Leither MD, et al. - In this retrospective study, researchers assessed mortality and renal events in relation to outpatient acute kidney injury (AKI), defined by a 50% increase in creatinine (Cr), in 384,869 adults receiving primary care at a health system. Five groups of patients were defined using outpatient serum Cr values obtained during an 18-month exposure period (no outpatient AKI, outpatient AKI with recovery, outpatient AKI without recovery, outpatient AKI without repeat Cr and no Cr). They used Cox proportional hazards models to determine all-cause mortality and renal events (50% decline in estimated glomerular filtration rate to <30 mL/min/1.73 m²). Participants were followed-up for 5.3 years. Findings revealed a greater prevalence of outpatient AKI than inpatient AKI (1.4% vs 0.3%). Outpatient AKI was identified as a risk factor for all-cause mortality and renal events, even among those who recovered kidney function.