We aimed to search whether the maximum urethral closure pressure (MUCP) can be used to predict outcomes of surgical treatment of stress urinary incontinence.

Search strategy: PubMed and EMBASE were searched for the last time on July, 2015 using the search terms ‘‘maximum urethral closure pressure’’, “MUCP”, ‘‘stress urinary incontinence’’, ‘‘SUI’’, “treatment”. The conference abstracts and some other content-independent articles were not included in this systematic review. We combined the search results and removed duplicate articles in order to obtain an initial set of potentially eligible studies.
Study inclusion/exclusion criteria: Studies were considered eligible if they met all the following inclusion criteria: (i) The articles selected the SUI women patients as sample. (ii) about MUCP was in the articles. (iii) The treatment of the SUI patients was surgical treatment, not drug therapy or material testing. In addition to this, some articles which had the objective to investigate the choice of SUI operation were included as long as they had data statistics about MUCP.
Data extraction: Articles after removing duplicate were assessed independently by two authors (TW, XZ) for possible inclusion. They also extracted data on first author, publication year, patient sources, study design, study size, ethnicity of study population, mean age of patients, follow-up years, patient number of lost to follow-up, surgery type, whether to receive preoperative clinical and urodynamic evaluation, and other clinical characteristics. However, people had disagreement to define the appropriate boundary values of preoperative MUCP. And their studies had used different evaluation criteria for MUCP. Consequently, different articles had different boundary values. We read these articles and summarized 3 main boundary values which were accepted by most people and divided them to 3 subgroups, MUCP threshold value = 20 cmH20 group, MUCP threshold value = 30 cmH20 group and MUCP threshold value = 40 cmH20 group. And also, the numbers of patients before surgery and the surgical outcome of each group were extracted. The surgical outcome represented the patients who were cured by the surgery and had no SUI.
Statistical methods: All calculations and data manipulations were performed using RevMan 5.3 (Cochrane Collaboration, Oxford, UK). Survival data were log-transformed and pooled results were expressed in terms of the log (OR) and standard error of the log (OR). According to the preoperative MUCP boundary values, the articles were divided into 3 subgroups, respectively. We compared the numbers of patients before surgery and the surgical outcome of each subgroup. Forrest plots were used to Meta-analyze the relationship between different preoperative MUCP threshold values and surgical outcome of SUI patients. Heterogeneity was defined as p<0.10 or I2>50%. When homogeneity was adequate (p0.10 or I2≤50%), data were meta-analyzed using a fixed-effects model . Otherwise, data were meta-analyzed using a random-effects model. A pooled OR<1 indicated better surgical outcome for patients with lower boundary values of preoperative MUCP, and it was considered statistically significant if the corresponding 95%CI did not include one.
The Begg's test was performed and funnel plots were generated in STATA 13.0 (STATA Corp., College Station, USA) to assess the potential publication bias; p>0.05 was interpreted to indicate the absence of significant publication bias .

The meta-analysis has included 7 articles which 4 were prospective studies and 3 retrospective studies. The fixed-effect model OR was 0.41 (95% CI 0.28-0.58; P＜001), suggesting that MUCP < than the boundary value is statistically superior to MUCP> boundary value for predicting the outcomes of  surgical treating SUI despite different subgroup of boundary threshold.

All studies in our study that is used composite cure as an outcome demonstrated effects favoring high preoperative UDS values as predictive of SUI after surgery. Our study aimed to know the relationship between preoperative urodynamics study parameters and the outcomes of patients with surgical treatment and want to find an appropriate threshold UDS values between them. Some now presented studies only find the relationship between them, but not intended to propose an appropriate threshold DUS value for predicting SUI patients with surgical treatment.
The strength of this review lies in the systematic methodology used to evaluate the literature. Criteria for inclusion in the review were determined prior to study selection. This systematic review condensed the various findings of dedicated researchers and shed light upon the variation and inconsistencies that persist in the literature.
By our systematic review study, we were intended an appropriate MUCP  threshold value group(MUCP=20 cmh20 MUCP=30cmH20 MUCP=40cmH20) for predicting the SUI patients with surgical treatment ,we can find that The fixed-effect model OR was 0.41 (95% CI 0.28-0.58; P＜001), suggesting that MUCP < than the boundary value is statistically superior to MUCP> boundary value for predicting the outcomes of  surgical treating SUI despite different subgroup of boundary threshold.
So we may use urodynamic study before SUI patients surgical treatment to predict the risk rate of persistent postoperative stress incontinence after surgical treatment, as our findings, if the patients with the MUCP threshold value=30cmH20,it may predict the low risk rate after surgical treatment.
Limitations of our review are that a significant heterogeneity despite we performed the subgroup analysis, the quantity index of the literature database is also too small, and the quantity of surgical way is also not wide enough. The summarize data abstracted from a variety studies, ut most of them may do not have the UDS parameters or did not consider our objective in their research aims, so by our study exclusion criteria we may excluded some good studies.

This meta-analysis of available evidence suggests that preoperative MUCP elevated outcome can predict better outcome in patients with SUI, and the MUCP threshold values are 30cmH20. These findings should be confirmed in more adequately designed, prospective or retrospective studies.