Guideline adherence of xanthine oxidase inhibitor utilization to treat gout in primary care.

Background: Gouty arthritis affects 3.9% of American adults and can be effectively managed using urate-lowering therapy initiated at a low dose and titrated to achieve a serum urate of less than 6 mg/dL, the "treat-to-target" approach. This approach is often underused in primary care (PC) settings.

Objective: To identify the proportion of patients newly prescribed a xanthine oxidase inhibitor (XOI) who have their dose titrated to achieve a serum urate (SU) of less than 6 mg/dL.

Methods: This retrospective cohort analysis used prescription orders from administrative electronic health record (EHR) databases to identify adult patients with a diagnosis of gout who were newly prescribed an XOI inhibitor by a CU Medicine PC provider. The primary endpoint was the proportion of patients prescribed an XOI who had their dose up-titrated, achieved a target SU of less than 6 mg/dL, or experienced both of these within 6 months of their first XOI prescription date. Additionally, the number of incident gout flares within 12 months was compared between groups stratified by XOI up-titration performed and achievement of SU target, adjusting for confounders using logistic regression.

Results: Of 1,600 patients evaluated, 851 met eligibility criteria. Of these, 704 (83%) were male, 649 (76%) were White, and the average age was 59 years. Within 6 months, 179 patients (21%) had their XOI dose up-titrated and 239 (28%) achieved an SU of less than 6 mg/dL; 66 patients (8%) had their XOI dose up-titrated and achieved an SU of less than 6 mg/dL within 6 months. 113 patients experienced gout flare, with SU less than 6 mg/dL associated with lower odds of flare (OR = 0.41, 0.23-0.71).

Conclusions: Within a university-based PC population, the proportion of patients newly prescribed an XOI receiving up-titration or achieving SU less than 6 mg/dL within 6 months of medication initiation is low, suggesting that a treat-to-target approach is underused.