Risk of acute gout among active smokers: data from nationwide inpatient sample

Smoking has been found to be negatively correlated with serum uric acid levels by virtue of reduced production and increased consumption of endogenous antioxidant uric acid among smokers and has been reported to decrease incidence of gout. To shed further light on the question of association between active smoking and acute gout by examining this association using a large inpatient US database, using the Nationwide Inpatient Sample data from 2009 to 2011, we identified current smokers based on the International Classification of Diseases, Ninth Revision (ICD-9) code 305.1 and were assumed to have ceased smoking during hospital stay. Patients who developed acute gout inhospital were identified based on ICD-9 code 274.01 at secondary diagnosis position. Univariate and multivariate logistic regressions were used to derive odds ratio for measures of association. Statistical analysis was done using STATA version 13.0 (College Station, TX). A total of 17,847,045 discharge records were used which included 13,932 (0.08 %) inhospital acute gouty arthritis and 2,615,944 (14.66 %) active smokers. Both univariate (OR 0.59, CI 0.54-0.63, p < 0.0001) and multivariate (OR 0.64, CI 0.59-0.68, p < 0.0001) regressions showed statistically significant reduction of acute gout among hospitalized patients who were current smokers but were assumed to have ceased smoking during hospital stay. Active tobacco use was associated with a lower risk of acute inpatient gouty arthritis, even when controlling for conventional risk factors. More study is needed to correlate this finding with uric acid levels, and a better understanding of the mechanisms that explain this finding are necessary.