Comparison of patients' assessment of urinary flow strength with uroflowmetry.

Objective: The objective of the study was to compare patients' self-assessment of urinary flow strength with uroflowmetry.

Methods: The study was set in the routine uroflow clinic of the urology department. All patients had symptoms of bladder outlet obstruction. They answered 2 questions and a multiple-choice pictorial representation of flow trajectory. Patients were encouraged to provide 3 flows with at least one volume over 150 ml. The maximum flow rate Qmax was compared with the subjective evaluations.

Results: Qmax was normally distributed. Answers to the questions did separate patients significantly (p < 0.001). However, overlap between groups was large; the group who answered that their flow was poor included many false positives. Pictorial assessment showed low correlation with Qmax, again with a high false-positive rate.

Conclusion: Patients' self-assessment of strength of stream is unreliable as a measure of Qmax and therefore of obstruction. Resection of prostate on history alone is not recommended.