Atrial Fibrillation: Major Risk for Cognitive Decline
Atrial Fibrillation: Major Risk for Cognitive Decline
Numerous studies have been conducted examining the association between AF and cognitive impairment, with diverse populations ranging from case series of acute stroke inpatients to community-dwelling population-based longitudinal studies. Because of the heterogeneity of populations, methods, and analysis of the literature, 4 reviewsand 3 meta-analyses (Table I) were reviewed, whereas prospective cohort and cross-sectional studies were excluded. In general, studies support a positive association, with relative risk ranging from 1.4 to 2.8, depending on the presence of stroke. Significant heterogeneity was present, precluding a formal meta-analysis in several reviews. Two meta-analyses included studies of patients with strokes, finding significant heterogeneity among studies of broader patients and little heterogeneity when studies were limited to stroke patients or dementia. Only 1 meta-analysis examined studies of patients with normal cognitive function at baseline with no history of stroke, but the outcome examined was incident dementia and not cognitive decline. Of note, the criteria for the diagnosis and classification of AF were noted by many authors to be poor; 1 semisystematic review noted that 3 studies used a single electrocardiogram, software program, and diagnosis code as the basis for AF diagnosis. New technologic advances with implantable loop recorders having higher sensitivity and specificity may improve the diagnosis and classification in future AF studies.
Epidemiology
Numerous studies have been conducted examining the association between AF and cognitive impairment, with diverse populations ranging from case series of acute stroke inpatients to community-dwelling population-based longitudinal studies. Because of the heterogeneity of populations, methods, and analysis of the literature, 4 reviewsand 3 meta-analyses (Table I) were reviewed, whereas prospective cohort and cross-sectional studies were excluded. In general, studies support a positive association, with relative risk ranging from 1.4 to 2.8, depending on the presence of stroke. Significant heterogeneity was present, precluding a formal meta-analysis in several reviews. Two meta-analyses included studies of patients with strokes, finding significant heterogeneity among studies of broader patients and little heterogeneity when studies were limited to stroke patients or dementia. Only 1 meta-analysis examined studies of patients with normal cognitive function at baseline with no history of stroke, but the outcome examined was incident dementia and not cognitive decline. Of note, the criteria for the diagnosis and classification of AF were noted by many authors to be poor; 1 semisystematic review noted that 3 studies used a single electrocardiogram, software program, and diagnosis code as the basis for AF diagnosis. New technologic advances with implantable loop recorders having higher sensitivity and specificity may improve the diagnosis and classification in future AF studies.
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