[Isolated systolic hypertension and cognitive function in the aged. Experience of the Syst-Eur study]

To determinate cognitive status and its correlates in older patients with isolated systolic hypertension.

Syst-Eur is a double-blind placebo-controlled outcome trial conducted in European patients over 60 years of age with isolated systolic hypertension. Moreover, a side-project--the Vascular Dementia Project--is designed to assess cognitive functions and to follow-up their evolution to determine the influence of antihypertensive therapy on vascular dementia incidence. Cognitive functions were evaluated at entry with the MiniMental State Examination (MMSE) in 2250 patients included in Syst-Eur. Cognitive impairment was defined with a MMSE score < or = 23 and led to further evaluation. Baseline blood pressure (BP) was based on the average of six sitting blood pressure readings at three run-in visits 1 month apart. Statistical analysis used Spearman correlation.

The MMSE was analysed in 1374 women and 751 men whose mean age was 70 years (range: 60-100). The median level of education expressed as the age at which they stopped their education at school, was 15 years. Baseline blood pressure averaged 173 +/- 10/86 +/- 6 mmHg. Before randomisation in the trial, 899 (40%) patients had received antihypertensive therapy and 602 (27%) had experienced cardiovascular complications. The MMSE-scores ranged from 15 to 30 (median = 29). The maximal score of 30 was reached by 609 (30%) subjects. Among the 59 (3%) patients with a MMSE-score of 23 or less, 5 were considered to be demented according to the DSM IIIR criteria. The MMSE-scores decreased with advancing age in men (r = -0.16; p < 0.001) and women alike (r = -0.24; p < 0.001). In both men and women, they were positively correlated with the level of education (r = 0.30 and 0.32, respectively; p < 0.001). They were negatively correlated with systolic blood pressure (r = 0.10; p < 0.001) and slightly positively correlated with diastolic blood pressure (r = 0.05; p = 0.03). Previously treated patients or patients reporting cardiovascular complications at baseline had lower MMSE-scores than their non-treated counterparts or subjects without cardiovascular complications (median = 28 and 29, respectively, p < 0.003).

In a European cohort of 2225 patients over 60 years of age with isolated systolic hypertension, the level of cognitive functions evaluated with the MMSE decreases with advancing age or lesser educational level. It also decreases with higher systolic blood pressure or lower diastolic blood pressure. The influence of antihypertensive therapy on cognitive status will be prospectively evaluated in Syst-Eur Vascular Dementia Project.