A randomized clinical trial comparing intradetrusor onabotulinumtoxinA injection with midurethral sling surgery found no significant difference in symptom improvement at 6 months among females with mixed urinary incontinence who previously failed conservative treatments.
The MUSA (Treatment for Mixed Urinary Incontinence: Midurethral Sling vs Botox A) trial included 137 females with moderate to severe mixed urinary incontinence (MUI) who demonstrated improvement with both treatments. The study findings challenge the historical approach of treating the urgency component first.
"Both groups demonstrated mean improvement in the UDI total score at 6 months with no significant difference between groups," reported lead author Heidi S. Harvie, MD, of the University of Pennsylvania, and colleagues.
The primary outcome measure was change in mixed incontinence symptoms at 6 months using the UDI total score. The onabotulinumtoxinA group showed a mean improvement of −66.8 points (95% confidence interval [CI] = −84.9 to −48.8) compared with −84.9 points (95% CI = −100.5 to −69.3) in the sling group, with a mean difference of 18.1 points (95% CI = −4.6 to 40.7).
While both treatments improved overall MUI symptoms, the sling group demonstrated greater improvement specifically in stress incontinence symptoms: UDI stress score improved by −45.2 points (95% CI = −53.7 to −36.8) compared with −25.1 points (95% CI = −34.1 to −16.1) in the onabotulinumtoxinA group. However, no significant difference was observed in UDI irritative scores between groups.
By 12 months, some participants sought additional treatments. In the sling group, 30.3% received onabotulinumtoxinA, while 15.5% in the onabotulinumtoxinA group underwent sling placement. Additionally, 12.7% of onabotulinumtoxinA recipients received a second injection by 6 months. This percentage increased to 28.2% by 12 months.
The multicenter trial, which was conducted at 7 U.S. sites between July 2020 and September 2022, included females aged 21 years or older who reported moderate or severe bother from both stress urinary incontinence (SUI) and urgency urinary incontinence (UUI) for at least 3 months. They demonstrated a positive cough stress test, documented at least 4 UUI episodes on a 3-day bladder diary, and had unsuccessful conservative treatments and oral medications.
MUI affects an estimated 30% of females 60 years and older in the U.S. The condition "can be profound, encompassing emotional, physical, economic, and social dimensions," the researchers noted.
The study population had a mean age of 59 years and primarily consisted of White women (79.6%). Based on UUI and SUI bother questions from the UDI, 82.5% had MUI that was balanced between stress and urgency components. The mean daily total for incontinence episodes was 7.2, and baseline UDI total mean score was 184.3, which indicated significant symptom severity.
The sling group experienced more recurrent urinary tract infections (17.6% vs 6.9% in the onabotulinumtoxinA group). In the sling group, 2.9% of participants experienced vaginal mesh exposure and 1.5% required sling surgical revision. No patients in the onabotulinumtoxinA group required immediate catheter use, although 2.8% needed intermittent self-catheterization 2 weeks after the procedure.
"Worsening UUI from baseline at any time occurred in 20.8% and 16.2% of the onabotulinumtoxinA and sling groups, respectively," the study authors added.
"These findings may help inform treatment decisions based on patient preference in partnership with clinician recommendations," they noted.
Study limitations included unmasked participants and surgeons, and the possibility that participants anticipated receiving both treatments, which potentially contributed to crossover rates.
Disclosures can be found in the study.
Source: JAMA