Lowering cost share may improve rates of home glucose monitoring among patients with diabetes using insulin

Abstract

BACKGROUND: Not much is known about the extent to which lower cost share for blood glucose strips is associated with persistent filling. OBJECTIVE: To evaluate the relationship between cost sharing for blood glucose testing strips and continued use of testing strips. METHODS: This is a retrospective observational study using medical and pharmacy claims data integrated with laboratory hemoglobin A1c (A1c) values for patients using insulin and blood glucose testing strips. Diabetic patients using insulin who had at least 1 fill of blood glucose testing strips between 2010 and 2012 were included. Patients were divided into a low cost-share group (out-of-pocket cost percentage of total testing strip costs over a 1-year period from the initial fill < 20[%]; n = 3,575) and a high cost-share group (out-of-pocket cost percentage = 20[%]; n = 3,580). We compared the likelihood of continued testing strip fills after the initial fill between the 2 groups by using modified Poisson regression models. RESULTS: Patients with low cost share had higher rates of continued testing strip fills compared with those with high cost share (89[%] vs. 82[%], P < 0.001). Lower cost share was associated with greater probability of continued fills (adjusted risk ratio [[]aRR] = 1.05, 95[%] CI = 1.03-1.07, P < 0.001). Other patient characteristics associated with continued fills included type 1 diabetes diagnosis, types of insulin regimens, and health insurance plan type. In a subset analysis of patients whose A1c values at baseline were above the target level (8[%]) set by the National Committee for Quality Assurance guidelines, we saw a slight increase in magnitude of relationship between cost share and continued fills (RR = 1.06, 95[%] CI = 1.03-1.10, P < 0.01). CONCLUSIONS: There was a statistically significant association between cost share for testing strips and continued blood glucose self-monitoring. Among patients not achieving A1c control at baseline, there was an increase in the magnitude of relationship. Lowering cost share for testing strips can remove a barrier to persistence in diabetes self-management.