Estimate criteria for diagnosis and severity in benign prostatic hyperplasia

Standard severity criteria for benign prostatic hyperplasia (BPH) are needed to facilitate clinical and epidemiologic investigations in the common terminology.

A total of 692 BPH patients from 8 institutions were judged by specialized physicians for their overall disease severity and severity in 4 domains: symptom, function, anatomy, and quality of life (QOL). The items measuring severity in these 4 domains were the International Prostate Symptom Score (I-PSS) questionnaire, uroflowmetry, transrectal ultrasonography (TRUS), and questionnaires on bother and I-PSS QOL index, respectively. By Spearman's rank correlation and multiple regression analysis using physicians' judgement as the criterion variable (gold standard) the items and their cut-off levels were selected so that high predictivity, practicality and clinical significance were maintained, while the number of items in use was minimized.

The item(s) and their ranges of values for each severity grade were summarized as follows; the evaluation domain (the selected item(s): range of mild, moderate, severe): symptom (I-PSS: 0-7, 8-19, 20-35), function (maximum flow rate and residual urine volume: > or = 15 mL/s and < 50 mL, > or = 5 mL/s and < 100 mL, < 5 mL/s or > or = 100 mL), anatomy (prostate volume on TRUS: < 20 mL, < 50 mL, > or = 50 mL), QOL (QOL index: 0 and 1, 2 to 4, 5 and 6). The overall severity was efficiently predicted when defined according to the combinations of severity grades of the 4 domains. These criteria predicted physicians' judgement with accuracy of about 80% for overall severity and severity of individual domains.

The proposed criteria are valid, practical, and would be useful for the common scale of the BPH severity in clinical and epidemiologic studies.