Silodosin for the treatment of lower urinary tract symptoms in men with benign prostatic hyperplasia

Background A variety of alpha-blockers are used for treating lower urinary tract symptoms (LUTS) in men with benign prostatic hyperplasia (BPH). Silodosin is a novel, more selective alpha-blocker, which is specific to the lower urinary tract and may have fewer side effects than other alpha-blockers. Objectives To assess the effects of silodosin for the treatment of LUTS in men with BPH. Search methods We performed a comprehensive search using multiple databases (Cochrane Library, MEDLINE, EMBASE, Scopus, Google Scholar, and Web of Science), trials registries, other sources of grey literature, and conference proceedings with no restrictions on the language of publication or publication status up until 13 June 2017. Selection criteria We included all parallel, randomized controlled trials. We also included cross-over designs. Data collection and analysis Two review authors independently classified studies and abstracted data from the included studies. We performed statistical analyses using a random-effects model and interpreted them according to the Cochrane Handbook for Systematic Reviews of Interventions. We rated the quality of evidence according to the GRADE approach. Main results We included 19 unique studies with 4295 randomized participants across four comparisons for short-term follow-up. The mean age, prostate volume, and International Prostate Symptom Score were 66.5 years, 38.2 mL, and 19.1, respectively. Silodosin versus placebo Based on four studies with a total of 1968 randomized participants, silodosin may reduce urologic symptom scores in an appreciable number of men (mean difference (MD) -2.65, 95% confidence interval (CI) -3.23 to -2.08; low-quality evidence). Silodosin likely does not result in a clinically important reduction in quality of life (MD -0.42, 95% CI -0.71 to -0.13; moderate-quality evidence). It may not increase rates of treatment withdrawal for any reason (relative risk (RR) 1.08, 95% CI 0.70 to 1.66; low-quality evidence). We are uncertain about the effect of silodosin on cardiovascular adverse events (RR 1.28, 95% CI 0.67 to 2.45; very low-quality evidence). Silodosin likely increases sexual adverse events (RR 26.07, 95% CI 12.36 to 54.97; moderate-quality evidence); this would result in 180 more sexual adverse events per 1000 men (95% CI 82 more to 388 more). Silodosin versus tamsulosin Based on 13 studies with a total of 2129 randomized participants, silodosin may result in little to no difference in urologic symptom scores (MD -0.04, 95% CI -1.31 to 1.24; low-quality evidence) and quality of life (MD -0.15, 95% CI -0.53 to 0.22; low-quality evidence). We are uncertain about treatment withdrawals for any reason (RR 1.02, 95% CI 0.62 to 1.69; very low-quality evidence). Silodosin may result in little to no difference in cardiovascular adverse events (RR 0.77, 95% CI 0.53 to 1.12; low-quality evidence). Silodosin likely increases sexual adverse events (RR 6.05, 95% CI 3.55 to 10.31; moderate-quality evidence); this would result in 141 more sexual adverse events per 1000 men (95% CI 71 more to 261 more). Silodosin versus naftopidil Based on five studies with a total of 763 randomized participants, silodosin may result in little to no differences in urologic symptom scores (MD -0.85, 95% CI -2.57 to 0.87; low-quality evidence), quality of life (MD -0.17, 95% CI -0.60 to 0.27; low-quality evidence), treatment withdrawal for any reason (RR 1.25, 95% CI 0.81 to 1.93; low-quality evidence), and cardiovascular adverse events (RR 1.02, 95% CI 0.41 to 2.56; low-quality evidence). Silodosin likely increases sexual adverse events (RR 5.93, 95% CI 2.16 to 16.29; moderate-quality evidence); this would result in 74 more sexual adverse events per 1000 men (95% CI 17 more to 231 more). Silodosin versus alfuzosin Based on two studies with a total of 155 randomized participants, silodosin may or may not result in a clinically important increase in urologic symptom scores (MD 3.83, 95% CI 0.12 to 7.54; low-quality evidence). Silodosin likely results in little to no difference in quality of life (MD 0.14, 95% CI -0.46 to 0.74; moderate-quality evidence). We found no event of treatment withdrawal for any reason. Silodosin may not reduce cardiovascular adverse events (RR 0.67, 95% CI 0.36 to 1.24; low-quality evidence) but likely increases sexual adverse events (RR 37.21, 95% CI 5.32 to 260.07; moderate-quality evidence); this would result in 217 more sexual adverse events per 1000 men (95% CI 26 more to 1000 more). Authors' conclusions Silodosin may reduce urologic symptom scores in an appreciable number of men compared to placebo. Quality of life and treatment withdrawals for any reason appears similar. Its efficacy appears similar to that of other alpha blockers (tamsulosin, naftopidil and alfuzosin) but the rate of sexual side effects is likely higher. Our certainty in the estimates of effect was lowered due to study limitations, inconsistency and imprecision.