Effect of allopurinol and uric acid normalization on serum lipids hyperuricemic subjects: A systematic review with meta-analysis

Although uric acid is not part of any definition of metabolic syndrome, a number of studies have shown strong associations between the concentration of uric acid and metabolic syndrome or its components. The purpose of this systematic review with meta-analysis was to evaluate, using prospective interventional studies, the effects of allopurinol therapy and uric acid normalization on serum concentrations of triacylglycerol, total-cholesterol, LDL-cholesterol and HDL-cholesterol in hyperuricemic subjects. A systematic search of the PubMed and Scopus databases was performed following the guidelines described in the PRISMA statement. Seven studies were included in the meta-analysis, including six randomized controlled trials and one controlled before-and-after study. Despite differences in the follow-up periods (4, 12 and 24 weeks) and allopurinol dose (100-300 mg/day), all the studies showed decreases in the mean serum uric acid level (95% confidence interval: − 2.61 to − 1.55 (4 weeks), − 2.94 to − 1.09 (12 weeks) and − 2.59 to − 1.22 (24 weeks); p < 0.05). However, no effect was observed based on differences in mean serum triacylglycerol and total- and LDL-cholesterol concentrations, independent of the follow-up period. Allopurinol therapy during weeks 4 and 12 induced a decrease in the mean HDL-cholesterol level (95% confidence interval: − 7.22 to − 0.47 (4 weeks) and − 7.18 to − 0.32 (12 weeks); p < 0.05). This review suggests that allopurinol and uric acid normalization does not improve serum lipid levels, although larger and longer trials of higher quality are needed to confirm this.