Detrusor overactivity (DO) in women can be accompanied by heterogeneous voiding dysfunction. We used pressure–flow study (PFS) data to clarify the prevalence of bladder outlet obstruction (BOO) and detrusor underactivity (DU) and to explore whether voiding patterns differ by DO subtype (phasic vs terminal).

We retrospectively selected female patients from our institutional urodynamic study (UDS) database who showed DO on cystometry (CMG) and had evaluable PFS data. BOO and DU were diagnosed based on the ICS-SUFU female nomogram framework (1). BOO was defined as BOOIf (Pdet@Qmax − 2.2×Qmax) > 18 (Solomon–Greenwell), and DU as PIP1(Pdet@Qmax + Qmax) < 30. Normal voiding was defined using the Bristol criteria: Pdet@Qmax ≥20 cmH₂O, Qmax ≥20 mL/s, and BE% = 100. (2)

Ninety-three women with DO were selected from our UDS database analyzed (mean age 68.4±12.6 years). DO subtypes were Group A (phasic only) n=36, Group B (terminal only) n=25, and Group C (phasic+terminal) n=32. Overall mean UDS parameters were: free uroflowmetry Qmax 13.2±10.6 mL/s, voided volume 157.5±123.6 mL, PVR 91.3±171.8 mL, and BEV% 68.6±31.9%. CMG showed FS 160.8±112.4 mL and MCC 333.0±221.8 mL. PFS showed Qmax 12.3±7.4 mL/s and Pdet@Qmax 31.2±19.6 cmH₂O; BCI was 92.6±38.0 and PIP1 43.5±19.4. Scatter Plot (Qmax vs Pdet@Qmax) demonstrated no clear distribution difference among each group (Figure 1). A nonparametric post hoc multiple comparison revealed a significant difference in PdetQmax between Group A and Group B (Table 1)
The prevalence of DU (by PIP1) was 20.4% (19/93) and that of BOO (by BOOIf) was 29.0% (27/93). Comparing terminal DO absence (Group A) vs present (Groups B+C), BOO occurred in 22% (8/36) vs 36% (21/57), while DU occurred in 36% (13/36) vs 10% (6/57). When comparing patients without terminal DO (Group A) versus those with terminal DO (Groups B+C), BOO was observed in 22% (8/36) vs 36% (21/57), while DU was observed in 36% (13/36) vs 10% (6/57), respectively.

Thus, BOO tended to be more frequent in the terminal DO group, whereas DU tended to be more frequent in the phasic-only group. Across both phasic and terminal DO patterns, a negative relationship was noted: as Pdet@Qmax increased, Qmax tended to decrease. So-called terminal DO voiding recognized in Group B can elevate PdetQmax and may therefore lead to a diagnosis of BOO even in the absence of obvious anatomical bladder outlet obstruction; caution is warranted.

PFS-based analysis demonstrated that women with DO frequently have concomitant voiding dysfunction. Phasic-only DO and terminal DO may show different distributions of BOO and DU, and recognizing these subtype-associated patterns may help in selecting appropriate treatment strategies.

Neurourol Urodyn 2023; 42:1603–1627
European Urology 2016;69:361-369

Continence 19S (2026) 102627
DOI: 10.1016/j.cont.2026.102627