Uric acid is not an independent predictor of cardiovascular mortality in type 2 diabetes: a population-based study

OBJECTIVE: Although some studies have suggested that uric acid is a risk factor for mortality, this relationship is still uncertain in people with type 2 diabetes. METHODS: The study base was the population-based cohort of 1540 diabetic subjects (median age 68.9 years) of the Casale Monferrato Study. The role of serum uric acid on 15-years all-cause, cardiovascular and non-cardiovascular mortality was assessed by multivariate Cox proportional hazards modeling. RESULTS: Baseline levels of serum uric acid were negatively correlated with HbA1c, were higher in men and in the elderly and were independently associated with components of the metabolic syndrome. Out of 14,179 person-years, 1000 deaths (514 due to cardiovascular diseases) were observed. Compared to the lower quartile of uric acid, HRs (95% CI) in the upper quartile were 1.47 (1.22-1.76) for all-cause mortality; 1.40 (1.09-1.80) for cardiovascular mortality and 1.50 (1.15-1.96) for non-cardiovascular mortality. In multiple adjusted models, however, HRs were 1.30 (1.06-1.60) for all-cause mortality, 1.13 (0.85-1.50) for cardiovascular mortality and 1.50 (1.11-2.02) for non-cardiovascular mortality (men 1.87, 1.19-2.95; women 1.20, 0.80-1.80); the latter appeared to be due to neoplastic diseases (HR in all combined quartiles vs. lower quartile: both sexes 1.59, 1.05-2.40; men 1.54, 0.83-2.84, women 1.68, 0.95-2.92). CONCLUSIONS: In diabetic people, uric acid is associated with components of the metabolic syndrome but it may not be accounted as an independent risk factor for cardiovascular mortality. The increased all-cause mortality risk with higher levels of uric acid might be due to increased neoplastic mortality and deserves future studies