Risk Factors of Infectious Complications after Ureteroscopy: A Systematic Review and Meta-Analysis Based on Adjusted Effect Estimate

Background: Multiple studies have reported that gender, pre-operative stent insertion, positive pre-operative urine culture results, and diabetes mellitus are associated with infectious complication after ureteroscopy. A previous meta-analysis focused on this topic is based, however, on crude estimate. Further analysis based on adjusted estimates is needed. Methods: PubMed, Web of Science, Embase, and the Cochrane Library database were searched with ureteroscopy, ureteroscopies, ureteroscopic surgical procedures, ureteroscopic surgery, ureteroscopic lithotripsy, flexible ureteroscopic lithotripsy, ureteroscopy (URS), flexible ureterorenoscopy, risk factor, predictor, predicting model, and nomogram until December 15, 2019. The quality of research was evaluated by Newcastle-Ottawa Scale system. Odds ratio (OR) and 95% confidence intervals (CI) of each risk factor were extracted. Meta-analysis was performed with Stata 15.0 software. Heterogeneity was assessed by I². Publication bias was tested by the Egger test, and funnel plot. Meta-regressions and subgroup analysis were further performed. Results: There were 16 studies; 12,357 patients finally were included in this meta-analysis. The association between gender (OR = 1.82, 95% CI: 1.48-2.23, I² = 0%, p = 0.701), pre-operative ureteric stent insertion (OR = 1.91, 95% CI: 1.26-2.91, I² = 40.4%, p = 0.109), diabetes mellitus (OR: 1.40, 95% CI: 1.07-1.85, I² = 34.1%, p = 0.168), positive urine culture before URS (OR: 2.18, 95% CI: 1.34-3.57, I² = 47.2%, p = 0.092), operation duration (OR: 1.03, 95% CI: 1.01-1.04, I² = 70.6%, p = 0.001) and infectious complications was positively significant. All four pooled results were different from results of meta-analysis based on crude estimate. Conclusion: Female gender, pre-operative ureteric stent insertion, diabetes mellitus, positive urine culture results before URS, and operation duration are risk factors for infectious complications after URS. Meta-analysis based on adjusted estimates may be more convincing.