Predictors of sling revision after mid-urethral sling procedures: a case–control study AA Clancy, a I Gauthier, a FD Ramirez, b,c D Hickling, d,e D Pascali a a Division of Urogynecology, Department of Obstetrics and Gynecology, University of Ottawa, Ottawa, ON, Canada b School of Epidemiology and Public Health, University of Ottawa, Ottawa, ON, Canada c Division of Cardiology, University of Ottawa Heart Institute, Ottawa, ON, Canada d Division of Urology, Department of Surgery, University of Ottawa, Ottawa, ON, Canada e The Ottawa Hospital Research Institute, Ottawa, ON, Canada Correspondence: AA Clancy, Division of Urogynecology, Department of Obstetrics and Gynecology, The Ottawa Hospital, 501 Smyth Road, Ottawa, ON K1H 8L6, Canada. Email: aclancy@toh.ca Accepted 29 August 2018. Published Online 24 October 2018. Objective To identify patient characteristics and surgical factors predictive of complications requiring mid-urethral sling (MUS) revision/removal. Design Case–control study. Setting Tertiary academic centre in Canada. Population One hundred and seven women undergoing MUS revision/removal between 2005 and 2016 were matched with 214 controls by date of index MUS procedure (2:1 ratio). Methods Data on patient and surgical factors were obtained via manual electronic and paper chart review. Three sets of pre- specified simple and multivariable logistic regression models were fitted to: (1) examine previously reported risk factors for MUS revision after primary surgical treatment; (2) identify preoperative predictors of MUS complications requiring revision/removal; and (3) identify surgical factors associated with this outcome after adjusting for potential confounding factors. Main outcome measures Crude and adjusted odds ratios (ORs) with 95% confidence intervals (95% CIs) for patient and surgical factors. Results The median time to MUS revision was 153 days (interquartile range, IQR 49–432 days). Active smoking status (OR 2.29, 95% CI 1.13–4.63, P = 0.03), having had a previous hysterectomy (OR 3.88, 95% CI 2.02–7.46, P < 0.01), and undergoing concomitant pelvic organ prolapse surgery at the time of the index MUS procedure (OR 2.63, 95% CI 1.32–5.52, P < 0.01) were independently associated with the need for MUS revision/removal. Sling type (obturator versus retropubic), method of tensioning (to cough versus over instrument), anaesthetic type, and estimated blood loss were not associated with this outcome in the analysis presented here. Conclusions Active smoking status, having had a previous hysterectomy, and undergoing concomitant surgery for pelvic organ prolapse are risk factors for requiring subsequent MUS revision/removal. Keywords Mesh complications, sling revision, suburethral sling, urinary incontinence. Tweetable abstract Risk factors for sling revision include smoking, previous hysterectomy, and concomitant prolapse surgery. Linked article This article is commented on by H Hesham, p. 426 in this issue. To view this mini commentary visit https://doi.org/10.1111/1471-0528.15533. Please cite this paper as: Clancy AA, Gauthier I, Ramirez FD, Hickling D, Pascali D. Predictors of sling revision after mid-urethral sling procedures: a case–control study. BJOG 2019;126:419–426. Introduction Mid-urethral sling (MUS) procedures are the most com- monly performed surgical treatment worldwide for female stress urinary incontinence because of their minimally inva- sive nature, short surgical time, and low complication rates. 1 Success rates for MUS are estimated to be 80–90% with excellent long-term durability; however, a small pro- portion of patients subsequently require reoperation for complications such as mesh erosion, mesh exposure, de novo urinary urgency and urge incontinence, recurrent urinary tract infections (UTIs), nerve injury, chronic pain, and most commonly voiding dysfunction/urinary reten- tion. 2–5 Database studies have found that 3–4% of women undergoing mesh procedures for stress urinary inconti- nence require mesh revision (or removal) within 10 years of the index surgery, 6,7 and a recent systematic review of patients undergoing MUS implantation similarly found that 2.3% experience urinary retention requiring surgical revision. 8 419 ª 2018 Royal College of Obstetricians and Gynaecologists DOI: 10.1111/1471-0528.15470 www.bjog.org Urogynaecology