BACKGROUND: Adherence to oral antihyperglycemic agents (AHAs) is important for managing blood glucose levels and avoiding hospitalizations or diabetes complications. Previous studies have found that use of mail-order pharmacy dispensing channels results in greater adherence than use of community pharmacies, but the link between use of mail-order pharmacies and improved clinical outcomes has not been established.
OBJECTIVE: To compare the effect of mail-order and community pharmacy use on adherence to oral AHAs, hemoglobin A1c (A1c) level, and glycemic control, as well as emergency department (ED) and inpatient hospital use.
METHODS: This retrospective cohort study of administrative claims data from January 1, 2008, to December 31, 2016, included patients with Medicare Advantage Prescription Drug plan coverage with ≥ 2 claims for the same oral AHA and a diagnosis of type 2 diabetes mellitus (T2DM). Patients were indexed to the start of the most advanced oral AHA identified to begin study observations at the start of a new treatment and assigned to mail-order or community pharmacy cohorts based on which channel dispensed ≥ 80% of their oral AHA claims; all others were excluded. Mail-order and community pharmacy patients were 1:1 propensity score matched. Matched cohorts were compared on proportion of days covered (PDC), adherence (PDC ≥ 0.8), A1c level, glycemic control, and ED and inpatient use for measurement periods of 12, 24, 36, and 48 months post-index.
RESULTS: 19,307 mail-order and 19,307 community pharmacy users were matched. PDC was higher for mail-order pharmacy users at 12 months (0.93 vs. 0.82, P < 0.001) and sustainable through 48 months (0.87 vs. 0.77, P < 0.001). Adherence was also greater for mail-order pharmacy patients through 12 months (86% vs. 68%, P < 0.001) and sustainable through 48 months (78% vs. 62%, P < 0.001). Glycemic control as A1c < 7% was not significantly different, but control as A1c < 8% was greater for mail-order pharmacy users at 12 months (91% vs. 89%, P = 0.006) and was greater through 36 months (93% vs. 89%, P = 0.043). Effects on A1c level were not evident. Mail-order pharmacy users were less likely to have an ED visit within 12 months (26% vs. 28%, P < 0.0001), and the difference was observed through 36 months (50% vs. 54%, P < 0.0001). Similarly, fewer mail-order pharmacy users had an inpatient hospitalization within 12 months (17% vs. 19%, P < 0.0001), and the difference was observed through 48 months (43% vs. 47%, P = 0.009).
CONCLUSIONS: The results of the study demonstrate a benefit to patients who use mail-order pharmacies for chronic medications to treat T2DM. The study identified greater glycemic control, lower ED use, and lower hospitalization among individuals using mail-order pharmacies. These positive outcomes were evident in the near term and sustained over time.
