A substudy protocol of the hypertension in the Very Elderly Trial assessing cognitive decline and dementia incidence (HYVET-COG) : An ongoing randomised, double-blind, placebo-controlled trial.

BACKGROUND AND OBJECTIVE: Randomised, controlled trials and population studies have suggested a link between hypertension and the development of dementia (vascular dementia and Alzheimer's disease) although the results are not conclusive. The very elderly are at highest risk for both hypertension and dementia but have been underrepresented in studies to date. The Hypertension in the Very Elderly Trial (HYVET), an international, randomised, double-blind, placebo-controlled trial of antihypertensive medication for those > or =80 years of age, is currently underway. The protocol for the assessment of cognitive decline and detection of incident dementia cases is described in this article. The objective of this protocol is to determine whether treatment of hypertension in this very elderly group affects the incidence of dementia and decline in cognitive function during the period of the HYVET trial. METHODS: Cognitive function in all HYVET trial participants is assessed at baseline and annually thereafter using the Mini-Mental State Examination (MMSE). An MMSE score that decreases more than three points per year or decreases to or =80 years of age with hypertension. The HYVET trial is placebo controlled and while investigating the cardiovascular effect of treatment also assesses cognitive function and quality of life in both the placebo and actively treated arms of the trial. The HYVET cognitive substudy trial (HYVET-COG) design has been successfully applied and the instruments chosen appear to be appropriate, valid and pragmatic. CONCLUSION: HYVET-COG provides the first opportunity to examine the effect of antihypertensive treatment on incident dementia in a high-risk very elderly population