Long-Term Effects of Secondary Prevention on Cognitive Function in Stroke Patients
What is the effect of secondary prevention of vascular events on cognitive function after stroke?
Data were collected between 1995 and 2011 (n = 4,413) as part of a prospective population-based stroke register that was set up in January 1995, and records all first-ever strokes in patients of all ages for an inner area of South London, including 22 electoral wards in Lambeth and Southwark. The total source population included 271,817 individuals; their self-reported race was as follows: 63% white, 28% black (9% black Caribbean, 15% black African, and 4% black other), and 9% other. Modified Poisson regression models were constructed to adjust for cognitive function status at 3 months, demographic and socioeconomic characteristics, case mix, stroke subtype, vascular risk factors, disability, and stroke recurrence.
The community-based South London Stroke Register covers an inner-city multiethnic source population of 271,817 inhabitants, of which 4,413 patients had their first-ever stroke between January 1, 1995, and December 31, 2011, of whom 1,137 (26%) were dead within 3 months, 689 (16%) were not eligible because of late registration or because their date of follow-up was not reached, and 575 (13%) were unable to undergo a cognitive assessment because of a severe verbal, visual, or hearing impairment. Of the 2,012 remaining subjects, 1,682 stroke survivors were able to undergo a cognitive assessment at 3 months, 1,448 at 1 year, 684 at 5 years, and 200 at 10 years. Among patients with ischemic strokes without a history of atrial fibrillation (AF), there was a reduced risk of cognitive impairment associated with the use of different prevention treatments: 1) antihypertensive medications (relative risk [RR], 0.7 [95% confidence interval (CI), 0.57-0.82] for diuretics; RR, 0.8 [95% CI, 0.64-0.98] for angiotensin-converting enzyme inhibitors; and RR, 0.7 [95% CI, 0.55-0.81] for their combination), 2) a combination of aspirin and dipyridamole (RR, 0.8 [95% CI, 0.68-1.01]), and 3) statin (RR, 0.9 [95% CI, 0.76-1.06]) when clinically indicated. Protective effects against cognitive impairment were also observed in patients on the combination of antihypertensive medications, antithrombotic agents, and lipid-lowering drugs (RR, 0.55 [95% CI, 0.40-0.77]). No significant associations were noted between post-stroke cognitive impairment and antihypertensive medications among hemorrhagic stroke patients.
The investigators concluded that appropriate vascular risk management was associated with a long-term reduced risk of cognitive impairment. Focus on optimal preventive drug therapy of vascular risk factors and management should be supported.
Although limitations exist, in particular the inability to perform cognitive testing over time in many participants, these data support current recommendations for secondary preventions. Additional data, which includes lifestyle therapies, are warranted.
Keywords: Follow-Up Studies, Caribbean Region, European Continental Ancestry Group, Risk Factors, Fibrinolytic Agents, Cognition Disorders, Secondary Prevention, London, Cardiology, Dementia, Cardiovascular Diseases, African Continental Ancestry Group, Dipyridamole
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