Prescribing patterns of allopurinol and febuxostat according to directives on the reimbursement criteria and clinical guidelines: analysis of a primary care database.

According to American clinical guidelines, allopurinol and febuxostat may be prescribed as first-line therapy to treat hyperuricemia. However, the Italian Medicines Agency directive, called Nota 91, allows the reimbursement of second-line febuxostat in the case of failure and/or intolerance of a previous allopurinol therapy, so partially embracing European League Against Rheumatism recommendations and the British Society for Rheumatology Guideline. Such inconsistency might lead to heterogeneity among General Practitioners (GPs) in treatment of hyperuricemia. This study, therefore, aimed to evaluate the prescribing behavior of GPs in terms of compliance with Nota 91 and/or official guidelines. Using the Health Search Database, a retrospective cohort study was conducted to evaluate the patterns of use of allopurinol and febuxostat between 2011 and 2016. In total, 44,257 and 5837 patients were prescribed with allopurinol and febuxostat, respectively. Among febuxostat users, 4321 (74%) had a previous allopurinol treatment; 92% of switches to febuxostat were related to hyperuricemia, whereas 9% of switchers presented intolerance to allopurinol; 26% of patients were prescribed with febuxostat as first-line therapy. The presence of diabetes and/or moderate/severe renal disease were statistically significant determinants of febuxostat use as first-line therapy. Prescriptions of febuxostat were highly compliant to Nota 91. Only a sub-group of frontline prescriptions of febuxostat were mainly driven by the presence of renal dysfunction, which is able to increase the risk of allopurinol intolerance and/or inefficacy. These findings indicate that GPs' prescribing behavior for hyperuricemia is highly compliant with both regulatory directives and clinical guidelines.