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.
RCT Entities:
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.
Authors: B A in t' Veld; A Ruitenberg; A Hofman; L J Launer; C M van Duijn; T Stijnen; M M Breteler; B H Stricker Journal: N Engl J Med Date: 2001-11-22 Impact factor: 91.245
Authors: Edo Richard; Esther Van den Heuvel; Eric P Moll van Charante; Lenny Achthoven; Marinus Vermeulen; Patrick J Bindels; Willem A Van Gool Journal: Alzheimer Dis Assoc Disord Date: 2009 Jul-Sep Impact factor: 2.703
Authors: Niels D Prins; Ewoud J van Dijk; Tom den Heijer; Sarah E Vermeer; Peter J Koudstaal; Matthijs Oudkerk; Albert Hofman; Monique M B Breteler Journal: Arch Neurol Date: 2004-10