Predictors of self-reported noncompliance with antihypertensive drug treatment: a prospective cohort study

Persistence and compliance are different aspects of the broader concept of adherence to drug treatment. In a prior study, determinants of nonpersistence in a group of patients newly prescribed antihypertensive medications were examined.

To determine noncompliance among those who were persistent with therapy.

A prospective cohort study was conducted, in which individuals prescribed a new antihypertensive monotherapy were identified through a network of 173 pharmacies. Participants were interviewed by telephone twice during a three-month period. At the end of this period, individuals who reported still taking the medication initially prescribed were included in the analysis. Self-reported noncompliance was measured at three months. Data were analyzed using a multivariate logistic regression model.

Of 509 eligible participants, 118 (23.2%) reported noncompliance with their drug treatment. Noncompliance was significantly associated with the use of angiotensin-converting enzyme inhibitors (adjusted OR [AOR] 3.0; 95% CI 1.17 to 7.92) compared with the angiotensin II receptor blocker losartan, and with the belief that hypertension is not a risk factor for cardiovascular diseases (AOR 2.0; 95% CI 1.21 to 3.33). On the other hand, noncompliance was inversely associated with the use of more than four pills of medication per day (AOR 0.3; 95% CI 0.15 to 0.64).

Compliance with drug treatment could be improved by proper selection of medication, and by attempts to correct the false perceptions patients may have about hypertension. Further research is needed to better understand the clinical significance of a higher number of pills as a predictor of good compliance. Further research is also needed using different means of measuring noncompliance.