Blood Pressure Variability in Alzheimer's Disease and Frontotemporal Dementia: The Effect on the Rate of Cognitive Decline

Background: The link between vascular disease and cognitive impairment is a matter of an ongoing debate, and different cardiovascular conditions have been found to be predictors of the clinical development and progression of cognitive dysfunction. Objective: To compare the influence of visit-to visit blood pressure (BP) variability on the rate of cognitive decline in Alzheimer's disease (AD) and frontotemporal dementia (FTD). Methods: The patients affected by AD and FTD consecutively admitted to our center from January 2007 to September 2012 were evaluated every three months for a one-year period. The BP mean and coefficient of variation as index of variability were obtained for both systolic and diastolic values. Progression of cognitive decline was investigated using the Mini-Mental State Examination administered at entry and at the end of the follow-up. Results: Two-hundred and forty-eight AD and eighty-one FTD patients were enrolled. Systolic and diastolic BP mean and variability were comparable between the two groups. Systolic BP variability (BPV) was associated with the rate of cognitive impairment in AD (B = 0.367, beta = 0.739, R-2 = 0.594, adjusted R-2 = 0.567; p < 0.001), but not in FTD patients; no relationship emerged between any other BP index and cognitive decline. Conclusion: The relationship between BPV and cognitive function is still not completely understood, and it may play different roles according to the types and stages of dementia. Fluctuations in systolic BP may contribute to the cognitive decline in AD patients and may represent a neglected therapeutic target.