Abstract 13975: Association of In-Hospital Acute Kidney Injury With Long-term Outcomes in Survivors of Acute Myocardial Infarction: Insight From the NCDR

Abstract

Background: Chronic kidney disease (CKD) and acute kidney injury (AKI) have both been associated with adverse short-term outcomes after MI. However, the impact of AKI on long-term outcomes and the interaction of AKI with baseline renal function have not been well described. Methods: ACTION Registry®-GWTGTM records from 2008-2012 were linked to Medicare data yielding a population of 76,500 acute MI patients from 581 hospitals who survived to hospital discharge. We excluded patients with cardiogenic shock, cardiac arrest, and those undergoing CABG or currently on dialysis. CKD status was defined using the Kidney Disease Outcome Quality Initiative criteria based on admission GFR estimated using the MDRD equation. No, mild, moderate and severe AKI were defined as changes in creatinine (Cr) from baseline to peak of < 0.3, 0.3 to < 0.5, 0.5 to < 1.0 and ≥ 1.0 mg/dl respectively. Cox proportional hazard modeling was used to examine associations between AKI and 1-year mortality. Covariates for risk adjustment were adapted from the CRUSADE long-term mortality risk model. Results: The median age was 77 years, 30% had STEMI and 78% underwent diagnostic angiography.The incidence of mild, moderate and severe AKI was 7.5%, 6.0% and 3.0%. CKD stages 3, 4, and 5 were present in 41.2%, 6.7%, and 1.0% of patients. Both CKD and AKI were significantly associated with 1-year mortality (p< 0.0001 for each). A significant interaction was noted between CKD and AKI with respect to 1-year mortality (p-interaction<0.0001). Adjusted 1-year mortality increased in a dose-dependent manner across increasing severity of AKI, but this association was attenuated among individuals with more severe baseline CKD (Figure). Conclusion: One-year mortality increased in proportion to severity of AKI, with even a small increase in Cr associated with worse outcomes. The association of AKI with outcomes was modified by baseline Cr, with a greater impact of AKI observed among patients with higher baseline eGFR.