Differences in hypoglycemia event rates and associated cost-consequence in patients initiated on long-acting and intermediate-acting insulin products

Objective: To compare hypoglycemia event rates in patients initiated on long-acting insulin analog (glargine) or intermediate-acting insulin (NPH) and to analyze the associated cost-consequence from a managed care perspective. Study design: A retrospective analysis of pharmacy and medical claims and electronic laboratory result data using a southeastern United States managed care health plan. Methods: Patients newly initiated on glargine or NPH between July 1, 2000 and August 31, 2002 were included. Hypoglycemia events were identified from medical claims by their ICD-9-CM codes. Multivariable techniques were used to compare hypoglycemia event rates between cohorts. Results: A total of 1434 patients were eligible (glargine = 310, NPH = 1124). The mean age was 53 years 17 years and 51% of patients were male. The mean treatment duration was 8.6 months 4.5 months. Multivariate analyses showed that patients in the NPH group had a higher hypoglycemia event rate than the glargine group (18.3 versus 7.3 per 100 patients per year; p = 0.009). The number needed to treat (glargine versus NPH) to avoid one hypoglycemia event per patient per year was nine patients at an A1 C of 7%. The mean annual index medication cost was $47 more for glargine ($390) than for NPH ($343) per patient per year (p = 0.042). The mean cost per hypoglycemia event was $1087 (95% CI: $764-$1409). Conclusions: Patients treated with glargine had significantly lower hypoglycemia event rates compared to the NPH group. The risk difference indicated that one hypoglycemia event would be avoided for every nine patients treated with glargine instead of NPH. The cost increase associated with treating nine patients with glargine rather than NPH is less than the cost of treating one hypoglycemia event. In this population, the savings associated with reduced hypoglycemic events more than offset the increased acquisition cost associated with glargine.