Impact of acute kidney injury during hospitalization on clinical outcomes after stroke

Abstract

Background: Acute kidney injury (AKI) is a frequent complication in hospitalized patients and has been associated with worse clinical outcomes. However, its impact during hospitalization in patients with stroke remains insufficiently characterized. Objective: To evaluate the impact of acute kidney injury during hospitalization on clinical outcomes in patients admitted with stroke. Methods: This observational cohort study included patients hospitalized for stroke in a regional referral center. Patients with insufficient data to define acute kidney injury were excluded. AKI was defined as an increase in serum creatinine ≥0.3 mg/dL within 48 hours, an increase to ≥1.5 times baseline within 7 days, or serum creatinine ≥4.0 mg/dL. A total of 764 patients were included in the analysis. Multivariable logistic regression models were used to evaluate associations between AKI and clinical outcomes, adjusted for age, sex, stroke severity at admission (NIHSS), and thrombolysis. Patients with prior chronic kidney disease were excluded from adjusted analyses. Outcomes included 90-day functional independence, 90-day mortality, and in-hospital delirium and infection. Statistical significance was defined as p<0.05. Results: A total of 764 patients were analyzed, of whom 302 (39.5%) developed AKI during hospitalization. In adjusted analyses, AKI was associated with lower odds of functional independence at 90 days (aOR 0.54; 95% CI 0.37–0.78; p=0.001) and higher 90-day mortality (aOR 2.64; 95% CI 1.35–5.16; p=0.005). Additionally, AKI was associated with increased odds of in-hospital delirium (aOR 2.17; 95% CI 1.48–3.18; p<0.001) and infection (aOR 3.48; 95% CI 2.49–4.86; p<0.001). In univariate analyses, AKI was not associated with age, sex, baseline NIHSS, or thrombolysis. Conclusion: AKI during hospitalization is associated with worse clinical outcomes after stroke, including reduced functional independence, higher mortality, and increased occurrence of delirium and infection, supporting its role as an important prognostic marker in this population.