Failures of physicians to intensify antihypertensive treatment and of patients to adhere to medications contribute to the difficulty in controlling hypertension, a study of coronary artery disease (CAD) patients shows.
Furthermore, the research suggests non-adherence may explain why patients often fail to get their blood pressure (BP) under control despite having antihypertensive medications intensified.
A team led by Dr Michael Ho of Denver Veterans Affairs Medical Center, USA studied medical records of 10,447 CAD patients enrolled on the healthcare system at Kaiser Permanent of Colorado.
Most patients (87.2%) had controlled BP (systolic [S]BP; ≤140mmHg) that remained stable over time (median follow-up, 4.5 years).
Meanwhile, 7.5% of patients had high BP (SBP >140mmHg) that became controlled over time, and just 5.3% had high BP that remained high throughout the study period.
Patients with high BP that remained uncontrolled and those whose BP was brought under control by the end of observation were more likely to be non-adherent to medication, defined as less than 80% of days covered, than those with normal BP that remained under control.
They were also more likely to have their therapy intensified, defined as a dosage increase for any drug or an increase in the total number of antihypertensive medications.
As reported in the Archives of Internal Medicine, multivariable analysis indicated that patients with persistently uncontrolled BP were more likely to be nonadherent to medication and to have had their therapy intensified relative to those with high BP that was brought under control over time.
Similarly, patients with persistently uncontrolled BP were more likely to be nonadherent to medications and to have had therapy intensified than those with normal BP that remained controlled.
The authors say these findings “suggest that medication nonadherence may explain why BP levels remained elevated despite intensification of treatment with antihypertensive medications”.
In contrast, patients with high BP that was brought under control were more likely to have therapy intensified but no more likely to be nonadherent to medications than those with normal BP that remained controlled.
This suggests that having therapy intensified and taking the medications as prescribed resulted in these patients’ decreases in BP levels over time, the authors note.
They conclude: “Successful blood pressure control is seen with a combination of intensification and adherence, suggesting that therapy intensification must be coupled with interventions to enhance medication adherence.”