Association Between Health Literacy and One-Year Incidence of Pre-Frailty Among Older Adults Undergoing Frailty Health Checkups

Objective: We aimed to identify predictors of the transition to pre-frailty among older adults undergoing frailty health checkups and to evaluate their relative importance. Methods: A longitudinal analysis was conducted using data from a frailty health checkup project involving 830 older adults participating in community exercise classes in Matsumoto City, Nagano Prefecture, Japan. Among them, 502 individuals classified as robust (healthy) at baseline were followed for 1 year. Predictors of transition to pre-frailty were examined using multivariate logistic regression analysis. Given the low follow-up rate (43.4%), a sensitivity analysis using inverse probability weighting (IPW) was performed. Model performance was internally validated using bootstrap resampling and calibration assessment. Results: Of the 218 participants who completed the follow-up period, 45 (20.6%) transitioned to pre-frailty. Increasing age was a significant risk factor (OR = 1.13, 95% CI: 1.06–1.20), whereas higher health literacy was a protective factor (OR = 0.51, 95% CI: 0.29–0.86). In the IPW sensitivity analysis, the association with age remained stable, while health literacy demonstrated borderline significance (p = 0.08). The model showed acceptable discrimination (area under the curve [AUC] = 0.737; 0.728 after optimism correction) and good calibration (Hosmer–Lemeshow test, p = 0.124). Conclusions: Age and health literacy were independent predictors of transition to pre-frailty. As a modifiable factor, health literacy may represent a promising target for interventions aimed at preventing the progression to pre-frailty.