on our evaluation, the average assessment score for the LTCI program across all pilot cities was 71.8 points, with scores ranging from 57.5 to 92.5 points in these cities. Furthermore, most of the pilot cities achieved higher scores in the fact-based assessment compared to the value-based assessment. The results suggested that the overall pilot effect regarding LTCI was favorable, but there were significant regional disparities. Moreover, in most of pilot cities, current LTCI policies were designed to alleviate both the financial burden and the burden of caring for people with disabilities that families faced. However, some challenges still remained, such as the lack of community and home-based care services, the need to expand the coverage of insurance, and the importance of diversifying funding sources.

The impact of reducing formal care benefits on caregivers’ well-being: evidence from Japan

AbstractThis study examines the impact of reducing formal care benefits on the well-being of informal caregivers, contributing to the ongoing discourse about establishing sustainable and adequate levels of formal care. We utilize a reform introduced in Japan’s public long-term care insurance system, which curtailed formal care benefits for a group of recipients with low care needs. Employing a difference-in-difference approach with fixed effects on a nationally representative sample of coresident informal caregivers, we explore both the overall and temporal effects of this reform. Our findings reveal that the reform had an adverse impact on caregivers’ physical well-being, leading to diminished mobility and stability. The impact on caregivers’ mental well-being was less clear, reflecting a competing influence of stress and the psychological rewards associated with caregiving. The decline in physical well-being endured over time, while the effects on mental well-being were transient. Additionally, female caregivers exhibited greater vulnerability compared to their male counterparts, experiencing more significant deterioration in both physical and mental well-being. Alarmingly, the reform also negatively influenced the well-being of care recipients, suggesting that reducing formal care benefits does not yield positive outcomes for either caregivers or recipients. This study underscores the necessity of accounting for caregivers’ well-being when evaluating the cost-effectiveness of reducing formal care benefits and advocates for policies aimed at safeguarding female caregivers from health and financial challenges.

Development of a weighted scoring model for social activities to predict disability incidents among older Japanese adults

BackgroundSocial activities contribute to health improvements in older adults, but methods for evaluating these activities are not yet established. We developed a scoring model for social activity, weighted by specific activities, to assess the association between disability incidence in older adults and social activities. MethodsData were obtained from Japan's National Center for Geriatrics and Gerontology Study of Geriatric Syndromes (NCGG-SGS). Social activity was evaluated across 16 domains. Disability was determined using data extracted from Japan's long-term care insurance system. ResultsData from 4998 older adults were analyzed; among them, 422 (8.4 %) developed a disability within 35 months (Interquartile range: 32-39). The Cox proportional hazards model was used to assess 16 domains of social activity. The results yielded risk factors for disability incidence in six social activity domains: work, travel, hobbies, babysitting, family caregiving, and events. The coefficients for these activities were assigned weights of 3, 3, 2, 1, 1, and 1, respectively. The weighted social activity scoring model significantly improved the ability to predict disability incidence when the number of social activities in which individuals participated was considered (social activity score: area under the curve [AUC] 0.691, 95 % confidence interval [CI] 0.664–0.717; number of social activities: AUC 0.681, 95 % CI 0.654–0.707, P = 0.042). ConclusionsThe composite score derived from the weighted social activity scoring model serves as a valuable tool due to its enhanced predictability, which complements established background factors associated with the incidence of disability in older adults.