Gout, not induced by diuretics? A case-control study from primary care

Background: It is taken for granted that diuretics may induce gout, but there is a general lack of evidence on this topic. Objectives: To determine the incidence of gout in patients who use diuretics, taking into account concurrent hypertension and cardiovascular diseases. Methods: A case-control study was designed. From a primary care population all patients with a first gout registration ( 59 men, 11 women; mean ( SD) age 55.1 ( 13.5)) were identified as cases. To relate the occurrence of gout to diuretic use a matched reference series of three controls for each case was compiled. Conditional logistic regression analyses were applied to estimate incidence rate ratios ( IRRs) of gout, and 95% confidence intervals ( CIs), in subjects with and without diuretic treatment, hypertension, and cardiovasculardiseases. Additional stratification analyses were made, particularly in the subjects not using diuretics. Results: The IRRs of gout in subjects with v those without diuretic treatment, hypertension, heart failure, and myocardial infarction were 2.8 ( 95% CI 1.2 to 6.6), 2.6 ( 95% CI 1.2 to 5.6), 20.9 ( 95% CI 2.5 to 173.8), and 1.9 ( 95% CI 0.7 to 4.7), respectively. After adjustment, the IRR of gout for diuretic use dropped to 0.6 ( 95% CI 0.2 to 2.0), while the IRRs of gout for hypertension, heart failure, and myocardial infarction were still > 1. This was also the case for subjects with hypertension or myocardial infarction, who had not used diuretics. Conclusion: The results suggest that diuretics do not actually increase the risk of gout. Cardiovascular indications for treatment may have confounded previous inferences.