Siew ED, Abdel-Kader K, Perkins AM, et al. - In this retrospective cohort analysis including 47,903 adult US veterans, researchers focused on the independent link between the timing of recovery from moderate to severe acute kidney injury (AKI) and future loss of kidney function. The participants had suffered stage 2 or 3 AKI, with recovery to within 120% of baseline creatinine level within 90 days of peak injury. The outcome was a continued 40% drop in estimated glomerular filtration rate below that estimated from the last serum creatinine level available during the 90-day recovery period or kidney failure. Recovery in 29,316 (61%), 10,360 (22%), 4,520 (9%), and 3,707 (8%) patients was seen within 1 to 4, 5 to 10, 11 to 30, and 31 to 90 days, respectively. A median observation period of 42 months revealed unadjusted incidence rates for the kidney outcome to be 2.01, 3.55, 3.86, and 3.68 events/100 person-years, respectively. Compared with 1 to 4 days, increased rates of the primary outcome were reported in relation to recovery within 5 to 10, 11 to 30, and 31 to 90 days: adjusted HRs were 1.33, 1.41, and 1.58, respectively. As far as AKI phenotyping and prognostic knowledge about the future occurrence of loss of kidney function was concerned, an added dimension was offered by the timing of recovery.