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One in four people with high blood pressure not taking their medication properly

Published:

Simple urine test can distinguish between treatment failure and failure to take drugs

Around one in four people prescribed drugs to lower longstanding blood pressure either just doesn’t take them at all or only part of the time, suggests a study of a simple technique designed to find out why drug treatment might not be working in these patients, and published online in the journal Heart.

Those referred for further treatment, because of “resistant hypertension” were most likely not to be taking their tablets properly, the findings show.

The authors analysed the urine samples of 208 patients with high blood pressure attending a specialist hypertension clinic. Some 125 were new referrals from primary care; 66 were follow up patients whose blood pressure control was poor; and 17 had been referred for renal denervation.

One in four of the 208 patients was not taking their blood pressure drugs properly: one in 10 (10%) was not complying with treatment at all; while a further one in seven (15%) was only taking them part of the time.

The authors acknowledge their sample size is small, but point to “alarmingly high levels” of complete non-adherence to prescribed drugs.

A majority of these patients in any secondary/tertiary care centre would routinely undergo many additional tests and procedures in search of the explanation for their apparent unresponsiveness to standard therapy prescribed in primary care,” they emphasise, adding that in around one in five cases, HP LC-MS/MS could potentially avoid all this.

In an accompanying editorial, Professor Morris Brown, of the Clinical Pharmacology Unit at the University of Cambridge, says that the technique could “solve at a stroke the problem of monitoring adherence and should rapidly transform practice.”

 “That most patients do not take all their drugs all the time was probably predictable,” he suggests. “But that 23% of those referred for renal denervation have no detectable drug in their urine was a shock,” he adds, especially given that there are considerable doubts about the effectiveness of this procedure, to say nothing of the waste of resources involved.

Chief Executive of Blood Pressure UK, Katharine Jenner, says “It is important to understand that even if you feel perfectly well, by keeping your blood pressure low, you are protecting your heart and blood vessels from damage and disease that could lead to a heart attack or stroke.

“If you have been prescribed blood pressure medicines but aren’t taking them, perhaps due to side effects, please speak to your doctor or nurse about changing your dose, or trying a different medication which may work better for you."

To find out more about blood pressure medication, click here. 

Authors:
Dr Maciej Tomaszewski, Department of Cardiovascular Sciences, University of Leicester, Leicester,
Professor Bryan Williams, Institute of Cardiovascular Science, NIHR University College London Hospitals Biomedical Research Centre, UCL, London, UK

High rates of non-adherence to antihypertensive treatment revealed by high-performance liquid chromatography-tandem mass spectrometry (HP LC-MS/MS) urine analysis

Online First doi 10.1136/heartjnl-2013-305063

Editorial:
Professor Morris Brown, Clinical Pharmacology Unit, University of Cambridge, Cambridge, UK Resistant hypertension: resistance to treatment or resistance to taking treatment?

Online First doi 10.1136/heartjnl-2014-305540