Two in five people taking antihypertensives do not adhere fully to their medication, Hypertension reports, while one in seven don’t take any of their prescribed antihypertensive at all.

Researchers measured levels of antihypertensives in urine and serum in 676 patients from the UK. Of these, 41.6 per cent showed total or partial non-adherence, while 14.5 per cent showed total non-adherence. Women were 65 per cent more likely to be non-adherent than men. Each additional antihypertensive increased the likelihood of non-adherence by 85 per cent. Each 10-year rise in age reduced the risk of non-adherence by 33 per cent.

Diuretics were significantly more likely to be associated with poor adherence than the other four groups of antihypertensive. Indeed, being prescribed diuretics increased the risk of non-adherence by 65 per cent.

The authors, who validated the analytical method in 672 patients recruited in Prague with broadly similar results, comment that biochemical assessment may prevent unnecessary investigations and escalation of treatment. In addition, “simple changes”, such as reducing the number of medications or single pill combinations, will improve adherence and enhance blood pressure control.

“This is a simple, relatively inexpensive and robust test,” says study author Prashanth Patel from the Department of Cardiovascular Sciences at the University of Leicester. “It has anecdotally changed the management of hypertension in many centres that use the test.”

^{Hypertension 2017; 69:1113-1120}