Abstract
BACKGROUND: There is a gap of knowledge in the long-term outcomes of patients who have complete recovery of kidney function after an episode of acute kidney injury (AKI). We sought to determine whether complete recovery of kidney function after an episode of AKI is associated with the development of incident stage 3 chronic kidney disease (CKD) and mortality in patients with normal baseline kidney function. DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: 3,809 patients from an integrated health care delivery system who had a hospitalization between January 1, 1999, and December 31, 2009, with follow-up through March 31, 2010. PREDICTOR: AKI defined by International Classification of Diseases, Ninth Revision (ICD-9) codes and using the AKI Network (AKIN) definition, with complete recovery defined as a decrease in serum creatinine level to less than 1.10 times the baseline value. OUTCOMES AND MEASUREMENTS: Incident stage 3 CKD persistent for 3 months and all-cause mortality. RESULTS: After a median follow-up of 2.5 years, incident stage 3 CKD occurred in 15% and 3% of those with and without AKI, respectively, with an unadjusted HR of 5.93 (95% CI, 4.49-7.84) and HR of 3.82 (95% CI, 2.81-5.19) in propensity score-stratified analyses. Deaths occurred in 35% and 24% of those with and without AKI, respectively, with an unadjusted HR of 1.46 (95% CI, 1.27-1.68). In propensity score-stratified analyses, HR decreased to 1.08 (95% CI, 0.93-1.27). LIMITATIONS: Measurements of albuminuria were not available. CONCLUSIONS: Complete recovery of kidney function after an episode of AKI in patients with normal baseline kidney function is associated with increased risk of the development of incident stage 3 CKD, but not all-cause mortality.