Effect of extended-release niacin on plasma lipoprotein(a) levels: A systematic review and meta-analysis of randomized placebo-controlled trials

© 2016 Elsevier Inc.Aim Lipoprotein(a) (Lp(a)) is a proatherogenic and prothrombotic lipoprotein. Our aim was to quantify the extended-release nicotinic acid Lp(a) reducing effect with a meta-analysis of the available randomized clinical trials. Methods A meta-analysis and random-effects meta-regression were performed on data pooled from 14 randomized placebo-controlled clinical trials published between 1998 and 2015, comprising 17 treatment arms, which included 9013 subjects, with 5362 in the niacin arm. Results The impact of ER niacin on plasma Lp(a) concentrations was reported in 17 treatment arms. Meta-analysis suggested a significant reduction of Lp(a) levels following ER niacin treatment (weighted mean difference – WMD: - 22.90%, 95% CI: - 27.32, - 18.48, p <0.001). Results also remained similar when the meta-analysis was repeated with standardized mean difference as summary statistic (WMD: - 0.66, 95% CI: - 0.82, - 0.50, p <0.001). When the studies were categorized according to the administered dose, there was a comparable effect between the subsets of studies with administered doses of <2000 mg/day (WMD: - 21.85%, 95% CI: - 30.61, - 13.10, p <0.001) and = 2000 mg/day (WMD: - 23.21%, 95% CI: - 28.41, - 18.01, p <0.001). The results of the random-effects meta-regression did not suggest any significant association between the changes in plasma concentrations of Lp(a) with dose (slope: - 0.0001; 95% CI: - 0.01, 0.01; p = 0.983), treatment duration (slope: - 0.40; 95% CI: - 0.97, 0.17; p = 0.166), and percentage change in plasma HDL-C concentrations (slope: 0.44; 95% CI: - 0.48, 1.36; p = 0.350). Conclusion In this meta-analysis of randomized placebo-controlled clinical trials, treatment with nicotinic acid was associated with a significant reduction in Lp(a) levels.