Diabetes patients' medication underuse, illness outcomes, and beliefs about antihyperglycemic and antihypertensive treatments

Abstract

Objective: To determine how patients' beliefs about antihyperglycemic and antihypertensive medications relate to medication underuse and health status.

Research Design and Methods: In diabetes patients from an economically distressed region, we assessed perceived necessity and harmfulness for antihyperglycemics (n=803) and antihypertensives (n=573), past year's medication underuse, hemoglobin A1c (HbA1c), systolic blood pressure (SBP) and diastolic blood pressure (DBP).

Results: After correction for multiple analyses, multivariate models indicated that perceived need for antihyperglycemic medication was associated with being younger, prescribed insulin, and prescribed multiple medications. Concern about antihyperglycemics was associated with being younger, African-American, dissatisfied with information received about medication, and of low health literacy. For antihypertensives, perceived necessity was associated with having numerous medical comorbidities and being dissatisfied with medication information; concern was associated with being younger, dissatisfied with information received about medication, and of low health literacy. Up to half of patients underused at least one of the types of medication, many of whom attributed this to cost. For both types of medications, concern was significantly associated with both cost-related and non-cost related underuse, and antihypertensive concern was associated with higher SBP and DBP.

Conclusions: Even after adjusting for economic factors, patients who are younger, African-American, or of low health literacy are especially concerned about medication harmfulness, which is in turn associated with medication underuse and higher blood pressure. To enhance adherence and outcomes, interventions should address patients' underlying concerns about potential adverse treatment effects, and tailor on both cultural factors and health literacy.