Effect of morbid obesity on mid-urethral sling effecacy for the management of stress urinary incontinence.

Objectives: Mid-urethral slings (MUS) are the most widely accepted and studied minimally invasive procedure for the management of stress urinary incontinence (SUI) (1). However, studies have suggested decrease in efficacy of MUS procedures in the obese patients (2). In our urban population, we are encountering an increasing number of morbidly obese patients (BMI≥40) presenting with stress urinary incontinence interested in surgical management. The aim of our study was to assess the success rate of MUS in the morbidly obese patients. Our secondary outcome was to assess difference in complication rates between patients with BMI≥40 and \u3c40. Methods: This is a retrospective chart review. We collected data on all patients that have undergone a sling procedure between 2008-2015 in our health system. Failure was defined as reported SUI symptoms or treatment for SUI. Variables collected were BMI, smoking status, comorbidities, peri-operative complications (within 24hrs), short term (within 30days) and long term complications (\u3e30days) and the follow-up time. Analyses included ANOVA, Chi-square test, logistic, Kaplan Meier method and Cox regression. Results: We identified 565 patients, 130 were eliminated as they underwent a sling procedure other than MUS and for follow-up time \u3c6 months. 435 were included in our analysis, 49 patients were morbidly obese (mean=44.9 +/-5.07), 164 with BMI of 30-39 (mean=33.6 +/-2.63), 123 with BMI of 25-29.9 (mean= 27.4 +/-1.13) and 99 with BMI ≤25 (mean=23 +/-1.68). Our mean follow-up time was 52 months. There was no difference in failure rate between normal weight, overweight and class 1 and 2 obesity groups even after controlling for potential confounders such as diabetes mellitus (DM), smoking status, or chronic obstructive pulmonary disease (COPD) (p=0.18). Morbid obesity (BMI\u3e40) was associated with increased risk of failure when compared to the normal weight category (p=0.04, OR: 2.38, CI:1.05-5.39). COPD independently was associated with an increased risk of failure, odds ratio p=0.05, OR=1.72, CI=0.98-2.95). BMI category was not a significant predictor of peri-operative, short-term post-operative or long-term post-operative complications (p=0.33, p=0.16 and p=0.15 respectively) and also after controlling for other comorbidities as potential confounders. Conclusions: BMI has significant impact on MUS failure in the morbidly obese patients when compared to the normal weight category. This effect was not seen in overweight and Class 1 and 2 obesity categories. COPD independently and after stratification based on BMI category was associated with a higher failure rate and recurrence of stress urinary incontinence