Abstract
Objectives
Description of methodological issues in a trial designed to evaluate if a multi-component intervention aimed at vascular risk factors can prevent dementia.
Design, setting and participants
Multi-center, open, cluster-randomized controlled clinical trial (preDIVA) including 3535 non-demented subjects aged 70–78, executed in primary practice and coordinated from one academic hospital. General practices are randomized to standard care or intensive vascular care.
Intervention
Vascular care consists of 4-monthly visits to a practice nurse who monitors all cardiovascular risk factors. Hypertension, hypercholesterolemia, overweight, lack of physical exercise and diabetes are strictly controlled according to a protocol and treated in a way, tailored to the characteristics of individual participants.
Measurements
Primary outcomes are incident dementia and disability; secondary outcomes are mortality, vascular events (stroke, myocardial infarction, peripheral vascular disease), cognitive decline and depression.
Results
Between May 2006 and February 2009, 3535 subjects from 115 general practices have been included. The clusters have an average size of 31 (SD 22, range 2–114). 1658 Patients from 52 practices were randomized to the standard care condition and 1877 patients in 63 practices to the vascular care condition.
Discussion
When designing a cluster-randomized trial, clustering of patient data within GP practices leads to a loss of power. This should be adjusted for in the power calculation. Since intensive vascular care will probably lead to a reduction in cardiovascular mortality, the competing risks of mortality and dementia should be taken into account.
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References
Breteler MM. Vascular risk factors for Alzheimer’s disease: an epidemiologic perspective. Neurobiol Aging 2000;21:153–160.
Prins ND, van Dijk EJ, den HT et al. Cerebral white matter lesions and the risk of dementia. Arch Neurol 2004;61:1531–1534.
Schneider JA, Arvanitakis Z, Bang W, Bennett DA. Mixed brain pathologies account for most dementia cases in community-dwelling older persons. Neurology 2007;69:2197–2204.
Holman R, Lindeboom R, Vermeulen M, de Haan RJ. The AMC Linear Disability Score project in a population requiring residential care: psychometric properties. Health Qual Life Outcomes 2004;2:42.
Campbell MK, Elbourne DR, Altman DG. CONSORT statement: extension to cluster randomised trials. BMJ 2004;328:702–708.
Richard E, Van den Heuvel E, Moll van Charante EP et al. Prevention of dementia by intensive vascular care (PreDIVA): a cluster-randomized trial in progress. Alzheimer Dis Assoc Disord 2009;23:198–204.
Beiser A, D’Agostino RB, Sr., Seshadri S, Sullivan LM, Wolf PA. Computing estimates of incidence, including lifetime risk: Alzheimer’s disease in the Framingham Study. The Practical Incidence Estimators (PIE) macro. Stat Med 2000;19:1495–1522.
in t’ Veld BA, Ruitenberg A, Hofman A et al. Nonsteroidal antiinflammatory drugs and the risk of Alzheimer’s disease. N Engl J Med 2001;345:1515–1521.
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Richard, E., Ligthart, S.A., Moll van Charante, E.P. et al. Methodological issues in a cluster-randomized trial to prevent dementia by intensive vascular care. J Nutr Health Aging 14, 315–317 (2010). https://doi.org/10.1007/s12603-010-0072-3
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DOI: https://doi.org/10.1007/s12603-010-0072-3