Maximum Flow Rate — The Single Uroflowmetric Parameter in Clinical Trials for Benign Prostatic Hyperplasia?

Background Uroflowmetry parameters should be examined for both reliability and optimal test conditions in patients with benign prostatic hyperplasia (BPH), since the difference between one pre‐ and one post‐intervention uroflow rate is usually evaluated in clinical trials of BPH. Patients and Methods: Reproducibility of maximum flow rate ( Q max ) or its modified forms, and the effects of urinary volume on the reproducibility were examined in terms of Spearman's correlation coefficient (r) in 67 BPH patients. Results: Q max had a higher r (0.672) as compared to other uroflow rates, such as mathematically modified forms of Q max and adjusted values of Q max on nomograms. Reliability was improved by bladder instillation ( r = 0.811) or when voided volume was ≥ 150 ml or the ratio of volumes was < 2.0 ( r = 0.690–0.736). Conclusion(s): Q max , preferably performed with urinary volumes of more than 150 ml or the ratio of volumes less than 2.0, is the most practical single parameter at present in the comparison of two uroflowmetric tests in BPH treatment.