One in four patients with hypertension nonadherent to therapy

Major finding: A urine test available to commercial labs showed that 25% of patients were totally (10.1%) or partially (14.9%) nonadherent to treatment. Nonadherence was linearly associated with increased clinic systolic blood pressure, clinic diastolic blood pressure, and 24-hour mean daytime diastolic blood pressure (P < .006 for all).

Data source: High-performance liquid chromatography–tandem mass spectrometry urine screening and blood pressure measurements in 208 patients with hypertension.

Disclosures: The authors reported receiving research and other support from the British Heart Foundation and the National Institute for Health Research.

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Is the test ethical? Is overtreatment?

"A contentious question has been whether resistant hypertension is a pathogenetic subset of hypertension, justifying a search for ‘stratified medicines’; or is it an imaginary condition caused by doctors in white coats and patients who do not take their tablets?" commented Dr. Morris J. Brown.

"On the one hand, there is abundant evidence that primary aldosteronism causes 20%-25% of true treatment resistance," he added. But Tomaszewski et al. show that nonadherent patients "account for an almost identical, high proportion of supposed resistant hypertension. Furthermore, the authors answer not only the question ‘Is my patient taking his/her tablets,’ but also ‘How can I simply and cheaply find out?’ "

The authors "deftly side-stepped" questions related to the ethics of the test and what to do about the findings, said Dr. Brown. "Neither completion nor assent to urine testing could be compulsory," he emphasized. "But then, nor is progression to expensive tests for benign, curable causes of resistant hypertension – without resistance to treatment being first demonstrated."

Dr. Brown is a professor of clinical pharmacology at the University of Cambridge, England. He reported that he had no conflicts of interest. These remarks were taken from his editorial accompanying Dr. Tomaszewski’s report (Heart 2014 April 3 [doi: 10.1136/heartjnl-2013-305063]).



Urine testing of patients with hypertension revealed that 25% were partially or totally nonadherent to treatment, researchers reported online April 3 in the journal Heart.

Furthermore, nonadherence was linearly related to increased systolic and diastolic blood pressures during clinic visits and 24-hour mean daytime diastolic blood pressure (P < .006 for all), reported Dr. Maciej Tomaszewski of the University of Leicester, England, and his associates.

Using a urine test available to commercial labs, the investigators tested 208 patients for 40 of the most common antihypertensive medications and their metabolites by performing high-performance liquid chromatography–tandem mass spectrometry of spot urine samples. Patients were either newly referred (n = 125), followed up for inadequately controlled blood pressure (66), or referred for renal denervation (17), the investigators reported (Heart 2014 April 3 [doi: 10.1136/heartjnl-2013-305063]).

Nonadherence was particularly common among patients whose hypertension was inadequately controlled (28.8%) or who were referred for renal denervation (23.5%), the investigators said. Without routine urine screening, nonadherent patients might receive or undergo unnecessary tests, procedures, or treatments for perceived nonresponse to treatment, said Dr. Tomaszewski, who is also with the National Institute for Health Research (NIHR) Leicester Biomedical Research Unit in Cardiovascular Disease, and his colleagues.

Larger, multicenter studies should directly estimate biochemical nonadherence in other populations and assess the cost-effectiveness of screening for nonadherence compared with the overall cost of managing resistant hypertension, the investigators said.

Dr. Tomaszewski and five of his associates reported receiving research and other support from the British Heart Foundation and the NIHR.

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