The effect of blood pressure control on cognitive function (the focus study)

Abstract

Dementia affects hundreds of thousands of patients with potential to affect millions as the population ages. Vascular causes represent 40% of patients with dementia. We sought to determine whether patients with mild to moderate hypertension, multiple white matter infarctions and clinical evidence of cognitive impairment would improve their cognitive status when treated to recommended blood pressure goals. We performed a PROBE (prospective, randomized, open-label, end-point blinded) design trial of 66 patients; 24 females, 42 males. Subjects were between the ages of 65-80, with previously untreated or poorly controlled hypertension (systolic blood pressure of 140-180 mm Hg and/or diastolic blood pressure of 90-110 mm Hg). All had multiple white matter infarctions by magnetic resonance imaging (MRI), cognitive dysfunction determined by psychometric testing and absence of stroke. Subjects were randomly assigned to felodipine or enalapril and underwent treatment for 24 weeks with doses titrated as necessary to achieve goal blood pressure of <140/90 mm Hg. There was no significant difference between the two groups with regard to age, sex, education or marital status. A battery of neuropsychological tests assessing attention and mental control, information processing speed, verbal memory, visuo-spatial skills, executive skills, and motor functioning, was performed at randomization (following a two placebo week washout period), 12 weeks and 24 weeks. Both groups showed statistically significant improvement in overall cognitive function at 12 weeks without regard to treatment arm (p<0.001). There was significant improvement within the specific cognitive domains of information processing (p<0.001), visuo-spatial skills (p<0.001), executive skills (p=0.004), and motor functioning (p<0.001). Improvement in overall cognitive function at 24 weeks remained significantly better than baseline (p=0.0056) but not different than that seen at 12 weeks. We believe this is the first study to suggest that rigorous control of blood pressure to currently recommended treatment goals of <140/90 mm Hg is associated with overall, as well as specific domain cognitive improvement in hypertensive patients with impaired cognitive function. Grant/Research Support: Astra-Zeneca, Merck Speakers Bureau: Astra-Zeneca, Abbott