UCL News


Urine test for blood pressure drug adherence

29 August 2017

The use of a urine test for drug adherence can lead to a drop in blood pressure in patients who had been struggling to regularly take their blood pressure lowering tablets, according to a new study involving UCL researchers, published in Hypertension.

Blood pressure cuff

Of the 238 patients who underwent the urine test, 73 were not taking their blood pressure lowering tablets on a regular basis.

"Our study shows the therapeutic benefits of biochemical screening for non-adherence to antihypertensive treatment," said senior author Professor Maciej Tomaszewski (University of Manchester).

"The urine test creates an opportunity for patients and their doctors to discuss the barriers to regular taking of blood pressure lowering medications. The doctors can then act on these barriers and provide the support the patients need to adhere to the treatment regimes," he said.

The project involved researchers from the University of Manchester, the University of Leicester, UCL and Charles University, Prague, with collaborators from Central Manchester University Hospitals NHS Foundation Trust and University Hospitals of Leicester NHS Trust.

The data are consistent with previous research by the team which revealed more than one third of people with high blood pressure have not been taking their blood pressure medication as prescribed.

The research team tracked blood pressure changes in the 73 patients who had struggled to take their tablets regularly following their appointment at which the discussion of their initial urine test took place. 

The team noticed that systolic blood pressure fell on average by between 20 and 30 mmHg between the urine test and the final clinic visit.

The majority of patients who underwent the urine test became completely adherent to their prescribed blood pressure lowering treatment and a further 30% of patients improved their adherence. 

In terms of public health, such a significant drop in blood pressure may translate into an approximate 45% reduction in risk of coronary heart disease and a 65% reduction in the risk of stroke.

"The blood pressure drop we see as a result of this test being used in clinical practice is likely to save lives. It is also likely to have an important impact on health economy if this test is used routinely," Professor Tomaszewski said.

A previous study has shown that non-adherence to blood pressure-lowering tablets in the United States cost the health economy $18.5 billion.

The most common non-intentional non-adherence often results from forgetting to take the drugs, because so many of them are prescribed.

Co-author Professor Bryan Williams (UCL Institute of Cardiovascular Science) said: "This research is important because it shows that patients taking multiple blood pressure pills are often failing to take all of their medications and this leaves them at increased risk of poor blood pressure control and risk of stroke and heart disease."

"The research shows that identifying this problem can lead to better adherence to treatment and better blood pressure control and will reduce the risk of these patients. These techniques for monitoring treatment should be more widely available on the NHS to improve patient outcomes," he said.

First author Dr Pankaj Gupta (University of Leicester and University Hospitals of Leicester NHS Trust) said: "High blood pressure is the single most important risk factor for premature death internationally. Conversion of the majority of non-adherent hypertensive patients to adherence with a significant drop in blood pressure is an important breakthrough, given that previous studies showed limited benefits from complex and costly interventions."

Co-author Dr Prashanth Patel (University Hospitals of Leicester NHS Trust) said: "Although treatments available to doctors are effective, target blood pressures are only achieved in 40-50% of patients. We suggest that repeated urine should be considered as a potential therapeutic approach to non-adherence in patients with high blood pressure."



  • Blood pressure cuff (Credit: Quinn Dombrowski, Source: Flickr)


Media contact

Chris Lane

Tel: +44 (0)20 7679 9222

Email: chris.lane [at] ucl.ac.uk