O4‐03‐04: PROFILE OF AND RISK FACTORS FOR POST‐STROKE COGNITIVE IMPAIRMENT IN DIVERSE ETHNO‐REGIONAL GROUPS

Objective To address the variability in prevalence estimates and inconsistencies in potential risk factors for poststroke cognitive impairment (PSCI) using a standardized approach and individual participant data (IPD) from international cohorts in the Stroke and Cognition Consortium (STROKOG) consortium. Methods We harmonized data from 13 studies based in 8 countries. Neuropsychological test scores 2 to 6 months after stroke or TIA and appropriate normative data were used to calculate standardized cognitive domain scores. Domain-specific impairment was based on percentile cutoffs from normative groups, and associations between domain scores and risk factors were examined with 1-stage IPD meta-analysis. Results In a combined sample of 3,146 participants admitted to hospital for stroke (97%) or TIA (3%), 44% were impaired in global cognition and 30% to 35% were impaired in individual domains 2 to 6 months after the index event. Diabetes mellitus and a history of stroke were strongly associated with poorer cognitive function after covariate adjustments; hypertension, smoking, and atrial fibrillation had weaker domain-specific associations. While there were no significant differences in domain impairment among ethnoracial groups, some interethnic differences were found in the effects of risk factors on cognition. Conclusions This study confirms the high prevalence of PSCI in diverse populations, highlights common risk factors, in particular diabetes mellitus, and points to ethnoracial differences that warrant attention in the development of prevention strategies. From the Centre for Healthy Brain Ageing (J.W.L., J.D.C., R.J.C., H.B., D.M.L., N.A.K., P.S.S.), University of New South Wales, Sydney, Australia; Department of Neurology and Laboratory of Functional Neurosciences (O.G., M.B., M.R.), University Hospital of Amiens, France; Clinical Neurosciences (H.J., S.M., T.E.), Neurology, University of Helsinki and Helsinki University Hospital, Finland; Department of Internal Medicine (S.M.), Gerontology and Geriatrics Section, and Department of Cardiology (J.W.J.), Leiden University Medical Center, the Netherlands; Department of Neurology (S.M., B.S.), Feinberg School of Medicine, Northwestern University, Chicago, IL; Department of Neurology (H.-J.B.), Seoul National University School of Medicine, Seoul National University Bundang Hospital, Seongnam; Department of Neurology (J.-S.L., B.-C.L.), Hallym University Sacred Heart Hospital, Anyang, Republic of Korea; Department of Psychiatry and Neuropsychology (S.K., E.D.), School for Mental Health and Neuroscience, Alzheimer Center Limburg, Maastricht University; Department of Neurology (J.S.), Cardiovascular Research Institute Maastricht,MaastrichtUniversityMedicalCenter, theNetherlands;MemoryAgingandCognitionCentre (C.C., X.X., E.J.C.),DepartmentofPharmacology, YongLooLinSchoolofMedicine,National University of Singapore; Centre for Population Health Sciences (X.X.), Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore; Neuroscience and Ageing Research Unit (R.O.A., A.O.), Institute for Advanced Medical Research and Training, and Department of Medicine (R.O.A.), College of Medicine, University of Ibadan, Nigeria; Institute of Neuroscience (R.N.K.), Newcastle University, Newcastle Upon Tyne, UK; Peninsula Clinical School (V.K.S., C.M.), Central Clinical School, Monash University; Department of Aged Care (C.M.), Alfred Health, Melbourne, Australia; National Neuroscience Institute (N.K., R.J.C.); Duke-NUSMedical School (N.K.), Singapore; Dementia Collaborative ResearchCentre (H.B., P.S.S.), University of NewSouthWales, Sydney, Australia; and University of Lille (R.B., S.B., H.H.), Inserm, CHU Lille, U1171-Degenerative & Vascular Cognitive Disorders, France. Go to Neurology.org/N for full disclosures. Funding information and disclosures deemed relevant by the authors, if any, are provided at the end of the article. STROKOG collaboration coinvestigators are listed in Appendix 2 at the end of the article. This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND), which permits downloading and sharing the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal. Copyright © 2019 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology. e2257 While poststroke cognitive impairment (PSCI) is mild in many stroke survivors, numerous studies have reported a prevalence of dementia in poststroke cases that varies from 7.4% in a population-based study of first stroke to 41.3% in hospital-based cases of recurrent stroke. The prevalence may differ by geographic region, diagnostic criteria, and methods of assessment. Because the severity of cognitive impairment in poststroke patients is on a continuum, however, it is arguably more meaningful to use a standardized continuous measure to examine cognitive impairment rather than the diagnosis of dementia. Because of the heterogeneity of stroke and its effects on cerebral function, the cognitive profile of poststroke dementia is understandably complex. There is evidence that some cognitive domains, in particular complex attention, working memory, and frontal executive function, are affected early in vascular dementia. Poststroke dementia, however, is also associated with language and visuospatial dysfunction, even though individuals with severe language impairment are often excluded from detailed investigations. In addition, studies of cognitive profile have largely been conducted in white, non-Hispanic populations, and it is uncertain whether the same pattern is seen in Asian and African populations. The clinical determinants of PSCI remain incompletely understood. While older age and low levels of education have consistently emerged as risk factors, various other putative risk factors have been inconsistently reported, including risk factors for cerebrovascular disease (e.g., hypertension, diabetes mellitus, atrial fibrillation [AF], smoking), prior pathology (e.g., previous stroke, Alzheimer disease), APOE genotype, stroke features, and lesion characteristics. The variability of the findings has prevented a consensus from being reached on the most relevant factors in predicting the development of poststroke dementia. The Stroke and Cognition Consortium (STROKOG), an international consortium of studies of cognitive decline and dementia after stroke or TIA, offers an opportunity to address the inconsistencies in prevalence estimates and potential risk factors for PSCI. This article presents a comprehensive profile of the cognitive performance of patients 2 to 6 months after stroke or TIA and explores the associations between a variety of risk factors and impairment in cognitive function. We hypothesized that the prevalence of Glossary AF = atrial fibrillation; CHF = congestive heart failure; DSM-IV = Diagnostic and Statistical Manual of Mental Disorders, 4th edition; IPD = individual participant data; MI = myocardial infarction; NEMESIS = North East Melbourne Stroke Incidence Study; PROSPER = Prospective Study of Pravastatin in the Elderly at Risk; PSCI = poststroke cognitive impairment; SAM = Helsinki Stroke Aging Memory Study; STROKDEM = Study of Factors Influencing Post-Stroke Dementia; STROKOG = Stroke and Cognition Consortium. e2258 Neurology | Volume 93, Number 24 | December 10, 2019 Neurology.org/N PSCI will be high across different geographical regions but will vary across different ethnoracial groups. We also hypothesized that PSCI affects different cognitive domains equally and that vascular risk factors for stroke are also risk factors for PSCI independently of the occurrence of stroke.