Testosterone modifies U-Shaped association of eGFR with all-cause mortality in Chinese female centenarians: a prospective cohort study

BACKGROUND: The relationship between kidney function and mortality in centenarians, particularly with respect to hormonal regulation, remains unclear. This study investigated the association between estimated glomerular filtration rate (eGFR) and all-cause mortality in female centenarians and explored the potential role of testosterone. METHODS: Within the China Hainan Centenarian Cohort Study, 701 female centenarians (median age: 102 years) were enrolled. eGFR was calculated using the CKD-EPI 2009 creatinine equation. Restricted cubic splines (RCSs) and multivariable Cox proportional hazards models were employed to assess nonlinear associations. Likelihood ratio tests were used to evaluate the interaction effect of testosterone. RESULTS: During a median follow-up of 31 months, 643 participants (91.7%) died. RCS analysis revealed a significant nonlinear association (P-overall < 0.001; P-nonlinear = 0.004) between eGFR and all-cause mortality, characterized by a U-shaped curve, with an inflection point of 60.65 mL/min/1.73 m² identified in the adjusted RCS model. Multivariable-adjusted Cox regression analysis showed that each 10-mL/min/1.73 m² increase in eGFR was associated with a 6.8% reduction in all-cause mortality risk (hazard ratio = 0.932, 95% confidence interval: 0.882-0.985, P = 0.012). Compared with centenarians with eGFRs of 45-