Electric nerve stimulation for overactive bladder: an umbrella review

Numerous systematic reviews and meta-analyses have reported the effect of electrical nerve stimulation (ENS) on overactive bladder (OAB). However, these results are contradictory. We conducted an umbrella review to summarize the evidence and evaluate the effectiveness of ENS for OAB by using an umbrella review methodology from multiple perspectives with sufficient methodological quality. We searched the PubMed, EMBASE, Cochrane Library, Web of Science, CINAHL and PsycINFO databases and two Chinese databases (CNKI and CBM) to identify articles written in English or Chinese that were published up to 15 February 2021. Two authors of this review independently selected the studies, assessed their quality, and extracted the data from all the included studies. We performed a quality assessment of eligible reviews using the AMSTAR 2.0 tool and estimated the summary effect size, 95% confidence intervals, 95% prediction intervals and heterogeneity. Ten systematic reviews and meta-analyses covering 89 randomized controlled trials and 16 prospective cohort studies with a total population of 5004 participants that investigated the effect of ENS for OAB in terms of 17 different outcomes were identified. ENS seems effective and safety for OAB, with our results showing weak evidence of clinical efficacy and no evidence of side effects. To recommend ENS as a practical treatment option for OAB, however, more high-quality research is needed.