Effect of the interaction between hypertension and cerebral white matter changes on the progression of Alzheimer disease.

Background: Cerebrovascular pathologies and hypertension could play a vital role in Alzheimer disease (AD) progression. However, whether cerebrovascular pathologies and hypertension accelerate the AD progression through an independent or interaction effect is unknown. Objective: To investigate the effect of the interactions of cerebrovascular pathologies and hypertension on AD progression. Method: A retrospective longitudinal study was conducted to compare AD courses in patients with different severities of cerebral White Matter Changes (WMCs) in relation to hypertension. Annual comprehensive psychometrics were performed. WMCs were rated using a rating scale for Age-related WMCs (ARWMC). Results: In total, 278 patients with sporadic AD were enrolled in this study. The mean age of the patients was 76.6 +/- 7.4 years, and 166 patients had hypertension. Among AD patients with hypertension, those with deterioration in clinical dementia rating-sum of box (CDR-SB) and CDR had significantly severe baseline ARWMC scales in total (CDR-SB: 5.8 vs. 3.6, adjusted P = 0.04; CDR: 6.4 vs. 4.4, adjusted P = 0.04) and frontal area (CDR-SB: 2.4 vs. 1.2, adjusted P = 0.01; CDR: 2.4 vs. 1.7, adjusted P < 0.01) compared with those with no deterioration in psychometrics after adjustment for confounders. By contrast, among AD patients without hypertension, no significant differences in ARWMC scales were observed between patients with and without deterioration. Conclusion: The effect of cerebrovascular pathologies on AD progression between those with and without hypertension might differ. An interaction but not independent effect of hypertension and WMCs on the progression of AD is possible.