Is prolonged delirium associated with worse functional outcomes after stroke?

Abstract

Background: Although the occurrence of delirium is known to negatively impact clinical outcomes, the influence of its duration on long-term functional recovery after stroke remains unclear. Objective: To evaluate the association between prolonged delirium and functional outcome in patients with stroke. Methods: This prospective cohort study was conducted from July 2023 to March 2026 and included patients aged ≥ 18 years admitted to an intensive care unit with a diagnosis of stroke. Delirium was assessed during hospitalization through the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU), and its duration was recorded in days. The primary endpoint was an unfavorable functional outcome at 90 days, defined as a modified Rankin Scale (mRS) score ≥ 3. To evaluate the independent association between delirium duration and outcome, a multivariable logistic regression analysis was performed. The model was adjusted for age, sex, educational level, diabetes mellitus, systemic arterial hypertension, dyslipidemia, atrial fibrillation, premorbid mRS, prior stroke, smoking status, alcohol use, stroke type (ischemic or hemorrhagic), fibrinolytic therapy, baseline National Institutes of Health Stroke Scale (NIHSS) score, and in-hospital infection. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were calculated. Model discrimination was assessed using the area under the receiver operating characteristic curve (AUC). Results: A total of 588 patients met the inclusion criteria. The mean age was 65.9 ± 12.8 years, and 49.3% were male. Most patients had ischemic stroke (93.7%), with a mean baseline NIHSS score of 8.5 ± 5.4. In the multivariable logistic regression analysis, prolonged delirium was independently associated with an increased odds of unfavorable functional outcome at 90 days (aOR 1.32 [95% CI 1.10–1.59], p = 0.003), indicating that each additional day of delirium increased the odds of poor functional outcome by 32%. Furthermore, prolonged delirium demonstrated excellent discrimination for predicting unfavorable functional outcome at 90 days (AUC 0.907 [95% CI 0.841–0.962], p < 0.001). Conclusion: Prolonged delirium was independently associated with unfavorable functional outcomes at 90 days after stroke, and demonstrated excellent discriminative performance. These findings suggest that not only the occurrence of delirium, but also its duration, plays a crucial role in its impact on functional outcomes after stroke.