Cost, healthcare resource utilization, and adherence of individuals with diabetes using U-500 or U-100 insulin: a retrospective database analysis.

OBJECTIVE: To describe costs, healthcare resource utilization, and adherence of US patients receiving human regular U-500 insulin (U-500R), compared to patients receiving high-dose (>200 units/day) U-100 insulins (U-100) by subcutaneous injection for the treatment of diabetes.

METHODS: A retrospective analysis of data from Thomson Reuters MarketScan Research Databases (7/1/2008 to 12/31/2010). Difference-in-differences analyses were conducted on cost (medical, pharmacy, and overall costs) and on healthcare resource utilization variables (overall, diabetes-related, and non-diabetes-related medical visits). Adherence rates to the index insulins were assessed by proportion of days covered (PDC).

RESULTS: Seven hundred and eleven (19%) patients in the U-500R cohort and 1508 (6%) patients in the U-100 cohort met selection criteria. Propensity score matching resulted in 684 matched pairs. Mean change in annualized pharmacy costs was in favor of the U-500R vs the U-100 cohort (-$1258 vs $3345, a difference of -$4603, p < 0.0001). Mean overall cost increase in the U-500R vs the U-100 cohort was also lower ($1999 vs $9104, a difference of -$7105, p = 0.005). The proportion of patients with at least one coded hypoglycemic event during the 12-month post-index period was higher in the U-500R vs the U-100 cohort (17.1% vs 11.7%, p < 0.005), but neither hypoglycemia rate (2.73 vs 2.90 events per person) nor hypoglycemia-specific costs (mean $1669 vs $1543) were significantly different. No significant differences were noted between cohorts for change (post-pre) in any resource utilization category. PDC was greater in the U-500R vs the U-100 cohort (65.2% vs 39.5%, p < 0.0001).

LIMITATIONS: Claims data are not as accurate as empirical evaluation by a clinician. Glycemic control data were not available for this analysis.

CONCLUSIONS: In patients requiring high-dose insulin, treatment with U-500R vs high-dose U-100 insulins is associated with significant decreases in pharmacy and overall costs, slightly higher hypoglycemia incidence, no difference in hypoglycemia-specific costs or in resource utilization, and better adherence.