OBJECTIVES: To estimate healthcare costs among adult patients with type 1 diabetes (T1D) in routine clinical practices in the US.

METHODS: This retrospective cohort study analysed Merative MarketScan^® data (1-Jan-2014–30-Jun-2019) for adults (≥18 years) with prevalent T1D, defined as ≥2 claims for T1D ≥30 days apart, a ratio of T1D to type 2 diabetes diagnosis codes >0.5 with either a glucagon prescription or no record for oral hypoglycemics (except metformin), or a urine acetone test prescription prior January 2017 (index). Continuous health plan enrolment was required during 12-month baseline and ≥1 month of follow-up. Annualized T1D-related costs during follow-up were reported by health plan (Commercial, Medicare, or Medicaid).

RESULTS: A total of 73,861 Commercial (mean age [SD]: 44.8 [12.9] years; 48.1% female), 21,726 Medicare (73.6 [6.6] years; 47.7% female), and 10,959 Medicaid patients (45.4 [14.2] years; 64.7% female) were included (median follow-up: 30, 12, 30 months, respectively). Annualized T1D-related costs were highest for Medicaid patients ($29,706), followed by Medicare ($23,036) and Commercial patients ($17,487). Inpatient care was the primary cost driver, comprising 59% (Medicaid), 51% (Medicare), and 32% (Commercial) of costs. Insulin and diabetes-related (including glucose monitoring and insulin pumps) accounted for more T1D-related costs in Commercial patients (27% and 14%) than Medicare (16% and 4%) or Medicaid patients (14% and 3%). Outpatient care contributed primarily to T1D-related costs of Medicare patients (20%), followed by Commercial (15%) and patients (10%). ER visits and diabetic ketoacidosis events were larger T1D-related cost drivers in Medicaid patients (6% and 6%) than Medicare (3% and 1%) and Commercial patients (4% and 2%).

CONCLUSIONS: Medicaid enrollees had higher costs than Medicare or Commercial enrollees. Inpatient care, ER visits and diabetic ketoacidosis events contributed more to Medicaid costs than for Medicare and Commercial plans, with higher insulin and equipment use in Commercial enrollees.