Claims-based Frailty Index in Japanese Older Adults: A Cohort Study Using LIFE Study Data

Abstract

Background: We aimed to assess whether the United States-developed Claims-based Frailty Index (CFI) can be implemented in Japanese older adults using claims data.

Methods: We used the monthly claims data and certification of long-term care (LTC) insurance data of residents from 12 municipalities from April 2014 to March 2019. The 12 months from first recording was defined as the “baseline period,” and the time thereafter as the “follow-up period”. Participants aged ≥65 years were included, and those with no certified LTC insurance or who died at baseline were excluded. New certification of LTC insurance and all-cause mortality during the follow-up period were defined as outcome events. CFI categorization consisted of three steps including: 1) using 12 months deficit-accumulation approach that assigned different weights to each of the 52 items; 2) the accumulated score to derive the CFI; and 3) categorizing the CFI as “robust” (<0.15), “prefrail” (0.15–0.24), and “frail” (≥0.25). Kaplan–Meier survival curves and Cox proportional hazard models were used to determine the association between CFI and outcomes. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated.

Results: There were 519,941 participants in total. After adjusting for covariates, the severe CFI category had a high risk of certification of LTC insurance (prefrail: HR 1.33; 95% CI, 1.27–1.39 and frail: HR 1.60; 95% CI, 1.53–1.68) and all-cause mortality (prefrail: HR 1.44; 95% CI, 1.29–1.60 and frail: HR 1.84; 95% CI, 1.66–2.05).

Conclusion: This study suggests that CFI can be implemented in Japanese claims data to predict the certification of LTC insurance and mortality.