Poor medication adherence may be to blame in many cases of persistent high blood pressure, based on results of a clinical trial testing a novel therapy for resistant hypertension.
Published in JAMA Hypertension, this study looked at the impact of medication adherence on a treatment for resistant hypertension called renal denervation.
Renal denervation is a minimally-invasive procedure that sends radiofrequency energy to the renal arteries, which supply the kidneys with blood. This procedure is used as a last resort for patients with resistant hypertension who don’t respond to blood pressure-lowering medication. However, renal denervation is still relatively new and findings on its ability to treat hypertension are inconsistent.
To learn more, researchers conducted the SYMPATHY trial, which included 139 Dutch patients with resistant hypertension. Between 2013 and 2016, 95 patients were randomly assigned to receive renal denervation, while 44 received usual care. Patients were followed for six months, during which time researchers tracked both blood pressure and medication adherence. Although patients were unaware that medication adherence was being monitored, it was tracked using blood tests that detect levels of medication in the blood.
Based on results, an estimated 80% of patients had poor medication adherence throughout the study period. After analysis, researchers found that success of the renal denervation procedure depended on whether patients took their medications or not. For example, among all patients, those in the control group actually had lower blood pressure at six months than those receiving renal denervation. However, renal denervation appeared to lower blood pressure when analyzing data from patients who took their medications consistently.
Authors also note that nearly one-third of patients fluctuated with medication adherence throughout the study period.
What this study shows, according to experts, is that medication adherence is extremely poor among patients with resistant hypertension, especially when patients don’t know they’re being monitored. Findings also suggest that changes in medication adherence are common and could interfere with study outcomes. As a result, experts encourage the use of blood tests to track medication adherence in clinical trials. Authors also highlight the need for better medication adherence in patients with resistant hypertension, as poor medication adherence can negatively impact outcomes.