Beliefs about medication in participants with inadequately controlled hypertension – Findings from the STAAB Cohort Study

Decisions about taking antihypertensive medication as prescribed are likely to be influenced by patients' beliefs about medication. We assessed the influence of selected patient beliefs about medication on blood pressure (RR) control in subjects treated for arterial hypertension.

STAAB is a strictly controlled population-based prospective cohort study in inhabitants of Würzburg, aged 30 – 79yrs. Inadequately controlled RR was defined as systolic RR > 140/90 mm/Hg despite antihypertensive medication. We used the BMQ-Specific (Beliefs about Medicines Questionnaire) to evaluate the specific necessity of prescribed medication (5 items; range 0 – 25) and specific concerns about medications (6 items; range 0 – 30). Higher scores indicate higher levels of concern or necessity. Multivariable logistic regression, adjusted for sociodemographic status (age, sex, education), body mass index > 25 kg/m2, and self-reported smoking was used.

Overall, 156 participants free of cardiovascular disease but with hypertension and on antihypertensive treatment could be analysed: median age 62.2 years, 52.6% women; inadequately controlled RR in n = 68 (43.6%). Inadequately controlled RR was associated with lower concerns (OR 0.92, 95%CI 0.85 – 0.99), lower age (OR per decade 0.65, 0.44 – 0.95), and smoking (OR 2.82, 1.01 – 7.87). No significant associations were found for specific necessity.

In the present study we could not condirm the intuitively attractive association between inadequately controlled RR and the belief regarding the necessity of prescribed medication. By contrast, we observe an inverse association between concerns about medication and inappropriately controlled RR. A possible explanation might be that subjects with a higher level of concern may be particularly well-informed, thus better adhering to physician's advice: these subjects may have a stronger inclination to take their medication as prescribed in order to thereby avoid additional treatment with even more substance classes.