Association between self-reported weight loss and new long-term care insurance certifications: A 9-year Japanese older adult cohort study.

Aim: This cohort study aimed to assess weight loss associated with new long-term care insurance (LTCI) certifications over a 9-year period, accounting for the competing risk of death.

Methods: We analyzed data from 3749 Japanese individuals aged ≥65 years in Kami Town, Hyogo Prefecture, Japan. Weight loss was assessed using the Kihon Checklist during the baseline survey. Data regarding LTCI certifications were collected until March 2022. Cox proportional hazards models were used to calculate adjusted hazard ratios (HRs) of 9-year LTCI certification because of weight loss, adjusted for confounding factors. To exclude the effect of competing risks, Fine-Gray regression was used to estimate subdistribution HRs. Subgroup analyses were carried out after the examination of potential interactions between subjective cognitive function, body mass index categories and weight loss.

Results: The incidence rate of new LTCI certifications was 5.16 per 100 person-years overall - broken down into 7.02 for those with weight loss and 4.97 for those without. The adjusted HR for weight loss to new LTCI certifications was 1.35 (95% CI 1.15-1.59). Considering mortality as a competing risk, the adjusted subdistribution HR was 1.37 (95% CI 1.16-1.61). Conversely, no interaction was observed between weight loss and subjective cognitive function or body mass index categories.

Conclusions: Excluding the effect of mortality, weight loss was identified as a risk factor for new LTCI certifications. However, no interaction was observed between weight loss and subjective cognitive function or body mass index categories. Geriatr Gerontol Int 2024; 24: 1320-1327.