Impact of acute kidney injury on patient outcome in out‐of‐hospital cardiac arrest: a prospective observational study

Background Kidney disease after out‐of‐hospital cardiac arrest ( OHCA ) is incompletely described. We examined the occurrence of acute kidney injury ( AKI ) in OHCA patients and impact of AKI , with or without renal replacement therapy ( RRT ), on 6‐month mortality and neurological outcome. Methods Prospective study at Oslo University Hospital, Oslo, Norway. Adult resuscitated comatose OHCA patients treated with targeted temperature management at 33°C for 24 h were included. AKI and chronic kidney disease ( CKD ) were classified according to the Kidney Disease Improving Global Outcomes ( KDIGO ) guidelines. Main outcomes were 6‐month mortality and good neurological outcome defined as Cerebral Performance Category 1–2. Results Among 245 included patients (84% males, mean age 61 years), 11 (4%) had previously known CKD and 112 (46%) developed AKI . Overall 6‐month outcome revealed that 112 (46%) died and 123 (50%) had good neurological outcome. Compared with no kidney disease, the presence of AKI was significantly associated with 6‐month mortality (odds ratio ( OR ) 3.17, 95% confidence interval ( CI ) 1.95–5.43, P < 0.001) and good neurological outcome ( OR 0.28, 95% CI 0.16 – 0.48, P < 0.001). Six‐month mortality (50 vs. 61%, P = 0.401) and frequency of good neurological outcome (44 vs. 35%, P = 0.417) were not statistically different in AKI patients with or without RRT , also after excluding patients where RRT was withheld due to futility. Conclusions Kidney disease occurred in about half of patients successfully resuscitated from OHCA . Presence of AKI , but not RRT , was associated with unfavourable 6‐month outcome.