Is the cognitive function of older patients affected by antihypertensive treatment? Results from 54 months of the Medical Research Council's trial of hypertension in older adults.

OBJECTIVE

To establish whether initiation of treatment with diuretic or beta blocker is associated over 54 months with change in cognitive function.

DESIGN

A cognitive substudy, nested within a randomised, placebo controlled, single blind trial.

SETTING

226 general practices from the Medical Research Council's general practice research framework.

SUBJECTS

A subset of 2584 subjects sequentially recruited from among the 4396 participants aged 65-74 in the trial of treatment of hypertension in older adults. The 4396 subjects were randomised to receive diuretic, beta blocker, or placebo. Subjects had mean systolic pressures of 160-209 mm Hg and mean diastolic pressures <115 mm Hg during an eight week run in.

OUTCOME MEASURES

The rate of change in paired associate learning test (PALT) and trail making test part A (TMT) scores (administered at entry and at 1, 9, 21, and 54 months) over time.

RESULTS

There was no difference in the mean learning test coefficients (rate of change of score over time) between the three treatments: diuretic -0.31 (95% confidence interval -0.23 to -0.39), beta blocker -0.33 (-0.25 to -0.41), placebo -0.30, (-0.24 to -0.36). There was also no difference in the mean trail making coefficients (rate of change in time taken to complete over time) between the three groups: diuretic -2.73 (95% confidence interval -3.57 to -1.88), beta blocker -2.08 (-3.29 to -0.87), placebo -3.01, (-3.69 to -2.32). A less conservative protocol analysis confirmed this negative finding.

CONCLUSION

Treating moderate hypertension in older people is unlikely to influence, for better or for worse, subsequent cognitive function.