Association between the uric acid-to-albumin ratio and risk of all-cause mortality in centenarians: a prospective cohort study.

Abstract

The uric acid-to-albumin ratio (UAR) has emerged as a potential composite biomarker reflecting oxidative stress and nutritional status, both of which are relevant to aging and mortality risk. However, its prognostic value in extremely long-lived individuals remains unclear. A prospective cohort study involving 1,002 centenarians from China Hainan was conducted between June 2014 and December 2016. Participants were followed for survival status through March 31, 2023. Restricted cubic spline (RCS) modeling, Cox proportional hazards regression, and Kaplan-Meier survival analyses were employed to assess the association between UAR and mortality risk. After excluding 78 centenarians, the cohort included 924 centenarians (median age: 102 years; 18.29% male). During a median follow-up of 29.70 months, 854 (92.42%) died. RCS analysis indicated a statistically significant overall association between UAR and mortality (adjusted P for overall = 0.009), with evidence of non-linearity (adjusted P for non-linearity = 0.029). In multivariable Cox regression analysis, individuals in the higher UAR quartile (Q4) demonstrated a 28.7% increased risk of mortality compared with those in the lower three quartiles (Q1-Q3) (adjusted hazard ratio: 1.287, 95% CI: 1.093,1.516; P = 0.003). Kaplan-Meier analysis further revealed that participants in Q4 had a significantly shorter median survival time (26 months) compared with those in Q1-Q3 (32 months) (log-rank test, P < 0.001). Elevated UAR is independently associated with increased all-cause mortality in centenarians, suggesting its potential utility as a prognostic biomarker for risk stratification in exceptionally long-lived populations.