This study will compare hemoglobin a1c (HbA1c) and cardiovascular (CV) outcomes among patients with type 2 diabetes newly initiating a GLP1-receptor agonist or basal insulin.

The 2019 ADA-EASD clinical treatment guidelines recommend a GLP-1RA over basal insulin for patients with type 2 diabetes with suboptimal glycemic control despite metformin and a second-line glucose lowering agent. The basis of this recommendation is due to the side effect profiles of these two medications (i.e. reduced risk of hypoglycemia, some weight loss with GLP-1RA), convenience (once weekly injection) and the fact that the price of insulin has skyrocketed in recent years. Prior head-to-head randomized trials (EAGLE, LEAD 5) comparing select GLP-1RA and basal insulin have found mixed results. In EAGLE, adding either insulin glargine or liraglutide to patients with poorly controlled type 2 diabetes found no differences in the primary outcome (percentage of people reaching HbA1c < 7%). In LEAD 5, liraglutide was associated with a slightly greater HbA1c reduction than glargine, however the dose of insulin was approximately 50% less than the dose used in EAGLE. The objective of this observational study is to describe the comparative effectiveness and safety of newly initiating a GLP1RA versus basal insulin in patients with type 2 diabetes using metformin and another oral glucose lowering medicine.

Inclusion Criteria:

• Age>=18 years
• at least 180 days of continuous enrollment prior to index date
• at least 1 Type 2 diabetes diagnosis code prior to index date
• (for cohort #1) at least 2 metformin dispensings prior to index date AND days supply overlap on cohort entry date (with 14 days of grace period before)

Exclusion Criteria:

• any type 1 diabetes diagnosis code prior to index date
• medullary thyroid carcinoma, multiple endocrine neoplasia type 2 (both black box warnings) prior to index date
• h/o pancreatitis
• h/o recurrent hypoglycemia (i.e. more than 1 hospitalization / emergency department encounter in primary diagnosis position for hypoglycemia)
• index injectable is a combination of GLP1-RA plus insulin
• index GLP1-RA is Saxenda (indicated for weight loss) or liraglutide at 3.0mg dose
• index insulin regimen includes both basal and prandial insulin, or premixed insulin
• Any prior GLP1-RA use (Applied washout for 180 days)
• Any prior insulin use; Sometimes insulin is transiently used at diagnosis (Applied washout for 180 days)
• Secondary diabetes
• Gestational diabetes
• Nursing home admission (because we don't have pharmacy claims)
• Age <18 years
• Chronic kidney disease stage 4-6
• Advanced cancer
• End stage renal disease

For A1c cohort only:

-HbA1c >12%

Patients with type 2 diabetes with prior and concomitant use of metformin and other oral anti diabetic agents