Acute pyelonephritis in children and the risk of end-stage kidney disease.

Background Pyelonephritis is the most common serious bacterial infection during childhood. The long-term importance of kidney scarring is unclear. Objective To assess the risk of end-stage kidney disease (ESKD) in adolescents and young adults with history of pyelonephritis. Study design A nationwide, population-based, historical cohort study, including 1,509,902 persons (62% male) examined for military service between 1967 and 1997. Participants with a history of pyelonephritis were sub-grouped according to presence of kidney scarring and baseline kidney function. Data were linked to the Israeli ESKD registry to identify incident ESKD cases. Cox proportional hazards models were used to estimate the hazard ratio (HR) of treated ESKD (dialysis or kidney transplant). Results Pyelonephritis was diagnosed in 6979 participants (0.46%). 6479 had normal kidney function and no evidence of kidney scarring, 400 had normal kidney function with evidence of scarring, and 100 demonstrated reduced baseline kidney function. Treated ESKD developed in 2352 individuals (0.2%) without history of pyelonephritis, 58 individuals (0.9%) with normal kidney function, history of pyelonephritis and no kidney scarring, 14 individuals (3.5%) with normal kidney function, history of pyelonephritis and kidney scarring, and 23 individuals (23.0%) with history of pyelonephritis and reduced baseline kidney function, yielding HR of 3.3, 34.8 and 43.2, respectively, controlling for age, gender, paternal origin, enrollment year, body mass index, and blood pressure, and accounting for death as a competing risk. Conclusion History of pyelonephritis was associated with significantly increased risk of treated ESKD, particularly when associated with kidney scarring or reduced baseline kidney function.