Effect of niacin on erectile function in men suffering erectile dysfunction and dyslipidemia.

INTRODUCTION Dyslipidemia is closely related to erectile dysfunction (ED). Evidence has shown that the lipid-lowering agent, 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor (statins), can improve erectile function. However, information about the potential role of another class of lipid-lowering agent, niacin, is unknown. AIM To assess the effect of niacin alone on erectile function in patients suffering from both ED and dyslipidemia. METHODS A single center prospective randomized placebo-controlled parallel-group trial was conducted. One hundred sixty male patients with ED and dyslipidemia were randomized in a one-to-one ratio to receive up to 1,500 mg oral niacin daily or placebo for 12 weeks. MAIN OUTCOME MEASURES The primary outcome measure was the improvement in erectile function as assessed by question 3 and question 4 of the International Index of Erectile Function (IIEF Q3 and Q4). Secondary outcome measurements included the total IIEF score, IIEF-erectile function domain, and Sexual Health Inventory for Men (SHIM) score. RESULTS From the overall analysis, the niacin group showed a significant increase in both IIEF-Q3 scores (0.53 ± 1.18, P < 0.001) and IIEF-Q4 scores (0.35 ± 1.17, P = 0.013) compared with baseline values. The placebo group also showed a significant increase in IIEF-Q3 scores (0.30 ± 1.16, P = 0.040) but not IIEF-Q4 scores (0.24 ± 1.13, P = 0.084). However, when patients were stratified according to the baseline severity of ED, the patients with moderate and severe ED who received niacin showed a significant improvement in IIEF-Q3 scores (0.56 ± 0.96 [P = 0.037] and 1.03 ± 1.20 [P < 0.001], respectively) and IIEF-Q4 scores (0.56 ± 1.03 [P = 0.048] and 0.84 ± 1.05 [P < 0.001], respectively] compared with baseline values, but not for the placebo group. The improvement in IIEF-EF domain score for severe and moderate ED patients in the niacin group were 5.28 ± 5.94 (P < 0.001) and 3.31 ± 4.54 (P = 0.014) and in the placebo group were 2.65 ± 5.63 (P < 0.041) and 2.74 ± 5.59 (P = 0.027), respectively. There was no significant improvement in erectile function for patients with mild and mild-to-moderate ED for both groups. For patients not receiving statins treatment, there was a significant improvement in IIEF-Q3 scores (0.47 ± 1.16 [P = 0.004]) for the niacin group, but not for the placebo group. CONCLUSIONS Niacin alone can improve the erectile function in patients suffering from moderate to severe ED and dyslipidemia.