VARIABILITY OF CLINICAL AND PRESSURE-FLOW STUDY VARIABLES AFTER 6 MONTHS OF WATCHFUL WAITING IN PATIENTS WITH LOWER URINARY-TRACT SYMPTOMS AND BENIGN PROSTATIC ENLARGEMENT

Purpose: We quantified the physiological variability of clinical and p ressure-flow study variables in patients with symptomatic benign prost atic enlargement. Materials and Methods: Symptom scores were measured, and advanced urodynamic studies with pressure-flow analysis were perf ormed in 178 patients before and 6 months after a period of watchful w aiting. Results: Patients without bladder outlet obstruction experienc ed significant symptomatic improvement. Symptoms in patients with obvi ous bladder outlet obstruction did not improve significantly. The repr oducibility of mean pressure-flow variables was evident. However, ther e was an important intra-individual variability. Patients with obvious bladder outlet obstruction showed a significant decrease in detrusor pressure at maximal flow of 14 cm. water, a significant decrease in th e urethral resistance factor of 7 cm. water and a significant decrease of 1 obstruction class on the linear passive urethral resistance rela tion nomogram, indicating less severe bladder outlet obstruction. Conc lusions: Mean differences among therapy groups must be regarded critic ally, especially when the differences are slight and possibly within p hysiological variability.