Orthostatic Blood Pressure Behavior in People with Mild Cognitive Impairment Predicts Conversion to Dementia

Abstract

OBJECTIVES: To compare the patterns of blood pressure (BP) behavior during orthostasis in individuals with mild cognitive impairment (MCI) with those of controls and to investigate whether orthostatic BP behavior differs between individuals with MCI who convert to dementia and those who do not. DESIGN: Longitudinal study with 3 years of follow-up. SETTING: Memory clinic in Dublin, Ireland, between 2007 and 2012. PARTICIPANTS: Community-dwelling individuals with MCI (n = 150) and controls (n = 75). MEASUREMENTS: Orthostatic BP was examined using the active standing test with a beat-to-beat continuous BP monitoring device in addition to neuropsychological testing. Hazard ratios (HRs) from parametric survival models were used to determine whether conversion to dementia was independently associated with baseline orthostatic BP variables. RESULTS: Individuals with MCI were more likely than controls to have a systolic BP (SBP) deficit of greater than 30% 30 seconds after standing (P = .01). Thirty percent of participants with MCI (n = 43) converted to dementia within the 3-year follow-up period. Individuals with MCI with a SBP deficit greater than 30% 30 seconds after standing were twice as likely to convert to dementia as those without the deficit (HR = 2.77, 95% confidence interval = 1.02-7.50). CONCLUSION: Human beings have evolved an elaborate neurological control system to maintain cerebral perfusion during orthostatic challenge. In people with MCI, this response is impaired and renders them twice as likely to convert to dementia.