Abstract / Summary
Abstract Background To evaluate associations of admission blood urea nitrogen with poor 90-day and 1-year functional outcomes after intravenous thrombolysis for acute ischemic stroke and assess multivariable model performance. Methods This single-center retrospective cohort included 375 eligible treatment records of acute ischemic stroke treated with standard-dose intravenous recombinant tissue plasminogen activator from January 2018 to January 2023. Modified Rankin Scale outcomes at 90 days and 1 year were classified as favorable (≤ 2) or poor (> 2). Baseline variables with < 15% missingness underwent MissForest imputation. LASSO-selected variables entered multivariable logistic regression models evaluated by 1000 bootstrap resamples, receiver operating characteristic, calibration, and decision curves. Results At 90 days, 207 (55.2%) had a favorable outcome and 168 (44.8%) a poor outcome; at 1 year, 242 (64.5%) and 133 (35.5%) had favorable and poor outcomes, respectively. In the 90-day model, age (OR = 1.04, 95% CI: 1.01–1.07, P = 0.002), admission NIHSS score (OR = 1.12, 95% CI: 1.08–1.17, P < 0.001), platelet distribution width (OR = 1.15, 95% CI: 1.02–1.28, P = 0.017), and blood urea nitrogen (OR = 1.42, 95% CI: 1.20–1.69, P < 0.001) were independently associated with poor outcome. The combined model, including smoking, had an AUC of 0.840 (95% CI: 0.800–0.880), versus 0.684 (95% CI: 0.630–0.738) for blood urea nitrogen alone. In the 1-year model, age (OR = 1.05, 95% CI: 1.02–1.08, P = 0.001), admission NIHSS score (OR = 1.12, 95% CI: 1.08–1.16, P < 0.001), and blood urea nitrogen (OR = 1.15, 95% CI: 1.03–1.29, P = 0.015) were independently associated with poor outcome. The combined model had an AUC of 0.818 (95% CI: 0.773–0.864), versus 0.633 (95% CI: 0.573–0.693) for blood urea nitrogen alone. Conclusions Higher admission blood urea nitrogen was associated with poor functional outcomes at both time points; age and admission NIHSS score were associated with both outcomes, whereas platelet distribution width was associated only with the 90-day outcome. The combined models had numerically higher AUCs than blood urea nitrogen alone in the study sample, but their clinical applicability requires external validation.