Risks for impaired post-stroke cognitive function

In a printed posted to the medRxiv preprint archive this month, I found a chart review of patients with stroke to determine factors (other than the stroke itself) which could predict cognitive impairment following the stroke admission to hospital.
The paper used patients admitted to Massachusetts General Hospital as their cases for which to form a risk factor formula, and then validated the formula against cases in a sister Boston hospital, Brighamm and Women’s Hospital.
The results are quoted as a table below:

The results found were that older age was the biggest overall risk factor (weighted for example as 4 for > 65, 8 for > 85), followed by those weighted 2: insurance of Medicare (a proxy for age over 65), mobility problems, delirium, peripheral vascular disease, and depression. Other factors were rated only at a weight of 1: these included Medicaid(a proxy for low income), prior falls, Parkinson’s, kidney disease, weight loss, and nursing home placement from the acute hospital stay.
Indeed, it seems that the factors found more significant, such as age, gait status, depression, delirium, vascular disease, are actually all also known from other, prospective studies to be risk factors for dementia in the general population, even in those without any stroke.
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ABSTRACT
Predicting post-stroke cognitive impairment using electronic health record data
Jeffrey M. Ashburner, PhD, MPH1,2; Yuchiao Chang, PhD1,2; Bianca Porneala, MS1; Sanjula D. Singh, MD, PhD3; Nirupama Yechoor, MD, MSc3; Jonathan M. Rosand, MD, MSc3; Daniel E. Singer, MD1,2; Christopher D. Anderson, MD, MMSc4; Steven J. Atlas, MD, MPH
medRxiv preprint: https://doi.org/10.1101/2024.02.02.24302240
Importance: Secondary prevention interventions to reduce post-stroke cognitive impairment (PSCI) can be aided by the early identification of high-risk individuals who would benefit from risk factor modification.
Objective: To develop and evaluate a predictive model to identify patients at increased risk of PSCI over 5 years using data easily accessible from electronic health records.
Design: Cohort study with patients enrolled between 2003-2016 with follow-up through 2022. Setting: Primary care practices affiliated with two academic medical centers.
Participants: Individuals 45 years or older, without prior stroke or prevalent cognitive impairment, with primary care visits and an incident ischemic stroke between 2003-2016 (development/internal validation cohort) or 2010-2022 (external validation cohort).
Exposures: Predictors of PSCI were ascertained from the electronic health record.
Main Outcome: The outcome was incident dementia/cognitive impairment within 5 years and beginning 3 months following stroke, ascertained using ICD-9/10 codes. For model variable selection, we considered potential predictors of PSCI and constructed 400 bootstrap samples with two-thirds of the model derivation sample. We ran 10-fold cross-validated Cox proportional hazards models using a least absolute shrinkage and selection operator (LASSO) penalty. Variables selected in >25% of samples were included. Results: The analysis included 332 incident diagnoses of PSCI in the development cohort (n=3,741), and 161 and 128 incident diagnoses in the internal (n=1,925) and external (n=2,237) validation cohorts. The c-statistic for predicting PSCI was 0.731 (95% CI: 0.694-0.768) in the internal validation cohort, and 0.724 (95% CI: 0.681-0.766) in the external validation cohort. A risk score based on the beta coefficients of predictors from the development cohort stratified patients into low (0-7 points), intermediate (8-11 points), and high (12-35 points) risk groups. The hazard ratios for incident PSCI were significantly different by risk categories in internal (High, HR: 6.2, 95% CI 4.1-9.3; Intermediate, HR 2.7, 95% CI: 1.8-4.1) and external (High, HR: 6.1, 95% CI: 3.9-9.6; Intermediate, HR 2.8, 95% CI: 1.9-4.3) validation cohorts.
Conclusions and Relevance: Five-year risk of PSCI can be accurately predicted using routinely collected data. Model output can be used to risk stratify and identify individuals at increased risk for PSCI for preventive efforts.
Key Words: post-stroke cognitive impairment, risk stratification, risk prediction