Evolution of blood pressure in patients with Alzheimer's disease: a one year survey of a French Cohort (REAL.FR).

OBJECTIVES: To determine the evolution of blood pressure in patients with moderate Alzheimer's disease among a one year longitudinal survey and to evaluate the relationship between blood pressure and cognitive functions.

METHODS: In 327 subjects selected from the French research program on Alzheimer's disease (REAL.FR), systolic and diastolic blood pressure (SBP, DBP) were measured at the time of inclusion (M0), after 6 months (M6) and after 12 months (M12). All subjects were assessed to determine both cognitive functions and capabilities in the activities of daily living using validated cognitive scales [Mini Mental State Examination (MMSE), Alzheimer's Disease Assessment Scale--Cognitive part (ADAS-Cog), Instrumental Activities of Daily Living (IADL), Activities of Daily Living (ADL), Clinical Dementia Rating (CDR)], at M0, M6, M12.

RESULTS: In this population of patients with moderate Alzheimer's disease, mean age was 78 +/- 7 years and 242 subjects were females (74%). After adjustment for age, gender, body mass index (BMI) and antihypertensive therapy, a significant decrease of blood pressure was observed between M0 and M12, for SBP (139.1 +/- 18 to 136.5 +/- 17 mmHg, p < 0.05) and DBP, (77.6 +/- 12 to 75.8 +/- 10 mmHg , p < 0.05). Demented subjects with the worst cognitive impairment at baseline (tertile1 MMSE, tertile 3 ADAS-Cog, ADL scores between 0 and 4, CDR scores between 10 to 18) showed a larger decrease in SBP and DBP after 12 months. The worst impairment in dementia at baseline was associated with the highest SBP decrease between M0 and M12 (delta SBP tertile 1 MMSE vs tertile 3 MMSE = -5.9 vs + 1.0 mmHg , p < 0.05; Delta SBP tertile 3 ADAS-Cog vs tertile 1 ADAS-Cog = - 5.98 vs + 2.98 mmHg, p < 0.05, Delta SBP ADL 0-4 vs ADL -6 = - 8.7 vs -1.5 mmHg, p < 0.05, delta SBP CDR 10-18 vs CDR 0.5-9.5 = - 6.9 vs -1.7 mmHg, p < 0.05). All these results persisted after adjustment for age, gender and the antihypertensive therapy. Baseline SBP [OR 95% CI = 1.05 (1.02-1.08), BMI [OR 95% CI = 0.88 (0.81-0.95)], ADL score [OR 95% CI = 0.42 (0.22-0.81)] and ADAS-Cog score [OR 95% CI = 1.07 (1.01-1.14)] were significantly associated with the decrease of blood pressure after one year of follow up, independently of age, gender and antihypertensive therapy. In contrast, patients with larger blood pressure decrease (over 10 mmHg reduction of SBP and/or 5 mmHg of DBP) did not demonstrate a more significant worsening of dementia at 12 months in the different scales used.

CONCLUSIONS: This study indicates a significant decrease in blood pressure in patients with Alzheimer's disease after one year of follow up, independently of age, gender, BMI and antihypertensive therapy. The largest decrease in blood pressure was observed in patients with the most severe impairment in dementia at baseline, suggesting that blood pressure decrease seems to be mainly a secondary phenomenon in Alzheimer's disorders.