Acute kidney injury is associated with increased hospital mortality after stroke

Abstract

Background: Acute kidney injury (AKI) is common and is associated with poor clinical outcomes. Information about the incidence of AKI and its effect on stroke outcomes is limited.

Methods: Data were analyzed from a registry of subjects with ischemic stroke and intracerebral hemorrhage (ICH) hospitalized at a single academic medical center. Admission creatinine was considered to be the baseline. AKI was defined as a creatinine increase during hospitalization of 0.3 mg/dL or a percentage increase of at least 50% from baseline. Multivariate logistic regression models were created for both stroke types, with hospital mortality as the outcome. Covariates included gender, race, age, admission creatinine, National Institutes of Health Stroke Scale score at admission, the performance of a contrast-enhanced computed tomographic scan of the head and neck, and medical comorbidities.

Results: There were 528 cases of ischemic stroke with 70 deaths (13%), and 829 cases of ICH with 268 deaths (32%). The mean age was 64 years; 56% of patients were men and 71% were white. AKI complicated 14% of ischemic stroke and 21% of ICH hospitalizations. In multivariate analysis stratified by stroke type, AKI was associated with increased hospital mortality from ischemic stroke (odds ratio [OR] 3.08; 95% confidence interval [CI] 1.49-6.35) but not ICH (OR 0.82; 95% CI 0.50-1.35), except for those surviving at least 2 days (OR 2.11; 95% CI 1.18-3.77).

Conclusions: AKI occurs frequently after stroke and is associated with increased hospital mortality. Additional studies are needed to establish if the association is causal and if measures to prevent AKI would result in decreased mortality.

Keywords: Acute kidney injury; intracerebral hemorrhage; ischemic stroke; kidney disease.