Can men with lower urinary tract symptoms (LUTs) predict voided volumes?

Purpose To determine if patients can accurately estimate volumes voided in a bladder diary, and to determine the patient characteristics that are most predictive of accuracy in volume estimation in the workup of lower urinary tract symptoms (LUTs). Methods We prospectively collected data on 180 consecutive patients undergoing a workup for LUTs at a tertiary care facility. Data collected include American Urological Association Symptom Scores (AUASS), flow time and rate, and one time measurement of voided volume into a blinded uroflow. Baseline characteristics and demographics were recorded. Descriptive statistics and linear regression analysis were performed to examine predictors of estimated voiding volume (mL) in SAS Version 9.4 (SAS Institute, Inc., Cary, NC, USA). Results Median age and BMI were 64 years (SD = 15.4) and 26.9 kg/m(2) (SD = 4.6), respectively. The median estimated voided volume and actual voided volume were 120 mL (range 1-480) and 101.5 mL (range 6.5-622.0), respectively. On linear regression analysis, 47.1% of patients estimated volume voided with a 20% margin of error, and 63.2% of patients estimated with a 30% margin of error. Each 1-year increase in age correlated with a 2% decrease in the odds of estimating voided volume within 20% of actual volume (p < 0.05). For each 1 unit increase in flow rate, there was an 8% (p < 0.005) increase in the odds of estimating voided volume within 20% of actual volume. Conclusions Just under half of patients can accurately estimate volume voided with a margin of error of 20%.