Alpha-blockers after shock wave lithotripsy for renal or ureteral stones in adults

Abstract

BACKGROUND: Shock wave lithotripsy (SWL) is a widely used method to treat renal and ureteral stone. It fragments stones into smaller pieces that are then able to pass spontaneously down the ureter and into the bladder. Alpha-blockers may assist in promoting the passage of stone fragments, but their effectiveness remains uncertain. OBJECTIVES: To assess the effects of alpha-blockers as adjuvant medical expulsive therapy plus usual care compared to placebo and usual care or usual care alone in adults undergoing shock wave lithotripsy for renal or ureteral stones. SEARCH METHODS: We performed a comprehensive literature search of the Cochrane Library, the Cochrane Database of Systematic Reviews, MEDLINE, Embase, several clinical trial registries and grey literature for published and unpublished studies irrespective of language. The date of the most recent search was 27 February 2020. SELECTION CRITERIA: We included randomized controlled trials of adults undergoing SWL. Participants in the intervention group had to have received an alpha-blocker as adjuvant medical expulsive therapy plus usual care. For the comparator group, we considered studies in which participants received placebo. DATA COLLECTION AND ANALYSIS: Two review authors independently selected studies for inclusion/exclusion, and performed data abstraction and risk of bias assessment. We conducted meta-analysis for the identified dichotomous and continuous outcomes using RevManWeb according to Cochrane methods using a random-effects model. We judged the certainty of evidence on a per outcome basis using GRADE. MAIN RESULTS: We included 40 studies with 4793 participants randomized to usual care and an alpha-blocker versus usual care alone. Only four studies were placebo controlled. The mean age of participants was 28.6 to 56.8 years and the mean stone size prior to SWL was 7.1 mm to 13.2 mm. The most widely used alpha-blocker was tamsulosin; others were silodosin, doxazosin, terazosin and alfuzosin. Alpha-blockers may improve clearance of stone fragments after SWL (risk ratio (RR) 1.16, 95% confidence interval (CI) 1.09 to 1.23; I² = 78%; studies = 36; participants = 4084; low certainty evidence). Based on the stone clearance rate of 69.3% observed in the control arm, an alpha-blocker may increase stone clearance to 80.4%. This corresponds to 111 more (62 more to 159 more) participants per 1000 clearing their stone fragments. Alpha-blockers may reduce the need for auxiliary treatments after SWL (RR 0.67, 95% CI 0.45 to 1.00; I² = 16%; studies = 12; participants = 1251; low certainty evidence), but also includes the possibility of no effect. Based on a rate of auxiliary treatments in the usual care arm of 9.7%, alpha-blockers may reduce the rate to 6.5%. This corresponds 32 fewer (53 fewer to 0 fewer) participants per 1000 undergoing auxiliary treatments. Alpha-blockers may reduce major adverse events (RR 0.60, 95% CI 0.46 to 0.80; I² = 0%; studies = 7; participants = 747; low certainty evidence). Major adverse events occurred in 25.8% of participants in the usual care group; alpha-blockers would reduce this to 15.5%. This corresponds to 103 fewer (139 fewer to 52 fewer) major adverse events per 1000 with alpha-blocker treatment. None of the reported major adverse events appeared drug-related; most were emergency room visits or rehospitalizations. Alpha-blockers may reduce stone clearance time in days (mean difference (MD) -3.74, 95% CI -5.25 to -2.23; I² = 86%; studies = 14; participants = 1790; low certainty evidence). We found no evidence for the outcome of quality of life. For those outcomes for which we were able to perform subgroup analyses, we found no evidence of interaction with stone location, stone size or type of alpha-blocker. We were unable to conduct an analysis by lithotripter type. The results were also largely unchanged when the analyses were limited to placebo controlled studies and those in which participants explicitly only received a single SWL session. AUTHORS' CONCLUSIONS: Based on low certainty evidence, adjuvant alpha-blocker therapy following SWL in addition to usual care may result in improved stone clearance, less need for auxiliary treatments, fewer major adverse events and a reduced stone clearance time compared to usual care alone. We did not find evidence for quality of life. The low certainty of evidence means that our confidence in the effect estimate is limited; the true effect may be substantially different from the estimate of the effect.