Mortality in patients with gout treated with allopurinol: a systematic review and meta-analysis.

BACKGROUND: Urate-lowering therapy (predominantly allopurinol) is highly effective as a treatment for gout, but its wider long-term effects remain unclear. This systematic review and meta-analysis aimed to ascertain the association between allopurinol use in patients with gout and mortality. METHOD: MEDLINE, EMBASE, CINAHL and the Cochrane Library were searched from inception to August 2018. Articles eligible for inclusion used a cohort design and examined cardiovascular or all-cause mortality in patients diagnosed with gout and prescribed allopurinol. Information on study characteristics, design, sample size and mortality risk estimates were extracted. Article quality was assessed using the Newcastle-Ottawa Scale. Included articles were described in a narrative synthesis and (where possible) risk estimate data were pooled. RESULTS: Four articles reported a hazard ratio (HR) risk estimate for all-cause mortality in patients with gout using allopurinol, two of these also reported cardiovascular mortality. Two articles found allopurinol to be protective in patients with gout, one found no statistically significant association and one found no statistically significant effect of escalation of allopurinol dosage on all-cause or cardiovascular-related mortality. Data pooling was possible for all-cause mortality and found no association between allopurinol use in patients with gout and all-cause mortality compared to patients with gout not using allopurinol (adjusted HR 0.80 (95%CI (0.60, 1.05). CONCLUSIONS: There was no significant association between all-cause mortality and allopurinol use in people with gout. However, the number of included studies was small, suggesting that further studies are needed.