Health Outcomes Associated with Initiation of Basal Insulin After 1, 2, or ≥ 3 Oral Antidiabetes Drug(s) Among Managed Care Patients with Type 2 Diabetes

BACKGROUND: Type 2 diabetes mellitus (T2DM) is a progressive disease. Despite starting with single oral antidiabetes drug (OAD) therapy and then adding OAD(s), most patients eventually require insulin therapy to achieve and maintain glycemic control. The timely initiation of insulin therapy could help patients with T2DM whose glycemic control is not adequately maintained using OADs alone. OBJECTIVE: To describe and compare baseline characteristics and assess real-world health outcomes associated with initiating basal insulin after 1 OAD, 2 OADs, or ≥ 3 OADs among T2DM patients. METHODS: Data were analyzed from adult T2DM patients in a U.S. managed care claims database (IMPACT) who initiated a basal insulin (from January 1, 2001, to December 31, 2011) with continuous health plan enrollment for 6 months before (baseline) and 12 months after (follow-up) insulin initiation and who had at least 1 OAD prescription. Outcome measures according to the number of OADs used were (a) treatment discontinuation, (b) glycated hemoglobin (A1c) levels, (c) proportion of patients experiencing hypoglycemia, (d) health care resource utilization, and (e) costs. RESULTS: Data from 71,988 patients were included (1 OAD: 19,168 patients [26.6%]; 2 OADs: 29,112 [40.4%]; and ≥ 3 OADs: 23,708 [32.9%]). All baseline characteristics, except nephropathy, were significantly different across the 3 groups. At baseline, when compared with the 1 OAD or 2 OADs groups, the ≥ 3 OADs group was less likely to be female or have macrovascular disease and had experienced fewer hypoglycemic events and hospitalization as well as lower costs. At follow-up, treatment discontinuation rates were 36.0%, 27.6%, and 21.4% for the 1 OAD, 2 OADs, and ≥ 3 OADs groups, respectively. A1c reduction was −1.33%, −1.05%, and −0.86%, respectively. The proportion of patients experiencing any hypoglycemia was 4.7%, 3.8%, and 3.3% at baseline; and 3.7%, 3.5%, and 3.1% at follow-up for the 1 OAD, 2 OADs, and ≥ 3 OADs groups, respectively. In all 3 groups, health care costs decreased compared with baseline, particularly in the 1 OAD and 2 OADs groups, with decreased inpatient costs offsetting increased drug costs. CONCLUSIONS: This real-world analysis shows that there are significant baseline differences in patients with T2DM on 1 OAD, 2 OADs, or ≥ 3 OADs when adding insulin therapy. All 3 groups had significant improvements in clinical and economic outcomes compared with baseline, yet at different magnitudes. These data contribute to a growing body of evidence supporting the timely initiation of insulin therapy for T2DM patients not maintaining glycemic control with OADs.