REPRODUCIBILITY OF PRESSURE-FLOW VARIABLES IN PATIENTS WITH SYMPTOMATIC BENIGN PROSTATIC HYPERPLASIA

Objectives. To study the reproducibility of pressure-flow studies in p atients with symptomatic benign prostatic hyperplasia and to investiga te if the reproducibility is influenced by the method of intravesical pressure measurement, that is, transurethral catheterization versus su prapubic puncture. Methods. The within-patient variation of maximum ur inary flow rates and detrusor pressure at maximum flow was investigate d in 25 patients in whom 2 (transurethral group) or 3 (suprapubic grou p) sequential voidings during urodynamic investigation were analyzed. Results. The within-patient variation of pressure-flow values was eval uated by the intraclass correlation coefficient, which was 0.71 for ma ximum urinary flow rate and 0.84 for detrusor pressure, suggesting a r elatively high degree of reproducibility. However in 26% of the patien ts, the maximum flow rates changed by more than 3 mL/s or the detrusor pressure by more than 20 cm H2O during the repeated tests, There was no significant difference in the within-patient variation of pressure- few values between the suprapubic group and the transurethral group. C onclusions. In larger clinical trials where the assessment of treatmen t effects between groups is desired, a single pressure-flow test is su fficient. In the individual patient, a single pressure-flow curve is o f limited value due to a considerable within-patient variation of the test and, for these patients, multiple consecutive tests are recommend ed for diagnosis of intravesical obstruction and assessment of individ ual patient's response to treatment.