Protracted recovery from moderate to severe acute kidney injury (AKI) is associated with a higher risk for advanced chronic kidney disease (CKD) or kidney failure, according to new study findings published in the American Journal of Kidney Diseases.

Edward D. Siew, MD, of the VA Tennessee Valley Health System in Nashville, and colleagues examined outcomes for 47,903 male US veterans with a first episode of stage 2 or 3 AKI not requiring dialysis who recovered to within 120% of their baseline creatinine level within 90 days. The primary study outcome was a sustained 40% decline in estimated glomerular filtration rate (below that calculated from the last serum creatinine level available during the 90-day recovery period) or kidney failure.

Of the 47,903 patients, 61%, 22%, 9%, and 8% recovered within 1 to 4, 5 to 10, 11 to 30, and 31 to 90 days, respectively. Among patients without CKD, recovery within 5 to 10, 11 to 30, and 31 to 90 days was associated with significant 36%, 39%, and 61% increased risks for the primary outcome, respectively, in adjusted analyses compared with recovery in 1 to 4 days. For patients with pre-existing CKD, recovery within 5 to 10, 11 to 30, and 31 to 90 days was associated with significant 28%, 31%, and 37% increased risks of the primary outcome, respectively, compared with recovery in 1 to 4 days.

Over a median 42 months, unadjusted incidence rates for the outcome were 2.01, 3.55, 3.86, and 3.68 events per 100 person-years, during each recovery time period, respectively.

“Our findings suggest that the pattern and duration of recovery, especially when extending beyond discharge, is an additional factor that can further aid in risk stratification and guide clinical care, such as referral for specialty care. This may be especially true in patients with elevated baseline risk, for whom we observed that the increase in absolute risk resulting from delayed recovery was largest,” Dr Siew’s team stated.

The study’s limitations included the dearth of female patients and a lack of information on the cause of AKI.

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Reference

Siew ED, Abdel-Kader K, Perkins AM, et al. Timing of recovery from moderate to severe AKI and the risk for future loss of kidney function [published online September 16, 2019]. Am J Kidney Dis. doi:10.1053/j.ajkd.2019.05.031