Objective: To assess longitudinally the association of serum uric acid and its change due to diuretic treatment with cardiovascular events in hypertensive patients.
Design: Cohort study in a randomized trial.
Setting: Cohort of hypertensive patients.
Participants: A total of 4327 men and women, aged > or = 60 years, with isolated systolic hypertension, randomized to placebo or chlorthalidone, with the addition of atenolol or reserpine if needed, were observed for 5 years.
Main outcome measures: Major cardiovascular events, coronary events, stroke and all-cause mortality.
Results: Cardiovascular event rates for quartiles of baseline serum uric acid were: I, 32.7 per 1000 person-years; II, 34.5 per 1000 person-years; III, 38.1 per 1000 person-years; and IV, 41.4 per 1000 person-years (P for trend = 0.02). The adjusted hazard ratio (HR), of cardiovascular events for the highest quartile of serum uric acid versus the lowest quartile was 1.32 (95% CI, 1.03-1.69). The benefit of active treatment was not affected by baseline serum uric acid. After randomization, an increase of serum uric acid < 0.06 mmol/l (median change) in the active treatment group was associated with a HR of 0.58 (0.37-0.92) for coronary events compared with those with a serum uric acid increase > or = 0.06 mmol/l. This difference was not explained by blood pressure effects. Those with a serum uric acid increase > or = 0.06 mmol/l in the active treatment group had a similar risk of coronary events as the placebo group.
Conclusions: Serum uric acid independently predicts cardiovascular events in older persons with isolated systolic hypertension. Monitoring serum uric acid change during diuretic treatment may help to identify patients who will most benefit from treatment.