New Index for Multiple Chronic Conditions Predicts Functional Outcome in Ischemic Stroke

OBJECTIVETo determine whether a new index for Multiple Chronic Conditions (MCC) predicts post-stroke functional outcome (FO), we developed and internal validated the new MCC index in ischemic stroke patients. METHODSA prospective cohort of ischemic stroke patients (2008–2017) was interviewed at baseline and 90 days in the Brain Attack Surveillance in Corpus Christi Project. An average of 22 activities of daily living (ADL)/instrumental ADL (IADL) items measured the FO score (range 1–4) at 90 days. A FO score ≥3 (representing a lot of difficulty with ADL/IADLs) was considered unfavorable FO. A new index was developed using machine learning techniques to select and weight conditions and pre-stroke impairments. RESULTSPre-stroke modified Rankin Scale (mRS), age, congestive heart failure (CHF), weight loss, diabetes, other neurological disorders, and synergistic effects (dementia × age, CHF × renal failure, and pre-stroke mRS × prior stroke/TIA) were identified as important predictors in the MCC index. In the cross-validation dataset, the index alone explained 31% of the variability in the FO score, was well-calibrated (p = 0.41), predicted unfavorable FO well (area under the receiver operating characteristic curve, 0.81), and outperformed the modified Charlson Comorbidity Index in predicting the FO score and post-stroke mRS. CONCLUSIONSA new MCC index was developed and internally validated to improve the prediction of post-stroke FO. Novel predictors and synergistic interactions were identified. CLASSIFICATION OF EVIDENCEThis study provides Class II evidence that in patients with ischemic stroke an index for MCC predicts FO at 90 days