Prognostic performance of plasma and urinary biomarkers of kidney injury and function after out-of-hospital cardiac arrest.

Abstract

Acute kidney injury (AKI) after out-of-hospital cardiac arrest (OHCA) portends worse outcomes, yet serum creatinine (sCr) underestimates injury. We evaluated whether kidney injury biomarkers improve early prediction of patient-centered outcomes and AKI after OHCA compared with sCr. In this prospective observational study, we measured plasma neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1) and cystatin C, and urinary NGAL and KIM-1 at 0, 24 and 72 h post-return of spontaneous circulation in comatose adult OHCA patients. The primary outcome was poor neurological recovery or mortality (Cerebral Performance Category (CPC) 3-5) at hospital discharge; secondary outcome was AKI. We compared biomarker distributions and discriminatory performance from areas under receiver operating characteristic curves (AUC). Among 82 patients (median age 59.5 years, 89.0% males), 45 (54.9%) had CPC 3-5 (39 died, CPC 5; 6 poor neurological recovery, CPC 3-4). AKI occurred in 54 (65.9%) patients, of whom 19 (23.2%) required renal replacement therapy. Patients in whom sCr rose by >20% (n = 33) and/or required dialysis had elevated biomarkers and a 71% CPC 3-5 incidence, versus 20% in those with decreasing by >20% (n = 23) or stable sCr (n = 7) (p < 0.001). Urinary NGAL was the strongest predictor for both CPC 3-5 (AUC 0.79 vs sCr 0.57) and AKI (AUC 0.81). Admission kidney biomarkers predicted AKI (AUCs 0.75-0.85) better than sCr (AUC 0.65). Kidney-specific biomarkers were superior to sCr for early AKI detection and prediction of patient-centered outcomes after OHCA. Early biomarker measurement may improve AKI and outcome risk stratification beyond conventional sCr-based assessment.