Allopurinol Administration for the Prevention of Contrast-Induced Nephropathy: A Network Meta-analysis With Trial Sequential Analysis

Contrast-induced nephropathy represents a major source of morbidity in patients undergoing coronary angiography. Various preventive measures have been proposed, although the optimal one remains still unknown. The aim of the present meta-analysis is to accumulate current literature knowledge and evaluate the renoprotective effects of allopurinol administration before contrast medium exposure. To achieve this, MEDLINE, Scopus, Cochrane Central Register of Controlled Trials, Clinicaltrials.gov, and Google Scholar databases were searched from inception to November 8, 2018. Statistical meta-analysis was conducted with Review Manager 5.3, TSA 0.9.5.5 and R-3.4.3. Six studies were included with a total of 918 patients. Quantitative synthesis revealed that allopurinol leads to significantly reduced incidence of contrast-induced nephropathy compared with hydration alone [odds ratio0.29, 95% confidence interval(0.09–0.90)]. Trial sequential analysis suggested that Z-curve crossed the OʼBrien–Fleming significance boundaries, although required information size was not reached. Network meta-analysis indicated that allopurinol had the highest probability (81.2%) to rank as the most effective intervention compared with hydration and N-acetyl cysteine; however, significant overlap with the rest treatments was noted. In conclusion, the present meta-analysis suggests that allopurinol may represent a promising measure for the prevention of acute kidney injury after coronary angiography. Future large-scale randomized controlled trials should verify this finding, while combinations of allopurinol with other novel interventions should be evaluated to define the most effective strategy to be implemented in the clinical setting.