Trends in acute kidney injury and outcomes after early percutaneous coronary intervention in patients ≥75 years of age with acute myocardial infarction.

We analyzed the Nationwide Inpatient Sample database from 2002 to 2010 to examine the temporal trends in incidence of acute kidney injury (AKI), AKI requiring dialysis, and associated in-hospital mortality in patients ≥75 years of age hospitalized with acute myocardial infarction and undergoing early (within 24 hours) percutaneous coronary intervention. Of 2,225,707 patients ≥75 years of age with acute myocardial infarction, 233,508 (10.5%) underwent early percutaneous coronary intervention, of which 21,961 (9.4%) developed AKI and 1,257 (0.54%) developed AKI requiring dialysis. From 2002 to 2010, the incidence of AKI increased from 5.6% to 14.2% (p for trend <0.001) and that for AKI requiring dialysis decreased (0.6% to 0.4%; p for trend 0.018). Compared with 2002, multivariable-adjusted odds ratios and 95% confidence intervals for AKI, AKI requiring dialysis, and in-hospital mortality in 2010 were 1.87 (1.71 to 2.05), 0.20 (0.15 to 0.27) and 0.74 (0.60 to 0.90), respectively. In conclusion, among hospitalized adults ≥75 years of age, from 2002 to 2010, there was an increase in AKI, but there was paradoxical decrease in AKI requiring dialysis and in-hospital mortality, potentially reflecting increased health-care provider awareness resulting in early recognition and implementation of renal-protective strategies and diagnosis-related group creep.