Reliability of Uroflowmetry Pattern Interpretation in Adult Women

Introduction: Uroflowmetry is often used to assess lower urinary tract symptoms (LUTS). Criteria for characterization of flow patterns are not well established, and subjective interpretation is the most common approach for flow curve classification. We assessed the reliability of uroflowmetry curve interpretation in adult women.

Materials and methods: Uroflowmetry studies were obtained in 296 women who participated in an observational cohort study. Four investigators with expertise in female LUTS and urodynamics reviewed and categorized each tracing for interrater reliability. A random subset of 50 tracings was re-reviewed by each investigator for intrarater reliability. The uroflowmetry tracings were rated using categories of continuous, continuous fluctuating, interrupted, and prolonged. Other parameters included flow rate, voided volume, time to maximum flow, and voiding time. Agreement between raters is summarized with kappa (k) statistics and percentage where at least three raters agreed.

Results: The mean age of participants was 44.8 ± 18.3 years. Participant age categories were 18-24 years: 20%; 25-34 years: 17%; 35-64 years: 42%; 65+ years: 18%. Nine percent described their race as Asian, 31% Black, 62% White, and 89% were of non-Hispanic ethnicity. The interrater reliability was highest for the continuous flow category (k = 0.65), 0.47 for prolonged, 0.41 for continuous fluctuating, and 0.39 for interrupted flow curves. Agreement among at least three raters occurred in 74.3% of uroflow curves (69% for continuous, 33% for continuous fluctuating, 23% for interrupted, and 25% for prolonged). For intrarater reliability, the mean k was 0.72 with a range of 0.57-0.85.

Conclusions: Currently accepted uroflowmetry pattern categories have fair to moderate interrater reliability, which is lower for flow curves that do not meet "continuous" criteria. Given the subjective nature of interpreting uroflowmetry data, more consistent and clear parameters may enhance reliability for use in research and as a screening tool for LUTS and voiding dysfunction.

Trial registration: Parent trial: Validation of Bladder Health Instrument for Evaluation in Women (VIEW); ClinicalTrials.gov ID: NCT04016298.