Bladder dysfunction as a prognostic factor in patients with posterior urethral valves

To investigate the extent to which different types of bladder dysfunction can affect long-term renal function in boys with posterior urethral valves (PUV).

Renal and bladder function were retrospectively assessed in 59 boys with PUV (mean age 10 years, range 5-17). All patients included in the study had at least 4 years of follow-up and their bladder behaviour had been evaluated in at least two urodynamic studies. At the time of the study, of the 59 PUV boys, 37 had normal renal function and 22 had end-stage renal disease (ESRD).

Of the 59 boys with PUV evaluated by urodynamic studies, 25 had normally behaving bladders (42%) and 34 had some type of bladder dysfunction (58%). Of the 22 in ESRD, 15 had abnormally behaving bladders (68%) and only seven had bladders with normal behaviour (32%). Of the 37 boys with normal renal function, 19 had dysfunctional bladders (51%) and 18 had normal bladders (49%). Instability was found in 17 of 19 boys with bladder dysfunction and normal renal function. On the contrary among 22 boys with ESRD, poor compliance was the most frequent urodynamic pattern (eight, 53%) while instability was only found in five. Overall, eight of nine boys with poorly compliant bladders, two of three with myogenic failure and a five of 22 with instability were in ESRD, and this situation occurred at an earlier age in patients with poorly compliant bladders.

Bladder dysfunction should be considered as a prognostic factor in renal failure. Those with poor bladder compliance and myogenic failure have the worst outcome, while bladder instability was associated with the lowest incidence of renal failure.