Prevalence of insulin glargine vial use beyond 28 days in a Medicaid population.

OBJECTIVES: Insulin glargine, one of the most commonly prescribed drugs for diabetes, has a 28-day limit on the use of a 10-mL (1000 units) multiple-dose vial once the bottle is punctured. If patients who are using smaller doses or are not adherent continue to use insulin glargine beyond the 28-day window, it can result in questionable stability and sterility of the product. The aim of this study was to determine the proportion of patients who used each insulin glargine vial for more than 28 days, the mean number of days the vial was used after 28 days, the reason for the extended use, and whether that use had any association with diabetes control and injection site infection.

METHODS: The study was conducted in 2 phases. Phase I was a retrospective database analysis of insulin glargine 10-mL vial use by the adult Medicaid population with type 2 diabetes served by Molina Healthcare to determine the proportion of patients who used each vial beyond 28 days. Phase II was a cross-sectional telephone interview to identify the reasons for the extended use.

RESULTS: Of the 269 patients identified, 81% used it for more than 28 days, with a mean of 43 days. Of the interviewed patients, 60% did not discard the vials after 28 days because of a lack of awareness. Patients who were aware of the 28-day limit were informed by a pharmacist or diabetes educator.

CONCLUSION: A large proportion of Medicaid patients were found to use insulin glargine past the recommended 28-day limit. More work is needed with a larger sample size to determine whether reasons besides lack of awareness affect the use of insulin glargine beyond its expiration and the role of pharmacists and diabetes educators in improving adherence to disposing of the drug after 28 days.