Hypertension and Diabetes Medication Adherence in Colorado: Results from a Population-Based Survey and Comparison to All Payer Claims Data

BACKGROUND: Adequate control of hypertension and diabetes are of significant public health importance. Based on data from the National Health and Nutrition Examination Survey 1999-2000, less than 40% of people with hypertension and people with diabetes had their condition controlled. Studies have shown that medication adherence is associated with control of these conditions, and treatment and control of these conditions reduces adverse health outcomes. The objectives of this study were to assess diabetes and hypertension medication adherence rates and compare results from two data sources in Colorado.

METHODS: Colorado’s The Attitudes and Behaviors Survey on Health (TABS) is a population-based cell phone and landline telephone survey. Adult diabetes and hypertension medication adherence rates were calculated from the 2012 TABS data using a scaled composite of eight self-reported adherence variables.  TABS data analysis included assessment of barriers to adherence and adherence rates by demographics and health conditions. Adult hypertension medication adherence rates, assessed through prescription medication claims as members for whom the proportion of days covered exceeded 80%, were separately calculated from the Colorado All Payer Claims Database (CO-APCD) and analyzed by insurance type and geographic region of residence. 

RESULTS: Based on TABS data, hypertension and diabetes medication adherence rates were 76.7% and 73.6%, respectively. Low hypertension and diabetes medication adherence were more likely among younger adults, the uninsured, those with low socioeconomic status, minorities, and those limited in any activities by mental conditions. Low hypertension medication adherence was also more likely among adults with self-reported uncontrolled hypertension and those reporting they do not have someone in the health field to call with questions about medications. The most commonly reported barriers for both hypertension and diabetes medication adherence were being worried that the medication would negatively affect their health, inconvenience of taking medication more than once per day, and simply forgetting to take the medication. TABS and CO-APCD estimates of hypertension medication adherence were similar overall (76.7% and 74.4%, respectively) and by insurance type and geographic region of residence. 

CONCLUSIONS: Approximately 1 in 4 adult Coloradans do not adhere to their hypertension and diabetes medication regimens. The population-based survey results were similar to the claims database results and might be an adequate data source where claims data are not available. Results of identified sub-populations with low adherence and barriers to adherence can be used within Colorado’s clinical quality improvement project to provide technical assistance to targeted clinics to increase adherence rates.