---
type: source
title: "Racial and Ethnic Disparities in GLP-1 Prescribing Narrow With Medicaid Coverage Expansion (Wasden 2026, Obesity)"
author: "Wasden et al. (Obesity journal, 2026)"
url: https://onlinelibrary.wiley.com/doi/10.1002/oby.70152
date: 2026-01-01
domain: health
secondary_domains: []
format: article
status: processed
processed_by: vida
processed_date: 2026-04-13
priority: high
tags: [glp1, racial-disparities, access-equity, medicaid, prescribing-disparities, health-equity]
extraction_model: "anthropic/claude-sonnet-4.5"
---

## Content

Retrospective pre-post study at a large tertiary care center examining GLP-1 prescribing disparities before and after a MassHealth (Massachusetts Medicaid) coverage change for obesity treatment (effective January 2024).

**Pre-coverage (before January 2024):**
- Black patients: 49% less likely to be prescribed semaglutide or tirzepatide vs. White patients (adjusted)
- Hispanic patients: 47% less likely vs. White patients (adjusted)
- Disparities were large and statistically significant

**Post-coverage change:**
- Disparities narrowed substantially after Medicaid expanded coverage
- Authors conclude: insurance policy is a primary driver of racial disparities, not provider bias alone

**Separate tirzepatide prescribing dataset (adjusted ORs vs. White patients):**
- American Indian/Alaska Native: 0.6
- Asian: 0.3
- Black: 0.7
- Hispanic: 0.4
- Native Hawaiian/Pacific Islander: 0.4

**Supplementary finding (wealth-based treatment timing):**
- Black patients with net worth >$1M: median BMI 35.0 at GLP-1 initiation
- Black patients with net worth <$10K: median BMI 39.4 (13% higher BMI at treatment start)
- Lower-income Black patients receive treatment further into disease progression — higher disease burden at access point

**Author conclusion:** Expanding insurance coverage (specifically Medicaid) substantially reduces racial disparities in GLP-1 prescribing. Policy change, not just provider education, is required.

## Agent Notes
**Why this matters:** This is the strongest causal evidence I've found that Medicaid coverage expansion is the primary lever for reducing GLP-1 racial disparities. The pre-post design with a natural experiment (coverage change) is methodologically stronger than observational cross-sectional studies. Combined with the state coverage retreat (16→13 states covering GLP-1 for obesity), this creates a coherent story: the policy instrument that reduces disparities is being withdrawn.

**What surprised me:** The magnitude — 49% lower likelihood for Black patients BEFORE coverage change. This is a very large disparity. And that disparities narrowed substantially AFTER coverage change suggests the disparity is primarily structural (coverage) rather than implicit bias. This is an important and somewhat counterintuitive finding — often disparities are attributed to provider behavior, but this data says coverage policy is the primary driver.

**What I expected but didn't find:** Evidence that the disparities FULLY closed after coverage expansion. "Narrowed substantially" suggests residual disparities remain — provider access, transportation, trust, and other structural factors still matter even with coverage.

**KB connections:**
- GLP-1 access infrastructure claims (Sessions 20-22)
- State Medicaid coverage retreat (16→13 states, Sessions 21-22)
- Social determinants of health / structural racism claims in the health domain

**Extraction hints:**
- Primary claim: "Racial disparities in GLP-1 prescribing (Black: 49% less likely, Hispanic: 47% less likely vs. White) narrowed substantially after Medicaid coverage expansion, identifying insurance policy as the primary structural driver — more than provider bias"
- Secondary claim: "Wealth-stratified treatment initiation timing for GLP-1s reveals an access-timing inversion: lowest-wealth Black patients present with BMI 39.4 vs. 35.0 for highest-wealth patients — receiving treatment further into disease progression"
- Both claims are rated LIKELY — pre-post design at one institution; needs replication for PROVEN

**Context:** This is a peer-reviewed study in Obesity, a major specialty journal. MassHealth's GLP-1 coverage expansion provides a natural experiment. Important caveat: this is a single tertiary care center in Massachusetts — may not generalize to other states or care settings.

## Curator Notes (structured handoff for extractor)
PRIMARY CONNECTION: GLP-1 access equity claims; structural racism in healthcare access
WHY ARCHIVED: Strongest methodological evidence found for the claim that insurance policy (not provider bias) is the primary driver of racial GLP-1 prescribing disparities; natural experiment design gives this causal leverage that cross-sectional studies lack
EXTRACTION HINT: Extract two separate claims — (1) the racial disparity magnitude and natural experiment result; (2) the wealth-stratified treatment timing finding. Keep them separate for atomic claim structure.
