In light of the changing trends in the etiology of pediatric acute kidney injury (AKI), a clearer understanding of the long-term outcomes of this condition would allow optimization of follow-up strategies.OBJECTIVE
To characterize the long-term incidence of death and residual renal injury in children after an episode of AKI.DESIGN AND INTERVENTION
Children who were treated for AKI at Texas Children's Hospital between January 1998 and June 2001 were included in this retrospective cohort study if they were alive at the time of discharge, if their discharge or death summary cited a diagnosis of acute renal failure (ARF), and if they had an estimated glomerular filtration rate (GFR) of ≤75 ml/min/1.73 m2. Chronic kidney disease and prior kidney transplantation were exclusion criteria. Patient and kidney survival was determined by questioning physicians, and by searching data held at the study center and at the Texas Department of Health. Surviving patients with a functioning kidney who consented to participate in the study received one follow-up visit, during which four measures of renal injury were evaluated-estimated creatinine clearance (calculated using the Schwartz equation), spot urine albumin:creatinine ratio, hematuria and blood pressure. The PedsQL® (James W Varni, College Station, TX) 4.0 Generic Scale questionnaire was used to evaluate health-related quality of life.OUTCOME MEASURES
The main endpoints were patient survival, kidney survival, hyperfiltration (creatinine clearance >150 ml/min/1.73 m2), reduced creatinine clearance (<90 ml/min/1.73 m2), microalbuminuria (spot urine albumin:creatinine ratio ≥30), hematuria and blood pressure.RESULTS
Among the 174 children who survived hospitalization, 139 (79.9%) were alive and 158 (90.8%) had functioning kidneys 3-5 years later. Mortality was highest in the first year after transplantation (68.6%). When the 71 deaths that occurred during hospitalization were taken into account, the overall 3-5-year survival rate was 56.7% (139/245). Kidney survival was significantly lower in patients with primary renal or urologic disorders than in those who had other causes of renal failure (68.6% vs 95.7%; P<0.0001). Of the 126 children who were alive with a functioning kidney at the time of the follow-up study, 29 agreed to take part. Patient demographics, duration of hospitalization and clinical status at discharge were similar in the children who did and did not take part in the study. The etiologies of AKI among participants included primary renal conditions (n = 4), nephrotoxic injury (n = 3) and acute tubular necrosis/sepsis/hemorrhage (n = 11). Evidence of kidney damage was noted in 17 (58.6%) patients; hyperfiltration in 9, reduced GFR in 4, microalbuminuria in 8, hematuria in 1 and elevated blood pressure in 6. Of these children, 6 (35.3%) were receiving ongoing care from a pediatric nephrologist. Quality of life in the study population was similar to that in healthy children.CONCLUSION
Death and renal sequelae are common outcomes of pediatric AKI, regardless of etiology. Children should be monitored regularly for kidney damage after an episode of AKI.