The effect of the content of the knowledge on adherence to medication in hypertensive patients

It was suggested that knowledge might influence the adherence to treatment in hypertension. Accordingly, in this study, we investigated the effects of content of knowledge on medication adherence and knowledge-based predictors of adherence to treatment in hypertensive patients.

This cross-sectional study included 227 hypertensive patients (70% female;mean age: 57+/-12 years), who were followed by cardiology and internal medicine clinics. The patients were asked to fulfill a questionnaire including 40 items. Besides the demographic and disease-related questions, the patients were also asked (1) the name of the drug, (2) the duration of the drug use;(3) the reason of using the drug;(4) the cause of hypertension;(5) the target level of hypertension;(6) the result of hypertension;(7) the side effects of antihypertensive medicines. Statistical analyses were performed using Chi-square, Fischer exact, Mann Whitney U tests and logistic regression analysis.

It was found that 163 (72%) were adherent and 64 (28%) were nonadherent to the treatment. Angiotensin-II receptor antagonist use (OR=4.405;95%CI: 1.561-12.365, p=0.022) and hypertension duration > or =5 years (OR=0.446;95%CI: 0.246-0.811, p=0.006) was found to be independently related to adherence. Among the knowledge-based variables, knowing the duration of use of the medicine (OR=6.822;95% CI: 1.478-31.241, p=0.075), the reason of use of medicine (OR=2.828;95% CI: 1.445-5.543, p=0.018), the cause of the hypertension (OR=3.447;95% CI: 1.889-6.290, p=0.037) and the target level of blood pressure (OR=12.859;95% CI: 5.045-32.640, p<0.001) significantly increased the adherence rates. On the other hand, knowing the name of the medicine (p=0.112) or the results of hypertension (p=0.719) had no effect on adherence, while knowing the side effects of the medicine (OR=0.607;95% CI: 0.340-1.084, p=0.005) had negative effect. The total number of correct answers was also higher in patients with adherence to treatment (p=0.002).

Patient knowledge about hypertension and medications is associated with higher adherence rates. However, it should be taken into consideration that the possible effects of knowledge may differ according to its content.