What constitutes controlled hypertension? Patient based comparison of hypertension guidelines.

Abstract

To investigate and quantify the extent to which variations in guidelines influence assessment of control of hypertension. Cross sectional study. Selected patients had hypertension assessed as controlled or uncontrolled with guidelines from New Zealand, Canada, the United States, Britain, and the World Health Organisation. 18 general practices in Oxfordshire. 876 patients with diagnosed hypertension and taking antihypertensive drugs. Proportion of patients with controlled hypertension according to each set of guidelines. The proportion of patients with controlled hypertension varied from 17.5% to 84.6% with the different guidelines after adjustment for the sampling method. All five sets of guidelines agreed on the classification for 31% (277) of the patients. The New Zealand guidelines calculate an absolute risk of a cardiovascular event. When this was taken as the standard half of the patients with uncontrolled hypertension by the United States criteria would be treated unnecessarily and 31% of those classified as having controlled hypertension by the Canadian guidelines would be denied beneficial treatment. Hypertension guidelines are inconsistent in their recommendations and need to make clear the absolute benefits and risks of treatment.