Twelve-month outcomes following midurethral sling procedures for stress incontinence: impact of obesity

Objective: To evaluate impact of body mass index (BMI) ≥30 on objective and subjective cure rates 12 months after midurethral sling surgery.

Design: Secondary analysis.

Setting: Three hospitals in Calgary, Canada, 2005-07.

Population: A total of 182 women enrolled in a randomised control trial of tension-free vaginal tape versus transobturator tape.

Methods: Women were classified as obese or nonobese from height and weight on day of surgery. Women underwent postoperative standardised pad tests, self-reporting of urinary incontinence, and quality of life scores. Categorical data compared with chi-square or Fisher's exact, continuous data compared with Mann-Whitney U test.

Main outcome measures: Primary outcome was objective cure, defined as <1 g urine loss on postoperative 1-hour pad test. Secondary outcomes were subjective cure of incontinence (no stress incontinence in previous 7 days), presence of urinary urgency in previous 7 days, Urogenital Distress Inventory (UDI-6) scores, Incontinence Impact Questionnaire (IIQ-7) scores, and surgical complication rates.

Results: Objective cure differed, with 85.6% of nonobese women leaking <1 g on 1-hour pad test, versus 67.8% of obese women (P = 0.006, risk difference [RD] 17.8%, 95% confidence interval [95% CI] 4.2-31.4%). Subjective cure was 85.8% for nonobese women versus 70.7% for obese women (P = 0.016, RD 15.1%, 95% CI 1.9-28.4%). For both groups, improvement was seen for postoperative UDI-6 (median -33.3 [-44.4 to -22.2] and -27.2 [-44.4 to -16.7]) and IIQ-7 scores (median -26.2 [-45.2 to -14.3] and -23.8 [-42.9 to -14.3]). No differences existed in rates of operative complications between the two groups.

Conclusion: Twelve months after midurethral sling surgery, obese women experience lower rates of cure than those who are nonobese.