Xanthine oxidase inhibition for the treatment of cardiovascular disease: an updated systematic review and meta-analysis

Background: Previous studies have shown that xanthine oxidase inhibitors (XOI) might improve outcome for patients with cardiovascular disease. However, more evidence is required. Methods and results: We published a meta‐analysis of trials conducted before 2014 examining the effects of XOI on mortality in patients with cardiovascular disease. At least two further trials (N = 323 patients) have since been published. Accordingly, we repeated our analysis after a further search for randomized controlled trials of XOI in PubMed/MEDLINE, EMBASE, and Cochrane Databases. We identified eight relevant trials with 1031 patients. The average age of the patients was 61 years and 68% were men (one study did not report gender). There were 57 deaths in these eight trials, 26 in those assigned to XOI, and 31 in those assigned to the control. The updated meta‐analysis could not confirm a reduction in mortality for patients assigned to XOI compared with placebo (odds ratio 0.84) but 95% confidence intervals were wide (0.48–1.47). Conclusions: This updated meta‐analysis does not suggest that XOI exert a large reduction in mortality but also cannot exclude the possibility of substantial harm or benefit.