Urethral resistance factor (URA) versus Schäfer's obstruction grade and Abrams-Griffiths (AG) number in the diagnosis of obstructive benign prostatic hyperplasia.

Different methods of analyzing pressure/flow plots to quantify bladder outlet resistance in men with lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH) were developed in the past. The aims of this study were to quantify the degree of agreement between the diagnosis of obstruction by the different methods, and to compare the applicability of the different methods in the evaluation of bladder outflow conditions, in a large group of these men. In consecutive men with LUTS basic initial evaluations, recommended diagnostic tests, and urodynamic investigations were performed. From pressure/flow studies, the group-specific resistance factor (URA), Schäfer's obstruction grade, and Abrams-Griffiths (AG) number were estimated. Men with 21 cm H(2)O < or = URA < or = 29 cm H(2)O and men with Schäfer's grade equal 2 were classified as equivocal. In conformity with the provisional ICS definition, men with 20 < or = AG number < or = 40 were classified as equivocal. In 78% of the 565 included men Schäfer's classification agreed with URA classification. In 82% ICS classification agreed with URA classification. Most agreement (94%) existed between Schäfer's classification and ICS classification. All differences were near the points of intersection of the different boundaries, and a decision whether to perform surgery on a patient is not likely to be influenced by this disagreement. Males with relatively low detrusor pressure at maximum flow and relatively low maximum flow had a high prevalence among those in whom URA and Schäfer's classifications and among those in whom URA and ICS classifications differed. Copyright 2001 Wiley-Liss, Inc.