Coverage arguments usually assume that people who qualify get treated. A retrospective study using every Medicare fee-for-service claim for 2023 and 2024 shows the distance between those two things, and it is wide [1]. It is the older-age counterpart to the national picture in who the price filtered out.
Across Medicare fee-for-service beneficiaries with Part D coverage (n = 16,474,786), 6.2% had a claim for one of these drugs. A much larger group, 35.1%, already carried a condition Medicare covers them for — type 2 diabetes, established cardiovascular disease with overweight or obesity, obstructive sleep apnea with obesity, or metabolic dysfunction-associated steatohepatitis.
A separate 1.2 million beneficiaries, about 7%, had obesity and nothing else that qualifies. Their exclusion is statutory rather than a plan's decision, because Medicare Part D has long been barred from covering a drug prescribed for weight alone. That is why the route to coverage for so many people runs through a second diagnosis, and why the study counts potential future indications at all: 76.9% had at least one current or possible future qualifying condition.
The authors then model what would change if Medicare covered heart failure with preserved ejection fraction, chronic kidney disease, psoriasis or knee osteoarthritis. About 35% of the currently ineligible group, some 407,085 people, would qualify. That is a conditional estimate rather than a forecast, and given the 16.5% figure above it, an expansion of eligibility would be expected to move actual treatment by a good deal less.
For a cash market this is the demand picture in one number. A population with covered access that mostly is not using it is a population still deciding on grounds other than coverage — cost-sharing, supply, tolerability, or simply never being offered it — which is why the published price remains the operative figure for so many buyers. What that price looks like across the market is in what a GLP-1 actually costs, what insurance does to it in what coverage costs, and what happens to a national bill when a country covers it for everyone in does national coverage cost more.