COMPARISON OF 3 METHODS OF QUANTIFYING URETHRAL RESISTANCE IN MEN

Objectives. To determine how well three methods of quantifying urethra l resistance from pressure-flow plots compared in men. Methods. The pr essure-flow plots of 312 men who attended a Continence Clinic for eval uation of lower urinary tract symptoms were analyzed. The Abrams-Griff iths number (AC), detrusor-adjusted mean PURR [passive urethral resist ance relation] factor (DAMPF), and group-specific urethral resistance factor (URA) were obtained for each plot. The correlation coefficients and simple regression equations were computed for AC versus DAMPF and AG versus URA. Using the provisional International Continence Society method for definition of obstruction to categorize the AG values as o bstructed, equivocal, or unobstructed, we obtained the corresponding D AMPF and URA values for our study population. Results. The Pearson cor relation coefficient, r, for AG versus DAMPF and AG versus URA was 0.9 41 and 0.889, respectively. The corresponding regression equations obt ained were AG = - 32.6 + (DAMPF) 1.27 (95% confidence interval [CI] 1. 22 to 1.32) and AC = - 16.4 + (URA) 1.67 (95% CI 1.58 to 1.77). The 5t h to 95th percentiles of the DAMPF and URA for men who were obstructed (AG number more than 40) were 56 to 92 and 28 to 71, those for men wh o were equivocal (AG 20 to 40) were 35 to 62 and 17 to 38, and those f or men who were unobstructed (AC less than 20) were 12 to 44 and 5 to 24, respectively. Conclusions. The DAMPF and URA were highly correlate d to the AG in a linear fashion. Although these parameters were develo ped differently, they appeared to compare well. When using the DAMPF o r URA to quantify urethral resistance, it was possible to estimate the corresponding AG value with reasonable confidence. (C) 1998, Elsevier Science Inc. All rights reserved.