Renal function 16 to 26 years after the first urinary tract infection in childhood

Abstract

Objective: To evaluate renal function in a population-based cohort with urographic renal scarring after childhood urinary tract infection (UTI).

Design: Follow-up investigation 16 to 26 years after the first recognized UTI.

Setting: Outpatient university clinic for children with UTI serving the local area.

Patients: From the original cohort of 1221 consecutive children with first UTI diagnosed during 1970 to 1979, 57 (41 females and 16 males; mean age, 24.5 years) of 68 with nonobstructive renal scarring participated as well as 51 (38 females and 13 males; mean age, 24.9 years) matched subjects without scarring.

Main outcome measure: Glomerular filtration rate (GFR) measured by chromium 51-EDTA clearance, expressed as milliliters per minute per 1.73 square meters.

Results: Median GFR was 99 in both those with and without renal scarring. In patients with unilateral scarring, the total GFR remained unchanged over the years whereas the individual GFR of the scarred kidneys declined significantly from 46 to 39. In 7 patients with bilateral scarring, the GFR declined from 94 to 84 (P = .14); compared with those with unilateral scarring, the GFR was significantly lower at follow-up (P = .007). Median urinary albumin-creatinine ratio was 1.2 and 0.6 mg/mmol in those with scarring and those without, respectively (P = .30).

Conclusions: The GFR 2 decades after the first recognized UTI in childhood was well preserved. However, a significant reduction of individual renal GFR in the unilaterally scarred kidneys indicates that further follow-up is required. Although there were few patients with bilateral scarring, a more serious prognosis can be expected among them.