Natural History of Postobstructive Nephropathy: A Single-Center Retrospective Study

Abstract

Background: There is extensive published material on the effects of experimental ureteric obstruction. In contrast, there is very little literature on the natural history of postobstructive renal disease in patients. Methods: Patients presenting with obstructive nephropathy and renal impairment in a tertiary renal unit, and whose obstruction was successfully relieved, were identified, and the Modification of Diet in Renal Disease equation was used to calculate the glomerular filtration rate (GFR) at presentation and after relief of obstruction. Results: 104 patients were identified (79 male). There were 9 deaths at 12 months and a further 4 deaths by 3 years; losses to follow-up were 7 and 20 at the same time points. The mean GFR was 9.2 ± (SEM) 0.9 ml/min at presentation (n = 104), 27.8 ± 1.7 ml/min at 3 months (n = 98), 29.0 ± 1.8 ml/min at 12 months (n = 79), and 30.0 ± 2.2 ml/min at 3 years (n = 61). Of 28 patients initially requiring dialysis, 6 were dialysis dependent at 3 months; 3 further patients, all with GFR <10 ml/min after relief of obstruction, required dialysis by 12 months and 1 further patient by 3 years. Conclusions: Progressive deterioration in renal function is unusual after relief of obstruction in the majority of patients over a 3-year period. This relative stability in human postobstructive nephropathy contrasts with the course of remnant nephropathy in animal models.