Progression of acute kidney injury to chronic kidney disease: a prospective cohort study.

Background: Prospective studies on kidney outcomes in critically ill children with acute kidney injury (AKI) are scarce from low- and middle-income countries (LMIC). We conducted a pilot study to evaluate the continuum of transient AKI-persistent AKI-acute kidney disease (AKD) and chronic kidney disease (CKD).

Methods: Children (1-18 years) admitted to our tertiary Pediatric Intensive Care Unit (PICU) and developing AKI with no known pre-existing kidney co-morbidities from January 2021 to June 2022 were included with follow up visits at 1 and 3 months after AKI onset. AKI and CKD were defined as per KDIGO 2012. At risk of CKD was defined by albuminuria, hypertension, estimated glomerular filtration rate (eGFR) 60-90 ml/kg/1.73 m² or hyperfiltration (eGFR ≥ 150 ml/kg/1.73 m²).

Results: Of 390 children, 15% (n = 57) developed AKI. 75% (n = 43) with AKI had underlying primarily non-kidney systemic etiology. Fourteen (25%) died at median 5 days (IQR 4-7) after admission, and three were lost to follow up after discharge. For the 40 AKI survivors with three months data, incidence of transient AKI was 40% (n = 16), persistent AKI 20% (n = 8), AKD 32% (n = 13), and CKD 8% (n = 3). In addition, 18% (n = 7) were at risk of CKD. 38% with AKI for > 48 h vs. 6% with AKI < 48 h developed CKD or were at risk of CKD (p = 0.025). All three AKI survivors who progressed to CKD had an underlying primarily kidney etiology and progressed from AKD to CKD.

Conclusions: In this LMIC study, kidney sequelae were high at 3 months among PICU AKI survivors. This pilot supports the need and feasibility of larger prospective trials in LMIC settings to understand outcomes for all children with AKI.