The precise incidence of acute kidney injury (AKI) in the paediatric age group is unknown, partly due to the lack of a universally agreed definition in the past. We conducted this study to assess incidence of AKI among hospitalised children on World Kidney Day 2016.

Cross-sectional study involving 8 tertiary paediatric centres across England, Scotland, Wales and Northern Ireland. Centres reported numbers of new cases of AKI on a single observation day, associated clinical features and follow-up data where available. Cases were defined according to the KDIGO (Kidney Disease: Improving Global Outcomes) AKI definition.

On the observation day, there were 1218 inpatients in 8 centres. Thirty-one children (2.5%) met the case definition for AKI. The majority of patients had no pre-existing, known risk factors for AKI (20/31, 65%), while the leading known risk factor was congenital heart disease (5/31, 15%). Most cases of AKI were hospital acquired (25/31, 81%). The leading contributory factors were: medications (13/31, 42%), hypotension/shock (10/31, 32%) and dehydration (10/31, 32%). AKI was subdivided according to severity: stage 1 (25/31, 81%), stage 2 (2/31, 6%) and stage 3 (4/31, 13%). Follow-up results at 7 days were available for all 31 cases. Renal replacement therapy was required in 2 cases (6%). Recovery from AKI at 7 days was: complete (18/31, 58%), incomplete (9/31, 29%) or unknown (4/31, 13%); 2 patients (6%) died from non-renal causes.

This is the first study looking at the point incidence of AKI in hospitalised paediatric patients according to the KDIGO AKI classification. Our estimated point incidence of 2.5% is similar to international reports. The majority of cases were hospital acquired and the leading contributory factor was nephrotoxic medication, a significant modifiable factor. Further prospective studies will be necessary to evaluate the benefit of interventions designed to reduce the incidence of AKI in paediatrics.