Increasing Age Predicts Increasing Residual Urine Volume

To determine reference values for postvoid residual (PVR) volume for patients referred to a tertiary urogynecology center.

After Institutional Review Board approval, we performed a retrospective chart review of all new patients presenting to our referral center. We assessed associations between PVR and patient demographics, pelvic floor symptoms, and physical examination by Wilcoxon rank sum or Kruskal-Wallis tests as appropriate. A multivariable logistic regression model was used to calculate odds ratios for patient characteristics associated with PVR in the top age range-specific decile.

Three hundred sixty-one patients were included in the analysis. The median PVR was 20 mL (interquartile range, 1st, 3rd quartiles, 10, 50). Older age was associated with higher PVR (P < 0.001). The median PVR in participants younger than 40 years was 10 mL, ages 40 to 49 years was 18 mL, 50 to 69 years was 20 mL, 70 to 79 years was 38 mL and in women older than 79 years was 50 mL. A multivariable analysis showed that prolapse stage (odds ratio [OR], 3.46 with prolapse stage 2-4 vs stage 0-1; P = 0.001), history of stroke (OR, 7.62; [95% CI 2.17-26.77, P = 0.002]), narcotic use (OR, 2.45; [95% CI 1.01-5.92; P = 0.047]), and urinary frequency (OR, 2.61; [95% CI, 1.14-5.98; P = 0.024]) were risk factors for increased PVR (as defined at >90%ile for age), independent of the age-related elevation.

The majority of patients presenting for urogynecologic evaluation had a low PVR with a median of 20 mL. Postvoid residual was higher for older age groups but nearly all volumes were less than 100 mL. The utility of a PVR measurement is highest for patients with pelvic organ prolapse, urinary frequency, narcotic use, or history of stroke.