To assess strenght, duration and main characteristics of detrusor contraction (DC) in detrusor underactivity (DUA) women.

This was a comparative prospective study (2021-2022) on DC characteristics in females with DUA (DUA-G) compared with those of women without DUA (Control Group- CG) underwent urodynamics (UD)  for LUTD. DUA was defined when at least one of the following UD criteria was met: 1) Jeong; 2) Abarbanel and Marcus; 3) BVE criteria; 4) PIP1. Statistical analisis tests were: T-Test, Youden, AUC and sensibility/specificity calculation.

Data were completed on 206 women: 104 DUA (50.5%), 102 CG (49.5%). Data on main DC charachteristics of the 2 groups are reported in the table. Median DC duration was 61.5 sec in DUA-G and 73 sec in CG, median voiding duration 50 sec in DUA-G and 38 sec in CG. Median Pdet/Qmax was 12.5 cmH2O in DUA-G and 20 cmH20 in CG. Thresholds of Ratio DC duration/voiding time <1.375, Pdet/Qmax < 14 cmH2O, Qmax < 14ml/s had the higher AUC and good both sensibility and specificity. Combining these parameters, in CG 49% had none of the markers below these cut-off, 41.2% with at least 1, 8.8% 2, 0.9% 3. In DUA-G the rate of women with none parameter with lower cut-off was 3.9%, at least 1 31.4%, 2 48%, all 18.6%. DC duration lower than 45 sec showed the higher specificity for DUA (90%) but with a very low sensibility (28%).

As expected and according to ICS definition, duration (1 min) and strenght (12 cmH20) of DC were significantly reduced in DUA-G, with prolonged voiding time and larger post-void residual of urine. In the average, DUA DC lasted 10 sec less than normal DC, and was 9 cmH20 weaker than in no DUA DC. Ratio DC duration/voiding time, Pdet/Qmax, Qmax were the parameters most related to DUA and we found tresholds with high AUC and good sensibility and specificty. Interestingly, the majority of women with normal DC showed none or at least 1 of these parameters under reported cut-off (91%), while only 9% had concomitancy of 2 or 3 markers below thresholds. In DUA-G 66% of the women had 2 or 3 concurrent parameters with lower thresholds. Therefore, the coexisting occurrence of 2 or 3 of these parameters with lower cut- off could be a warning for detrusor impairment.

Our study defined how the duration and strength of the DUA DC were reduced compared to normal DC also reporting parameters that could be red flags for detrusor impairment.