Effect of herbal medicine use on medication adherence of cardiology patients

Purpose: Herbal drug use for cardiovascular disease is frequent and growing rapidly. The aim of this study is to investigate the effect of herbal medicine use on medication adherence of cardiology patients.

Methods: All patients admitted to the outpatient cardiology clinics, who had been prescribed at least one cardiovascular drug before, were asked to complete a questionnaire. Participants were asked if they have used any herbals during the past 12 months with an expectation of beneficial effect on health. Medication adherence was measured by using the Morisky Scale. High adherence was defined as a Morisky score <2 and a score ≥ 2 was accepted as low adherence in our study.

Results: Totally 390 patients (54.9% male and 45.1% female patients, mean age 58.9) participated in our study. 29.7% of them had consumed herbals in the past 12 months. The median Morisky score was significantly higher in herbal users than nonusers (p<0.001). Rate of low adherence, according to the Morisky Scale, was also higher in herbal users (61.2% vs. 29.9%, p<0.001). Number of herbals used was moderately correlated with the Morisky score (ρ=0.313, p<0.001). In stepwise, multivariate logistic regression analysis, herbal use was significantly associated with low medication adherence (OR: 3.76, 95% CI 2.36-6.09, p<0.001).

Conclusion: Herbal use was found to be independently associated with low medication adherence in our study population. Further studies are needed to elucidate the effect of herbal medicine use on medication adherence of cardiology patients.