Accurate Prediction of Persistent Upper Extremity Impairment in Patients with Ischemic Stroke.

Abstract Objective To develop a simple and effective risk score for predicting which stroke patients will have persistent impairment of upper extremity motor function at 90 days. Design Post-hoc analysis of clinical trial patients hospitalized with acute ischemic stroke who were followed for 90 days to determine functional outcome. Setting Patient were hospitalized at facilities across the United States. Participants We created a harmonized cohort of individual patients from the NINDS tPA, ALIAS part 2, IMS-III, DEFUSE 3, and FAST-MAG trials. We split the cohort into balanced derivation and validation samples. Interventions Not applicable. Main Outcome Measures The primary outcome was persistent arm impairment, defined as an NIHSS arm domain score of 2-4 at 90 days in patients who had a 24-hour NIHSS arm score ≥1. We used LASSO regression to determine the elements of the Persistent UPPer extremity Impairment (PUPPI) index, which we validated as a predictive tool. Results We included 1,653 patients (827 derivation and 826 validation), of whom 803 (48.6%) had persistent arm impairment. The PUPPI index gives one point each for age ≥55 years and NIHSS values of worse arm=4, worse leg>2, facial palsy=3, and total NIHSS ≥10. The optimal cutpoint for the PUPPI index was ≥3, at which the area under the curve was >0.75 for the derivation and validation cohorts and when using NIHSS values from either 24 hours or in a subacute/discharge time window. Results were similar across different levels of stroke severity. Conclusion The PUPPI index uses readily available information to accurately predict persistent upper extremity motor impairment at 90 days post-stroke. The PUPPI index can be administered in minutes and could be used as inclusion criterion in recovery-related clinical trials or, with additional development, as a prognostic tool for patients, caregivers, and clinicians.