Increased Stroke Risk Linked to Poor Adherence in Hypertension Patients

Patients with poor adherence to antihypertensive medication were much more likely to die from a stroke than were patients with high adherence, according to the results of a new study.

Adding further evidence of the benefits of medication adherence, the results of a study published online on July 16, 2013, in the European Heart Journal, indicate that hypertensive patients who fail to take their medications as prescribed are more likely to be hospitalized or die from a stroke than adherent patients.

Researchers from Finland linked records from the Statistics Finland Labour Market data file with medication records from the National Drug Reimbursement Register and the Drug Prescription Register from 1995 to 2007 to determine the risk of stroke in hypertensive patients taking antihypertensive medications. Adherence levels and stroke risk were calculated for each year of the study. Participants were categorized as adherent if they took their medications correctly at least 80% of the time. All patients included in the study were older than 30 and had no previous history of stroke or cardiovascular events.

Of the 73,527 patients included in the study, 2144 died and 24,560 were hospitalized due to stroke. The results indicated that, throughout the 12-year study period, non-adherent patients were consistently more likely to suffer stroke events that led to death or hospitalization than were adherent patients. After 2 years, non-adherent patients were 3.81 times more likely to die from a stroke and 2.74 times more likely to be hospitalized from a stroke than were adherent patients. After 10 years, non-adherent patients were still 3 times more likely to die and 1.71 times more likely to be hospitalized due to stroke than were adherent patients.

During the year patients experienced a stroke, non-adherent patients had odds 5.7 times greater for fatal stroke and 2 times greater for nonfatal stroke than did adherent patients. Among patients who had been prescribed drugs that acted on the renin-angiotensin system combined with diuretics or beta-blockers, risk for fatal stroke increased 7.5 times and risk for stroke leading to hospitalization increased 3.9 times for non-adherent patients compared with adherent patients in the year these events occurred.

The researchers also found that as adherence decreased, the risk of hospitalization or death from stroke increased. After the initial analysis, patients were further categorized as having high adherence, intermediate adherence, or poor adherence. During the year of the stroke events, patients with intermediate adherence were 3.6 times more likely to die from stroke than were patients with high adherence. Patients with poor adherence had a risk of death 7.99 times greater than those with high adherence. Similar results were found for hospitalizations due to stroke.

These results “confirmed that the near- and long-term risk of fatal and non-fatal stroke increased each step down the level of adherence,” the authors write. They conclude that their findings underscore the role of medication adherence in preventing serious complications.