Role of detrusor overactivity and interval between bladder sensations on the severity of overactive bladder symptoms in patients with multiple sclerosis

Purpose: This study aimed to assess the relationship between kinetics of bladder sensations perception, detrusor overactivity (DO), and severity of overactive bladder (OAB) symptoms in patients with multiple sclerosis (PwMS).

Methods: All PwMS who underwent urodynamic assessment including three cystometries (20mL/min, 100mL/min, and 100mL/min with 4°C fluid) between June 2020 and October 2022 were included in this retrospective study. Data collected were bladder diaries, symptoms assessed with Urinary Symptom Profile (USP), bladder sensations with first desire to void (FDV) and strong desire to void (SDV) during the 20mL/min cystometry, and presence of DO. The volume between FDV and SDV was calculated (FDV-SDV).

Results: Two hundred and two patients were included (mean age 47.4±11.8 years, median EDSS 3 IQR [2-5], 74.7% of women). DO was found in 104 (51.5%) patients. Reduced FDV-SDV volume (<50mL) was significantly associated with the occurrence of DO (27% vs. 5%; P<0.0001), and DO was associated with earlier sensations during cystometries (167±88mL vs. 204±109mL for FDV, P=0.02; 285±131mL vs. 353±116mL for SDV, P<0.001). In patients without DO, FDV-SDV volume was correlated with void frequency (rho=-0.30; P=0.03), mean voided volume (rho=0.52; P<0.001), and USP OAB sub-score (rho=0.32; P<0.01), especially with the item related to the warning time (rho=0.38; P<0.01).

Conclusion: DO has an impact on bladder sensations during cystometries in PwMS. In the absence of DO, a reduced FDV-SDV volume may have a significant impact on OAB severity, especially in reducing the warning time.