Cardiovascular Risk and Mortality in Patients with Hyperuricemia Treated with Febuxostat or Allopurinol: a Retrospective Nation-wide Cohort Study in Austria 2014-2017

Patients with hyperuricemia and gout are at an increased risk for cardiovascular (CV) disease. Inhibition of the xanthine oxidase with allopurinol or febuxostat have become the mainstay for urate lowering therapy. However, it has been suggested that febuxostat increases the risk for CV mortality as compared to allopurinol. The aim of this retrospective cohort study was to assess the CV risk among patients with febuxostat or allopurinol therapy. Patients who initiated urate lowering therapy with febuxostat or allopurinol between 2014 and 2017 were selected from the drug reimbursement database of the Austrian health insurances funds. The primary CV endpoint was a composite of angina pectoris, nonfatal myocardial infarction, nonfatal subarachnoid or cerebral hemorrhage, nonfatal ischemic stroke, or death from any cause. In total, 28.068 patients (62.1% male) with a mean age of 71 years were included. 7.767 initiated febuxostat treatment and 20.301 received allopurinol. The incidence rate per 100 patient-years of the composite primary endpoint was 448 (febuxostat) and 356 (allopurinol) with a corresponding adjusted hazard ratio (HR) of 0.58 (95% CI 0.53-0.63) for allopurinol vs. febuxostat initiators. Similar HR were found for secondary endpoints including all-cause mortality [0.61 (95% CI 0.55-0.68)] and separate analyses of cardiac events [0.48 (95% CI 0.38-0.61)] and ischemic stroke [0.47 (95% CI 0.36-0.61)]. Data from this Austrian population-based study suggests that febuxostat initiators are at an increased risk for nonfatal CV events or death from any cause as compared to those with allopurinol. This is consistent with CV concerns of other trials, which limited the broad therapeutic use of febuxostat.