Non-adherence to antihypertensive medication is very common among resistant hypertensives: results of a directly observed therapy clinic

Abstract

Resistant hypertension is common among the hypertensive population with reported prevalence of 12 to 15%. These patients have a higher cardiovascular risk and consequently a poorer cardiovascular prognosis. Suboptimal adherence with antihypertensive medication is a common contributing factor in apparent treatment-resistant hypertension. Patients were observed taking their medications under direct supervision at our directly observed therapy (DOT) clinic. At the DOT clinic visit, patients were fitted with a 24-h ambulatory blood pressure (ABP) monitor and each drug, at currently prescribed dose, was administered by a nurse; at an hourly interval and patient observed for 7 h. ABP readings between pre and post DOT clinic were compared. Fifty out of 56 patients had complete data on the ABP. Twenty four were female and the mean (s.d.) age was 62.0 (11.0) years. On the basis of the study methods that differentiated patients according to their BP response during the DOT clinic, twenty-five (50.0%) patients were deemed to be truly resistant (24-h ambulatory systolic blood pressure (SBP) fall <5 mm Hg) and the remaining 25 were deemed to have clinically significant non-adherence (24-h ambulatory SBP fall ⩾5 mm Hg) to prescribed therapy. In non-adherent patients, the mean 24-h ambulatory BP drop observed was 19.5/9.4 mm Hg (P<0.001 for both). Our results suggest that non-adherence is very common among patients considered to have apparent treatment-resistant hypertension. DOT clinic can be an effective method of identifying the truly resistant hypertensive patients.

Renal Denervation in Patients With Uncontrolled Hypertension and Confirmed Adherence to Antihypertensive Medications

“…However, nonadherence may be a factor in why some patients did not respond or had poorer BP control at 6 months, although this cannot be confirmed. It is well‐known that a substantial proportion of patients labelled with a diagnosis of “resistant hypertension” are found to be nonadherent on direct testing . One of the main criticisms aimed at SYMPLICITY HTN‐3 was that assessment of adherence to antihypertensive treatment prior to enrollment and during the course of the study was not adequate .…”

“…In one center, patients considered for RDN were admitted to the hospital for directly observed medication administration and monitoring of BP. At the other center, adherence was assessed by directly observed medication administration in an outpatient setting followed by repeat ABPM …”

How to Screen for Non-Adherence to Antihypertensive Therapy

“…Twenty-five percent of non-adherent patients were reported to develop symptomatic hypotension when assessed using this method [43]. There are also anecdotal reports of non-adherent patients being admitted to intensive care due to a precipitous drop in blood pressure driven by ingestion of previously avoided prescribed medications.…”

Hypertension – state of the art 2017

“…Half of patients thought to have resistant hypertension have been found to be completely or partially non-adherent. 16 Measures of adherence can take the form of traditional patient interviews, pill counts, medication refill queries or admission to hospital for directly observed therapy and measurement of BP response. High-performance liquid chromatography-tandem mass spectrometry analysis of the urine gives clinicians and researchers a highly sensitive and convenient method to screen for antihypertensive drugs in blood or urine samples.…”