Differences in characteristics and outcomes between community- and hospital-acquired acute kidney injury: A systematic review and meta-analysis

Introduction: No comprehensive review has examined the difference between community-acquired (CA) and hospital-acquired (HA) acute kidney injury (AKI) in terms of patient characteristics, inhospital mortality, and hospital stay length. Materials and methods: We conducted a systematic review and meta-analysis of observational studies, using MEDLINE, EMBASE, Web of Science, Google Scholar, and the Cochrane Library from their inceptions to April 10, 2016. Observational studies that (1) were published in peer-reviewed journals; (2) compared CA-AKI with HA-AKI, irrespective of the AKI definition during the same period; and (3) investigated in-hospital mortality and length of hospital stay were studied. Differences in the patients' baseline characteristics were analyzed, and a meta-analysis was conducted to compare the in-hospital mortality and length of hospital stay. Results: Eight eligible observational studies with 17,939 patients were included. The systematic review showed that patients with CA-AKI had a significantly higher rate of AKI stage 3 compared with those with HA-AKI. The meta-analysis revealed that patients with CA-AKI showed significantly lower in-hospital mortality (odds ratio (OR) = 2.79; Z = 8.22; 95% confidence interval (CI), 2.18 - 3.56; p < 0.001) and shorter length of hospital stay (OR = 2.55; Z = 5.81; 95% CI, 1.86 - 3.50; p < 0.001). Subanalyses of studies conducted in developing and developed countries showed that patients with CA-AKI had lower in-hospital mortality and shorter length of hospital stay. Jackknife sensitivity analyses confirmed the replicability of these findings (p < 0.001). Conclusion: The results indicate that significant differences exist in clinical phenotypes between CA- and HA-AKI, even when standardized diagnosis criteria are used.