journal articles
DECLINING KIDNEY FUNCTION AND FRAILTY PROGRESSION: A 7-YEAR COHORT STUDY OF CHINESE MIDDLE-AGED AND OLDER ADULTS
Fan Zhang, Yan Bai, Liuyan Huang, Yifei Zhong
BACKGROUND: This study aimed to investigate the association between baseline kidney function and frailty trajectories in middle-aged and older adults.
METHODS: Data were derived from the China Health and Retirement Longitudinal Study (2011–2018), including 5364 participants aged ≥45 years at baseline with up to four assessment waves over approximately 7 years. Kidney function was evaluated using estimated glomerular filtration rate based on serum creatinine and cystatin C (eGFRscr-cysc) and categorized as normal (≥90), mildly reduced (60–89) and moderately-to-severely reduced (<60 ml/min/1.73m²). Frailty was assessed using a 30‑item frailty index (0–100 scale). Linear mixed-effects models with random intercepts were used to examine the effects of baseline kidney function and its interaction with time on frailty index trajectories.
RESULTS: At baseline, the mean frailty index was higher in participants with mildly (β=2.28, 95% CI: 1.63–2.94) and moderately-to-severely (β=3.70, 95% CI: 2.41–4.99) reduced kidney function compared to normal kidney function, where β represents the adjusted difference in frailty index relative to the reference group. Frailty index increased over time in all groups; in participants with normal kidney function, it rose by 0.83 points per year (95% CI: 0.77–0.90). The annual increase was 0.26 points greater (95% CI: 0.18–0.35) in the mildly reduced and 0.70 points greater (95% CI: 0.54–0.87) in the moderately-to-severely reduced group. Over approximately 7 years, predicted mean frailty index increased from 15.1 to 20.9, 17.4 to 25.0, and 18.8 to 29.5 in the normal, mildly reduced and moderately-to-severely reduced groups, respectively.
CONCLUSIONS: Middle-aged and older adults with lower kidney function exhibited higher frailty index levels at baseline and faster frailty progression over time.
CITATION:
Fan Zhang ; Yan Bai ; Liuyan Huang ; Yifei Zhong (2025): Declining kidney function and frailty progression: a 7-year cohort study of Chinese middle-aged and older adults. The Journal of Frailty and Aging (JFA). https://doi.org/10.1016/j.tjfa.2026.100151