Comparison of Diabetes Medications Used by Adults With Commercial Insurance vs Medicare Advantage, 2016 to 2019

Key Points

Question

Were there differences in the initiation of treatment with newer medications to lower glucose levels between patients with type 2 diabetes insured by Medicare Advantage and those insured by commercial health plans from 2016 to 2019?

Findings

In this cohort study of 382 574 adults with type 2 diabetes aged 58 to 66 years, rates of initiation of glucagonlike peptide-1 receptor agonists, sodium-glucose cotransporter-2 inhibitors, and dipeptidyl peptidase-4 inhibitors were lower among Medicare Advantage enrollees than among commercial health insurance plan enrollees.

Meaning

These findings suggest that a better understanding of nonclinical factors contributing to treatment selection and efforts to promote equity in diabetes management are needed.

Abstract

This cohort study compares trends in initiation of treatment with glucagonlike peptide-1 receptor agonists, sodium-glucose cotransporter-2 inhibitors, and dipeptidyl peptidase-4 inhibitors by older adults with type 2 diabetes insured by Medicare Advantage vs commercial health plans.

Abstract

Importance

Glucagonlike peptide-1 receptor agonists (GLP-1RA), sodium-glucose cotransporter-2 inhibitors (SGLT2i), and dipeptidyl peptidase-4 inhibitors (DPP-4i) are associated with low rates of hypoglycemia, and postmarketing trials of GLP-1RA and SGLT2i demonstrated that these medications improved cardiovascular and kidney outcomes.

Objective

To compare trends in initiation of treatment with GLP-1RA, SGLT2i, and DPP-4i by older adults with type 2 diabetes insured by Medicare Advantage vs commercial health plans.

Design, Setting, and Participants

This retrospective cohort study used administrative claims data from a deidentified database of commercially insured and Medicare Advantage beneficiaries. Adults aged 58 to 66 years with type 2 diabetes who filled any medication prescription to lower glucose levels from January 1, 2016, to December 31, 2019, were compared between groups.

Exposure

Enrollment in a Medicare Advantage or commercial health insurance plan.

Main Outcomes and Measures

The odds of initiating GLP-1RA, SGLT2i, and DPP-4i treatment were examined for Medicare Advantage vs commercial insurance beneficiaries using 3 separate logistic regression models adjusted for year and demographic and clinical factors. These models were used to calculate adjusted annual rates of medication initiation by health plan.

Results

A total of 382 574 adults with pharmacologically treated type 2 diabetes (52.9% men; mean [SD] age, 62.4 [2.7] years) were identified, including 172 180 Medicare Advantage and 210 394 commercial beneficiaries. From 2016 to 2019, adjusted rates of initiation of GLP-1RA, SGLT2i, and DPP-4i treatment increased among all beneficiaries, from 2.14% to 20.02% for GLP-1RA among commercial insurance beneficiaries and from 1.50% to 11.44% among Medicare Advantage beneficiaries; from 2.74% to 18.15% for SGLT2i among commercial insurance beneficiaries and from 1.57% to 8.51% among Medicare Advantage beneficiaries; and from 3.30% to 11.71% for DPP-4i among commercial insurance beneficiaries and from 2.44% to 7.68% among Medicare Advantage beneficiaries. Initiation rates for all 3 drug classes were consistently lower among Medicare Advantage than among commercial insurance beneficiaries. Within each calendar year, the odds of initiating GLP-1RA treatment ranged from 0.28 (95% CI, 0.26-0.29) to 0.70 (95% CI, 0.65-0.75) for Medicare Advantage and commercial insurance beneficiaries, respectively; SGLT2i, from 0.21 (95% CI, 0.20-0.22) to 0.57 (95% CI, 0.53-0.61), respectively; and DPP-4i, from 0.37 (95% CI, 0.34-0.39) to 0.73 (95% CI, 0.69-0.78), respectively ( P < .001 for all). The odds of starting GLP-1RA and SGLT2i increased with income; for an income of $200 000 and higher vs less than $40 000, the odds ratio for GLP-1RA was 1.23 (95% CI, 1.15-1.32) and for SGLT2i was 1.16 (95% CI, 1.09-1.24).

Conclusions and Relevance

These findings suggest that Medicare Advantage beneficiaries may be less likely than commercially insured beneficiaries to be treated with newer medications to lower glucose levels, with greater disparities among lower-income patients. Better understanding of nonclinical factors contributing to treatment decisions and efforts to promote greater equity in diabetes management appear to be needed.