Development and validation of domain-specific clinical prediction models of post-stroke cognitive impairment

Background and ObjectivesPost-stroke cognitive impairment (PSCI) is highly prevalent across multiple cognitive domains. Individualised PSCI prognosis has mainly been researched using outcomes not developed specifically for stroke (i.e., dementia risk). Further, existing models often use predictors not routinely available in electronic health records. Here, we develop and externally validate clinical prediction models for overall PSCI using a stroke-specific cognitive outcome using acute cognition and data routinely collected as part of stroke care. MethodsN=430 stroke survivors completed the Oxford Cognitive Screen (OCS) in acute care and at 6-month follow-up (binarized outcome; impaired vs unimpaired). Logistic regression models were fitted comprising both mandatory clinically-relevant (age, sex, stroke severity, education, stroke hemisphere, acute PSCI) and data-driven (acute mood difficulties, length of stay in acute care, multimorbidity) predictors using backward elimination (p < 0.10) on multiply imputed data. Internal validation used bootstrapping to obtain optimism-adjusted performance estimates. External validation used the optimism-adjusted C-Slope as a uniform shrinkage factor. ResultsThe overall PSCI model demonstrated good optimism-adjusted performance (C-Statistic=0.76 [95% CI=0.71-0.80]). In external validation, the overall PSCI model was comparable to development data (C-Statistic=0.74 [95% CI=0.67-0.79]). PSCI model performance did not vary by sex, but performed best in adults <60 years old (C-Statistic=0.76) with moderate-severe acute PSCI (C-Statistic=0.72). We further explored modelling of DiscussionPrediction models of stroke-specific cognition have the potential to offer more meaningful PSCI prognoses, including domain-specific cognitive recovery, compared to existing models focused on domain-general decline. The present model shows promise of generalisability with an initial good external validation performance of the PSCI model in a different stroke severity cohort. Future recalibration of domain-specific models would be beneficial to provide additional detailed predictions.