It's all a matter of necessity and concern: A structural equation model of adherence to antihypertensive medication.

Abstract

Hypertension is often treated pharmacologically, yet adherence is poor. Beliefs about antihypertensive medicine, i.e., the necessity-concern framework (NCF), are valuable for explaining adherence. Therefore, a model structure is transferred from hypercholesterolemia to hypertension, assuming a mediating role of the NCF. Patients with hypertension (n=273) were surveyed online about demographics, health- and treatment-related factors, control beliefs, necessity and concern beliefs about their medication, and adherence. The data were analyzed using structural equation modeling (SEM). Necessity was positively (β=0.26, p=0.009) and concern was negatively (β=-0.51, p=0.020) associated with adherence. The NCF mediated the influence of background variables on adherence. Necessity was associated with comorbidity (β=-0.36, p<0.001), treatment time (β=0.19, p=0.004), emotionally supportive doctor-patient communication (β=0.12, p=0.045), side effects (β=0.16, p=0.013), personal control (β=-0.13, p=0.022), and treatment control (β=0.29, p<0.001). Concern was associated with side effects (β=0.38, p<0.001) and beliefs about medicine in general being harmful (β=0.61, p<0.001). The model fit was acceptable (RMSEA=0.61). The transferred adherence model with the necessity-concern framework as a mediating factor was confirmed in hypertension, explaining more variance than previous approaches (23%). A personalized, emotionally supportive doctor-patient communication could be key to addressing beliefs about medicine and therefore to increasing adherence.