Diuretic use, increased serum urate levels, and risk of incident gout in a population-based study of adults with hypertension: the Atherosclerosis Risk in Communities cohort study.

OBJECTIVE: To quantify the role of diuretic use in gout development in an adult population with hypertension.

METHODS: The Atherosclerosis Risk in Communities study, a prospective population-based cohort from 4 US communities, consisted of 4 visits over a 9-year period. Participants were included in this analysis if they answered a query about gout, were free of gout at baseline, and had hypertension (defined as taking medication to treat hypertension or having blood pressure of ≥140/90 mm Hg). Trained interviewers recorded use of antihypertensive drugs. Incident gout was defined as self-reported onset of gout after baseline. Using a time-dependent Cox proportional hazards model, we estimated hazard ratios (HRs; with 95% confidence intervals [95% CIs]) for incident gout by time-varying diuretic use, both adjusted for confounders and tested for mediation by serum urate level.

RESULTS: There were 5,789 participants with hypertension; 37% were treated with a diuretic. Use of any diuretic (HR 1.48 [95% CI 1.11, 1.98]), a thiazide diuretic (HR 1.44 [95% CI 1.00, 2.10]), or a loop diuretic (HR 2.31 [95% CI 1.36, 3.91]) was associated with incident gout as compared with not using any diuretic, not using a thiazide diuretic, or not using a loop diuretic, respectively. After adjusting for serum urate level, the association between diuretic use and gout was null. Use of antihypertensive medication other than diuretic agents was associated with decreased gout risk (adjusted HR 0.64 [95% CI 0.49, 0.86]) compared to untreated hypertension. The longitudinal change in serum urate levels was 0.72 mg/dl (95% CI 0.57, 0.87) higher in those who began treatment with a diuretic than in those who did not (P<0.001).

CONCLUSION: Thiazide and loop diuretics were associated with increased gout risk, an association mediated by a change in serum urate levels.