Outcomes of community-acquired acute kidney injury: a prospective comparative cohort study

Prospective studies on the clinical course and outcome of community-acquired acute kidney injury (CA-AKI) are lacking. We hypothesized that similar to patients with hospital-acquired AKI, CA-AKI patients experience adverse outcomes when compared with a control group of non-AKI patients. This was a prospective comparative cohort study in which serum creatinine (SCr) of all individuals visiting a university hospital's emergency (ED) over an 11-month period were examined for the presence of AKI. A total of 512 AKI cases (48% women) were identified, and 1024 control cases matched on age, sex and time of ED visit (1:2) were randomly selected. Following the visit, the participants were monitored through electronic medical records for up to 15 months, and hospital outcomes, serum SCr measurements and mortality were evaluated. The mean (±SD) age of AKI cases and controls was 67.1 ± 16.6 years and 67.2 ± 16.2 years, respectively. Compared with the control group, AKI cases were more likely to require hospitalization (77.1% vs. 59.9%, p < 0.001), had longer hospital stay (4 days [IQR 1-10] vs. 2 days [IQR 0-5], p < 0.001), higher 90-day mortality (AKI stage 1: HR 2.35, 95% CI, 1.23-4.50; AKI stages 2 and 3: HR 4.19, 95% CI, 2.22-7.92) and one-year mortality (AKI stage 1: HR 1.54, 95%CI, 1.00-2.37; AKI stages 2 and 3: HR 2.42, 95%CI, 1.50-3.90) and were more likely to develop new AKI (HR 1.60, 95%CI 1.15-2.23), incident CKD stage 3 and higher (39 (10.5%) vs 57 (7%), p = 0.037) and a major adverse kidney event (101 (19.6%) vs 119 (11.6%), p < 0.001) in the year following ED visit. Patients with CA-AKI visiting the ED have significantly worse outcomes than controls, including higher mortality, more frequent new AKI and progression to CKD stages 3 and higher. This calls for careful follow-up of these patients.