Post-void residual urine volume is not a good predictor of the need for invasive therapy among patients with benign prostatic hyperplasia

Purpose: We assessed the value of baseline PVR as predictor of the need for invasive therapy during long-term followup of patients with clinical BPH treated initially with α1-blockers or WW. Materials and Methods: The records of a cohort of 942 patients with BPH treated with α₁- blockers or WW were reviewed. Baseline I-PSS scores, PSA, prostate volume, uroflowmetry, pressure flow parameters and followup data were collected prospectively. Correlations between PVR and other baseline parameters were calculated. The 5-year cumulative risks of invasive therapy were calculated with the Kaplan-Meier method. After stratification of PVR by various cutoff levels (50, 100 and 300 ml), rate ratios between large and small PVRs were calculated using proportional hazards analyses. Results: PVR has weak (-0.2<R <0.2) correlations with other baseline parameters. With increasing PVR cutoff levels, the 5-year cumulative risk of invasive therapy for the large PVR subgroup, increases from 45% to 64% and from 15% to 21% in the α1-blockers and WW group, respectively. Large PVR yields a significant 2-fold up to a 4-fold increased risk of invasive therapy compared to small PVR in both treatment groups. In multivariate models these significant risk differences largely disappear, although a statistically not significant higher risk remains for the large PVR (greater than 300 ml) patients. Conclusions: In general, baseline PVR has little prognostic value for the risk of BPH related invasive therapy in patients on α1-blocker and WW. Only patients with large PVR have a 2-fold increased risk of invasive therapy compared to patients with smaller PVR.