Significant literature exists on the effects of medication adherence on reducing healthcare costs, but less is known about the effect of medication adherence among Medicare low-income subsidy (LIS) recipients. This study examined the effects of medication adherence on healthcare costs among LIS recipients with diabetes, hypertension, and/or heart failure.
This retrospective study analyzed Medicare claims data (2012-2013) linked to the Area Health Resources Files. Using measures developed by the Pharmacy Quality Alliance, adherence to 11 medication classes was studied among patients with 7 possible combinations of the diseases mentioned. Adherence was measured in 8 categories of proportion of days covered (PDC): ≥95%, 90% to 25%. Annual Medicare costs were compared across adherence categories. A generalized linear model was used to control for patient/community characteristics.
Among patients with only one disease, such as diabetes, patients with the lowest adherence (PDC .05). Among patients with multiple chronic conditions, patients’ adherence to medications for fewer diseases had higher costs.
Greater medication adherence is associated with lower Medicare costs in the Medicare LIS population. Future policy affecting the LIS program should encourage better medication adherence among patients with chronic diseases.