Uric acid within the "normal" range predict 9-year cardiovascular mortality in older individuals. The InCHIANTI study

Abstract

Background and aims: Increased uric acid levels correlate with cardiovascular disease and cardiovascular/overall mortality. To identify a uric acid threshold above which cardiovascular mortality rises, we studied the relationship between uric acid concentration and overall/cardiovascular mortality.

Methods and results: We analyzed data from the InCHIANTI study, a cohort study of Italian community-dwelling people with 9 years of follow-up. We selected a sample of 947 individuals over 64 years of age, free from cardio-cerebrovascular disease and with available uric acid measurement at baseline. The sample was divided according to plasma uric acid tertiles. The Hazard ratio (HR) for mortality was calculated by multivariate Cox proportional hazard model. Mean age of participants was 75.3 ± 7.3 years; the mean value of uric acid was 5.1 ± 1.4 mg/dl. Over 9-years of follow-up, 342 (36.1%) participants died, 143 deaths (15.1%) were due to cardiovascular disease. Subjects with higher uric acid concentrations presented a higher cardiovascular mortality [II (4.6-5.5 mg/dl) vs I (1.8-4.5 mg/dl) tertile HR: 1.98, 95%C.I. 1.22-3.23; III (≥5.6 mg/dl) vs I tertile HR: 1.87, 95%C.I. 1.13-3.09]. We found a non-linear association between uric acid concentrations and cardiovascular mortality with the lowest mortality for values of about 4.1 mg/dl and a significant risk increment for values above 4.3 mg/dl.

Conclusion: In community-dwelling older individuals free from cardio-cerebrovascular events, the lowest 9-year cardiovascular mortality was observed for uric acid values far below current target values. If confirmed, these data might represent the background for investigating the efficacy of uric acid levels reduction in similar populations.

Keywords: Cardiovascular mortality; Community-dwelling; Elderly; InCHIANTI study; Mortality; Uric acid.