Impact of coronary heart disease on cognitive decline in Alzheimer's disease: A prospective longitudinal cohort study in primary care

Abstract

Background Arteriosclerotic disorders increase the risk of dementia. As they have common causes and risk factors, coronary heart disease (CHD) could influence the course of dementia. Aim To determine whether CHD increases the speed of cognitive decline in Alzheimer's disease, and to discuss the potential for secondary cardiovascular prevention to modify this decline. Design and setting Prospective multicentre cohort study in general practices in six cities in Germany. Method Participants were patients with probable mildto- moderate Alzheimer's dementia or mixed dementia (n = 118; mean age 85.6 [±3.4] years, range 80-96 years). The authors assessed the presence of CHD according to the family physicians' diagnosis. Cognitive performance was measured during home visits for up to 3 years in intervals of 6 months, using Mini Mental State Examination (MMSE) and Clinical Dementia Rating Sum of Boxes (CDR-SoB). The authors also recorded whether patients died in the observation period. Results At baseline, 65 patients (55%) had CHD and/ or a heart condition following a myocardial infarction. The presence of CHD accelerated cognitive decline (MMSE, P<0.05) by about 66%, and reduced cognitive-functional ability (CDRSoB, P<0.05) by about 83%, but had no impact on survival. Conclusion The study shows that CHD has a significant influence on cognitive decline in older patients with late-onset dementia. The dementia process might therefore be positively influenced by cardiovascular prevention, and this possible effect should be further investigated.