Even Stage 1 AKI Increases CKD Risk

Even in mild cases with fast recovery, acute kidney injury (AKI) developing in the hospital is a strong risk factor for chronic kidney disease (CKD) at follow-up, reports a study in The American Journal of Kidney Diseases.

Using Veterans Health Administration data for 2011, the investigators identified nearly 105,000 hospitalized patients with normal baseline kidney function, no diagnosed kidney disease, and at least 2 inpatient serum creatinine measurements. With varying follow-up times, the risk of CKD associated with AKI was analyzed. The analysis included not only the stage of AKI, but also the pattern of recovery: within 2 days (fast), 3 to 10 days (intermediate), and no recovery within 10 days (slow or unknown).

Ninety-one percent of AKI episodes were stage 1; recovery occurred within 2 days in 71% of cases. By one year, CKD had developed in 18.2% of patients: 31.8% of those with AKI versus 15.5% without AKI. Among patients with stage 1 AKI, risk of CKD increased with time to recovery. Adjusted relative risk ratio for CKD stage 3 or higher was 1.43 for fast, 2.00 for intermediate, and 2.65 for slow/unknown recovery. The relative risks were about the same on subgroup and sensitivity analyses.

In this cohort of veterans, inpatient AKI is associated with an elevated risk of developing CKD during follow-up. The risk is significant even for the large group of patients with stage 1 AKI, and increases further with longer time to recovery. The authors discuss the implications for postdischarge follow-up of patients with inpatient AKI [Heung M, et al. Acute kidney injury recovery pattern and subsequent risk of CKD: an analysis of Veterans Health Administration data. Am J Kidney Dis 2016; 67:742–752].