Physicians often fail to confirm treatment adherence in patients with apparent treatment-resistant hypertension, suggesting that physicians cannot rely on pharmacy records, pill counts, and patient reports alone when nonadherence is suspected, according to a research letter published in JAMA Internal Medicine.
“Among patients with apparent treatment-resistant hypertension, nonadherence to treatment is common,” Marcel Ruzicka, MD, PhD, FRCPC, of the Kidney Research Center and the Renal Hypertension Center in the division of nephrology at the University of Ottawa and the Ottawa Hospital Research Institute, Ontario, Canada, and colleagues wrote. “Pharmacy refill data, the Morisky scale, and pill counts are limited tests for determination of nonadherence.”
Due to the limitations of other tests, Ruzicka and colleagues conducted a prospective cohort study at a specialized hypertension center to evaluate the association between treatment adherence and directly observed therapy in patients with apparent treatment-resistant hypertension.
Patients eligible for the study were aged at least 18 years, had apparent treatment-resistant hypertension and were receiving at least three BP-lowering drugs. Those with apparent treatment-resistant hypertension had a daytime mean systolic BP of 135 mm Hg or greater on 24-hour ambulatory BP monitoring.
Researchers used standard questioning by hypertension clinic nurses to assess a patient’s adherence to BP-lowering drugs prior to the study. In addition, researchers took pill counts and reviewed pharmacy records for the 6 months leading up to the study. Only patients who had complete agreement between pharmacy records, pill counts, and treatment regimens were enrolled in the study.
Patients who underwent directly observed therapy were given their treatment by a nurse, who monitored their BP response until peak BP effect was reached. Participants underwent 24-hour ambulatory BP monitoring after reaching peak BP response and again at 1 month.
Researchers enrolled 60 consecutive patients with a mean age of 62.1 years into the study. Of those, 48 underwent directly observed therapy and monitoring and 46 completed the 1-month follow-up.
Among the 48 patients who received directly observed therapy, 34 (71%) had daytime systolic BP of 135 mm Hg or greater, for a mean decrease of 3 mm Hg in systolic blood pressure, indicating that they still had apparent treatment-resistant hypertension.
In 14 (29%) of 48 patients, systolic BP decreased by 26 mm Hg after directly observed therapy and treatment-resistant hypertension was considered resolved. Similar results were reported in 14 (30%) of the 46 patients who completed the 1-month follow-up, and those patients were no longer considered to have treatment-resistant hypertension.
Researchers noted that the results suggest that the rate of BP nonadherence was high despite patient self-reports that they were adherent and pharmacy records and pill counts that indicated they were adherent to treatment.
“Overall, the findings suggest that rigorous methods of adherence assessment and intervention such as [directly observed therapy] should be considered for patients with apparent treatment resistant hypertension,” Ruzicka and colleagues wrote. – by Erin Michael
Disclosures: Ruzicka reported receiving grants from Physicians Services Incorporated and The Ottawa Hospital Academic Medical Organization – Innovation Fund Provincial Oversight Committee during the conduct of the study. Please see study for all other authors’ relevant financial disclosures.