Can urodynamic assessment of outflow obstruction predict outcome from watchful waiting?--A four-year follow-up study

One of the most common "treatment" alternatives in suspected outflow obstruction due to bladder outlet obstruction (BOO) is watchful waiting (WW). The aim of this study was to see whether there were any differences in outcome between patients with slight, moderate or severe obstruction due to BOO as classified by transrectal ultrasound (TRUS) and urodynamics.

Thirty-seven men with lower urinary tract symptoms (LUTS) and suspected BOO were included. All of the patients were investigated by a routine investigation schedule, including TRUS and urodynamics with pressure-flow measurement (pQS) at baseline. Patients with cancer in the urinary tract, prostatitis, history of detrusor hyperreflexia (peripheral or central diseases or trauma to the nervous system affecting the bladder) and serious systemic diseases were excluded. Patients were examined at baseline, then checked again after 1 year and 4 years. Patients who did not want to continue with WW were listed as treatment failures.

At baseline, 43.2% of the patients were urodynamically severely obstructed and 32.3% were moderately obstructed. Thirty-five per cent of the patients were found to have previously unknown detrusor hyperactivity/overactivity. The prevalence of detrusor hyperactivity/overactivity increased with BOO. After 1 year, IPSS had decreased at unchanged Qmax and postresidual volume. These findings persisted at 4 years. The failure rate increased in the more obstructed patients and was significantly higher with more severe obstruction. Complications were found in 13.5%, with no significant differences between patients with minor BOO [Detrusor Adjusted Mean PURR Factor (DAMPF) scale <42], moderate BOO (DAMPF 42-65) and severe BOO (DAMPF >65).

In patients with severe BOO, the LUTS and failure rate increase over time. The percentage of patients with detrusor hyperactivity/overactivity was higher in the severely obstructed group. By including full urodynamics when investigating patients with BOO, it seems possible to predict the failure rate according to the patients' obstruction grade. This gives an opportunity to treat the patient with minimal invasion, and to give the individual patient a more precise prognosis if WW is preferred.