Obesity as an independent risk factor for poor long-term outcome after mid-urethral sling surgery

Introduction: High body mass index (BMI) is a risk-factor for stress urinary incontinence (SUI). Mid-urethral sling (MUS) surgery is an effective treatment of SUI. The aim of this study was to investigate if there is an association between BMI at time of MUS-surgery and the long-term outcome at 10 years. Material and Methods: Women who went through MUS surgery in Sweden between 2006 and 2010 and had been registered in the Swedish National Quality Register of Gynecological Surgery were invited to participate in the 10-year follow-up. A questionnaire was sent out asking if they were currently suffering from SUI or not and their rated satisfaction, as well as current BMI. SUI at 10 years was correlated to BMI at the time of surgery. SUI at 1 year was assessed by the postoperative questionnaire sent out by the registry. The primary aim of the study was to investigate if there is an association between BMI at surgery and the long-term outcome, subjective SUI at 10 years after MUS surgery. Our secondary aims were to assess whether BMI at surgery is associated with subjective SUI at 1-year follow-up and satisfaction at 10-year follow-up. Results: The subjective cure rate after 10 years was reported by 2108 out of 2157 women. Higher BMI at the time of surgery turned out to be a risk factor for SUI at long-term follow-up. Women with BMI <25 reported subjective SUI in 30%, those with BMI 25-<30 in 40%, those with BMI 30-<35 in 47% and those with BMI >= 35 in 59% (p < 0.001). Furthermore, subjective SUI at 1 year was reported higher by women with BMI >= 30, than among women with BMI <30 (33% vs. 20%, p < 0.001). Satisfaction at 10-year follow-up was 82% among women with BMI <30 versus 63% if BMI >= 30 (p < 0.001). Conclusions: We found that higher BMI at the time of MUS surgery is a risk factor for short- and long-term failure compared to normal BMI.