Aim: Acute kidney injury (AKI) is a common complication of medical and surgical interventions in hospitalized patients and associates with high mortality. Our aim was to examine renal recovery and long-term survival and time trends in AKI survival.
Methods: Changes in serum creatinine (SCr) were used to define AKI in patients at Landspitali University Hospital in Iceland from 1993 to 2013. Renal recovery was defined as SCr < 1.5× baseline.
Results: Out of 25 274 individuals who had their highest measured SCr during hospitalization and an available baseline SCr, 10,419 (41%) had AKI during hospitalization (H-AKI), 19%, 11% and 12% with Stage 1, 2 and 3, respectively. The incidence of H-AKI increased from 18.6 (95% CI, 14.7-22.5) to 29.9 (95% CI, 26.7-33.1) per 1000 admissions/year over the study period. Survival after H-AKI was 61% at 90-days and 51% at one year. Comparing H-AKI patients to propensity score matched individuals the hazard ratio for death was 1.49 (1.36-1.62), 2.17 (1.95-2.41) and 2.95 (2.65-3.29) for Stage 1, 2 and 3, respectively. One-year survival of H-AKI patients improved from 47% in 1993-1997 to 57% in 2008-2013 and the adjusted hazard ratio for mortality improved, compared to the first 5-year period, 0.85 (0.81-0.89), 0.67 (0.64-0.71), and 0.57 (0.53-0.60) for each subsequent 5-year interval. Recovery of renal function was achieved in 88%, 58% and 44% of patients in Stages 1, 2 and 3, respectively, improving with time.
Conclusions: Acute kidney injury is an independent predictor of long-term mortality in hospitalized patients but there has been a marked improvement in survival and renal recovery over the past two decades.
Keywords: Acute kidney injury; epidemiology; outcome; propensity score matching; renal recovery; survival.
© 2015 Asian Pacific Society of Nephrology.