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 24weeks) and allopurinol dose (100-300mg/day), all the studies showed decreases in the mean serum uric acid level (95% confidence interval: -2.61 to -1.55 (4weeks), -2.94 to -1.09 (12weeks) and -2.59 to -1.22 (24weeks); 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 (4weeks) and -7.18 to -0.32 (12weeks); 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.