An Objective Uroflowmetry Curve Score and Five Descriptive Curve Groups in Men: A Single-Centre Retrospective Study

Uroflowmetry curve shape is judged by eye, with only fair-to-moderate agreement between readers. We aimed to describe male flow curves objectively with one score and a few descriptive groups that other centres can compute.

Retrospective single-centre study of male free uroflowmetry (voided volume ≥ 150 mL; 2022-2026). Seven measures described each curve: four from the report (maximum flow rate [Qmax], flow time, time to Qmax, average flow) and three from the stored curve (flow dips, variability, plateau). The score was their first principal component; five descriptive groups were formed by k-means clustering. Age, a benign prostatic hyperplasia (BPH) label and post-void residual (PVR), not used to build either, served as checks.

We analyzed 2414 examinations from 2154 identified men (median age 64 years). The score captured 37% of variation. Groups ranged from low, prolonged, fluctuating curves (group A, 11%) to bell/plateau (D, 27%) and brisk, peaked curves (E, 22%). The score fell with age (Spearman ρ = -0.21; Qmax alone: -0.19) and PVR (ρ = -0.35, n = 465); median PVR was 89 mL in group A versus 23 mL in D. BPH labeling did not differ between groups (p = 0.12). A report-values-only score correlated 0.91 with the full score.

The score and groups give an objective, shared description of male curve shape for research and audit. The five groups describe a continuum of curve shapes, with no clear-cut boundaries between them. They track age and PVR about as strongly as Qmax and are not a diagnostic test. Constants, a worked example and code are provided.