Association between acute kidney injury and in-hospital mortality in patients undergoing percutaneous coronary interventions

Abstract

Acute kidney injury (AKI) post percutaneous coronary intervention (PCI) is associated with increased mortality but both death and AKI share common risk factors. Moreover, the effect of a high contrast dose, a known modifiable risk factor for AKI, on mortality is unknown. The aim of our study was to analyze the association between AKI and in-hospital mortality post PCI after adjustment for confounding by common risk factors. Methods and Results-This study was performed using a regional registry of all patients undergoing PCI in Michigan. Primary end points were AKI (serum creatinine increase >0.5 mg/dL) and all-cause in-hospital mortality. Propensity matching was performed, with each AKI patient matched to 4 controls. Attributable risk fraction and the exposed index number of AKI for mortality were calculated within the propensity-matched cohort. Between 2010 and 2013, 92 317 patients underwent PCI, of whom 2141 (2.3%) developed AKI. We matched 1371/2141 patients with AKI to 5484 controls. AKI was strongly associated with mortality (odds ratio=12.52, 95% confidence interval 9.29-16.86) in the propensity-matched cohort. The attributable risk fraction for mortality of AKI was 31.4% (95% confidence interval 26.8%-37.5%), and one death could be prevented for every 9 cases of AKI successfully avoided. The independent impact of a high contrast dose at time of PCI on in-hospital mortality risk was weak (adjusted odds ratio 1.19, 95% confidence interval 0.97-1.45). Conclusions-Nearly one-third of the in-hospital mortality post PCI is attributable to AKI. Preventing 9 cases of AKI couldpotentially prevent one death. These study findings stress the need for developing effective AKI preventive strategies beyond minimization of contrast dose.