Severity of Acute Kidney Injury Predicts Risk of Incident Chronic Kidney Disease

More acute kidney injury (AKI)—especially requiring dialysis—is a strong and independent predictor of progression to stage 4 chronic kidney disease (CKD), reports a study in Kidney International.

Department of Veterans Affairs Healthcare System data were used to identify 5351 patients who had a primary diagnosis consistent with AKI. Of these, 728 developed stage 4 CKD after hospitalization. An exploratory analysis evaluated three multivariate models to predict progression to stage 4 CKD. The predictive value of the models was then confirmed in a validation stage that included 11,589 patients hospitalized for myocardial infarction or pneumonia during the same period—all with RIFLE codes R, I, or F plus complete data for all predictor variables.

All three multivariate models were significant, with c statistics of 0.82, 0.81, and 0.77. All models showed good predictive accuracy in the validation stage, with c statistics of 0.81–0.82. Factors associated with poor long-term renal outcomes included advanced age, low serum albumin, presence of diabetes, and severity of AKI, based on either RIFLE score or mean serum creatinine levels during hospitalization.

Patients who required dialysis during their episode of AKI and subsequently recovered were at particularly high risk of progressing to stage 4 CKD. In the validation phase, patients who required renal replacement therapy had a 500-fold increase in likelihood of progression to CKD.

Severity of AKI, among other factors, predicts the risk of progression to CKD in an incident AKI population. Patients who require dialysis and then recover seem to be at particularly high risk, requiring follow-up after hospital discharge. The researchers call for further study to refine the risk equations and evaluate potential interventions [Chawla LS, et al. The severity of acute kidney injury predicts progression to chronic kidney disease. Kidney Int 2011; 79:1361–1369].

August 2011 (Vol. 3, Number 8)