Aki

Abstract

AKI is a common syndrome, with a population-based incidence estimated to have grown from 3000 to .5000 episodes per million person-years during the past 2 decades in the United States (1). The immediate prognostic implications of AKI are well established and include prolonged hospitalization, the need for acute RRT, and high mortality. The increasing incidence of AKI, coupled with the fact that adjusted hospital mortality has decreased by approximately 60% among patients with the condition, has increased the number of individuals discharged from the hospital after experiencing an episode of AKI. This has raised questions as to whether AKI may have long-term health implications. Although most survivors of AKI have partial or complete recovery of kidney function by the time of hospital discharge (2), several recent observational studies examining the long-term course of AKI suggest that outcomes can encompass a spectrum that includes progressive loss of kidney function, CKD, and ESRD (3). This suggests that individuals who survive an episode of AKI may also be at risk of downstream complications of CKD, including cardiovascular events and late mortality.In this issue of CJASN, Chawla et al. compare subsequent mortality, cardiovascular, and kidney outcomes between individuals hospitalized with myocardial infarction (MI), AKI, and the combination of MI and AKI (4). They studied 36,980 patients hospitalized in the US Department of Veterans Affairs with primary discharge diagnoses of AKI or MI, mean baseline eGFR$45 ml/min per 1.73 m 2 , and serum creatinine measurements both before and during admission. Using combinations of International Classification of Diseases Ninth Revision-Clinical Modification codes for MI and AKI, augmented with serum creatinine measures to define AKI according to the Kidney Disease: Improving Global Outcomes (KDIGO) definition, three groups of interest were identified: (1) a group with a primary diagnosis of MI without an increase in serum creatinine indicating AKI, (2) a group with a primary diagnosis code for AKI and an increase in serum creatinine indicating AKI, and (3) a group with a primary diagnosis of MI and an increase in serum creatinine indicating AKI. This study focused on several composite outcomes that have been proposed for clinical trials in AKI, including the composite of major adverse kidney events (defined as chronic dialysis, a 25% decline in eGFR, or death), major adverse cardiac events (defined as a subsequent admission for stroke, MI, or congestive heart failure), and major adverse renal cardiovascular events (a composite of all of these events), over a median followup of 1.4 years after hospital admission.The investigators compared outcomes with a reference group with MI alone and noted that those with a primary diagnosis of AKI had a 37% increase in the relative risk of a composite major adverse renal or cardiovascular event, whereas those with MI and serum creatinine changes of AKI had a 92% increase. Further examination of the components of this composite showed t...