Clinical and Economic Outcomes of Patients with Type 2 Diabetes on Multiple Daily Injections of Basal-bolus Insulin (MDI) Therapy: A Retrospective Cohort Study.

PURPOSE: Therapy for patients with type 2 diabetes (T2DM) not achieving hemoglobin (Hb) A1c targets may progress from an oral antidiabetic drug (OAD) to added basal insulin and then to multiple daily injections of basal-bolus insulin (MDI); however, the relative clinical and economic burden experienced by patients prescribed MDI for T2DM is not well quantified. The intent of this work was to describe direct medical costs, health care resource utilization, and glycemic control in patients with T2DM exposed to MDI in a clinical practice setting. METHODS: This retrospective cohort study used administrative claims data (2012-2015, United States) from patients aged 18 to 64 years with T2DM prescribed OAD, basal insulin, or MDI therapy. Eligible patients had continuous enrollment from ≥6 months before to 12 months after the date of the index prescription drug claim. Patients eligible for inclusion in the MDI cohort had ≥2 pharmacy claims each for basal and bolus insulin from the index date through the postindex period. Glycemic control, defined as an HbA1c value of <7% during the last 9 postindex months, was assessed in a subset of patients with HbA1c data available from that period. Descriptive analyses were performed. FINDINGS: We identified 225,135 patients with T2DM and claims for an OAD (n = 188,230), basal insulin (n = 23,724), or MDI (n = 13,181). The mean age was 51 or 52 years in each cohort; 54% to 59% of patients in each cohort were men. The mean Charlson comorbidity index scores were 0.8, 1.4, and 1.8, respectively; the percentages of patients with obesity and diabetes-related complications were greatest in the MDI cohort compared with OAD and basal insulin cohorts. The mean direct medical costs (all-cause; year-2015 US $) were $9368 in the OAD cohort, $14,420 in the basal insulin cohort, and $25,624 in the MDI cohort; diabetes-related costs were $3396, $7285, and $13,538. In the OAD, basal insulin, and MDI cohorts, 7%, 9%, and 14% of patients had ≥1 hospitalization, and 17%, 20%, and 24% had ≥1 emergency department visit, while 5%, 7%, and 11% had ≥1 diabetes-related hospitalization, and 8%, 11%, and 15% had ≥1 diabetes-related emergency department visit. Glycemic control was found in 64%, 22%, and 15% of patients in the OAD, basal insulin, and MDI cohorts. IMPLICATIONS: These findings suggest that patients prescribed MDI therapy for T2DM have greater disease burden, experience greater medical costs and health care resource utilization, and exhibit poorer glycemic control than do patients treated with OAD or basal insulin therapy.