Outcomes of Community-Acquired Acute Kidney Injury: A Cohort Study of US Veterans.

BACKGROUND

Community-acquired acute kidney injury (CA-AKI) occurs outside of the hospital and is the most common form of AKI. CA-AKI is not well understood, which hinders efforts to prevent, identify, and manage CA-AKI.

OBJECTIVE

Examine 30-day outcomes following CA-AKI using national administrative and lab data from the Veterans Health Administration (VA).

RESEARCH DESIGN

Retrospective cohort study.

SUBJECTS

VA primary care patients with recorded outpatient serum creatinine (SCr) with observed CA-AKI (cases) and a standardized mortality ratio propensity-weighted 5% comparator sample without observed CA-AKI in 2013-2017.

MEASURES

CA-AKI was defined as a ≥1.5-fold relative increase in outpatient SCr or inpatient SCr (≤24 h from admission) from a reference outpatient SCr ≤12 months prior. Outcomes were 30-day mortality and hospitalization and were assessed in separate weighted Cox regression models.

RESULTS

Among 220,777 CA-AKI events and 492,539 comparators without observed CA-AKI, CA-AKI was associated with a higher risk of 30-day all-cause mortality [hazard ratio (HR)=4.17, 95% CI: 3.74, 4.63] and hospitalization (HR=1.82, 95% CI: 1.74, 1.90) versus comparator. Risks increased with severity (mortality HR=3.02, 7.67, and 12.22 for AKI stages 1-3, respectively). Outpatient CA-AKI was associated with a high risk of mortality (HR=2.04, 95% CI: 1.83, 2.28) and even higher for inpatient CA-AKI, present [≤24 h from admission (HR=11.32, 95% CI: 10.16, 12.61)].

CONCLUSIONS

In a national cohort of Veterans, CA-AKI was associated with a 2-fold increased risk of hospitalization and a 3-11-fold risk of mortality. Improving identification and management is critical to mitigate adverse outcomes of CA-AKI.