Since patients with CKD are at increased risk for gout and alkalinization solubilizes uric acid, investigators sought to determine if baseline bicarbonate or change in bicarbonate was an independent predictor of incident gout in patients with CKD stages 3-5. They queried Optum’s de-identified Integrated Claims-Clinical dataset of US patients (2007-2019) to identify patients with non-dialysis CKD stages 3-5 with two consecutive serum bicarbonate values of 12 to less than 30 mEq/L, 28-365 days apart, with data on 1 or more years prior and 2 or more years of post-index or death within 2 years. Patients without pre-existing gout were followed for up to 11.5 years for diagnosed incident gout. Cox proportional hazards models were used to examine predictors of incident gout, controlling for demographic characteristics, BMI, time-dependent change in serum bicarbonate, and baseline covariates eGFR, serum bicarbonate, hypertriglyceridemia, hypercholesterolemia, hyperuricemia, high C-reactive protein, hypertension, diabetes, obstructive sleep apnea, irritable bowel syndrome, inflammatory bowel disease, Charlson Comorbidity Index score, and prescriptions for thiazide diuretics or metoprolol. Death was similarly evaluated as a competing risk. Among 136,067 patients, 92% had no evidence of gout during the pre-index period. During 11.5-years of follow-up (median 4.2 years), male sex, Black or Asian race, and hyperuricemia were most strongly associated with incident gout among covariates. Hispanic ethnicity, low-income status, higher baseline eGFR, and lower overall comorbidity burden were associated with a lower risk of gout. Baseline serum bicarbonate and time-dependent change in serum bicarbonate were not associated with incident gout.
