Aon's 50-Million-Person GLP-1 Dataset Prices the Employer Coverage Gap

Aon's analysis of more than 50 million commercial lives found GLP-1-treated Type 2 diabetics had 30-month medical cost growth 6 percentage points lower than untreated peers, widening to 9 points among members with 80% or greater adherence. IFEBP's 2026 survey, released the same year, shows employer coverage for weight loss frozen at 36%.

Two datasets, one pointing at a multi-year offset and the other at a one-year decision. The arithmetic that reconciles them is a dollar figure neither report publishes.

Key Takeaways

• 6 percentage points of lower 30-month cost growth for treated diabetics, widening to 9 points at 80% adherence, are growth-rate differentials rather than dollars. Converting them needs an excess-cost base neither report supplies.
• $7,482 is the ADA's average annual excess medical expenditure for a diagnosed diabetic under 65. Run at an 8% trend it compounds roughly 21.7% over 30 months, about $1,623 per untreated member.
• $1.1 million to $1.4 million of annual net drug cost for 150 treated members in a 5,000-life group, against roughly $40,000 a year of avoided cost growth. On growth alone the offset loses by an order of magnitude.
• $19,642 is the mean initial cost of a cardiovascular hospitalization, 12 to 29 times the per-member avoided growth. The lumpy half of the offset is what moves the crossover year, not the smooth half.

What the Two Datasets Say

Aon's second-phase release expanded its May 2025 analysis to 192,000 GLP-1 users drawn from a de-identified pool of more than 50 million commercial medical and pharmacy claims running July 2022 through March 2025. Members with a Type 2 diabetes diagnosis on sustained therapy showed medical cost growth 6 percentage points lower than untreated diabetic peers at 30 months, widening to 9 points at 80% or greater adherence. Weight-loss users without a diabetes diagnosis showed 3 points lower at 18 months, improving to 7 with consistent use.

Those are growth-rate differentials, not absolute dollars, and converting them needs a base. The American Diabetes Association puts average annual excess medical expenditure for a diagnosed diabetic under 65 at $7,482 against a demographically matched member without diabetes, with spending running 2.6 times what would otherwise be expected.

IFEBP's 2026 Pulse Survey, covering roughly 300 employer health plans, found combined diabetes-and-weight-loss coverage held at 36% for a second straight year, up from 34% in 2024 and 26% in 2023. Diabetes-only coverage climbed to 60% from 55%, and 45% of plans now cover other FDA-approved indications. The class reached 11.4% of annual claims in 2026, up from 6.9% in 2023.

Carey Wooton, CEBS, IFEBP's associate vice president of education, described the posture: "Most employers are not covering GLP-1 drugs for weight loss but instead focusing on how to support the overall health of their workers" (IFEBP, July 2026).

Where the Offset Lands in Dollars

Converting Aon's percentage points into a group's actual claims line puts the near-term answer and the multi-year answer in different places.

Apply a representative 8% annual group medical trend to the ADA excess-cost base and it compounds to roughly 21.7% growth over 30 months, an increase of about $1,623 per untreated diabetic member. A member at 80%-plus adherence, growing 9 points slower, sees that base climb closer to 12.7%, about $952, a difference of roughly $671. At the 6-point real-world offset the avoided growth narrows to about $450. Neither figure is Aon's own; both apply Aon's offset to the ADA baseline, and a plan actuary should substitute the group's own diabetic claims experience.

Scale that to a 5,000-life employer with 10% diabetes prevalence, 500 diabetic members, of whom 30% take up therapy at high adherence, so 150 members. Avoided cost growth comes to roughly $100,650 over 30 months, about $40,000 a year. Net drug cost for those same 150 members runs $617 to $766 per month per person after manufacturer rebates (EBRI, October 2025), or $1.1 million to $1.4 million annually.

The growth differential is not the whole offset. Aon's diabetic cohort showed major adverse cardiovascular event reductions of 47% among women and 26% among men at high adherence, plus roughly 50% lower ovarian cancer incidence and 14% lower breast cancer incidence among female users. A single avoided cardiovascular hospitalization carries a mean initial cost of $19,642, some 12 to 29 times the $671-to-$1,623 range of avoided growth per treated member.

Priced as two cohorts on two clocks rather than one blended trend load, the crossover where cumulative avoided claims approach cumulative drug spend lands in year three to year four of continuous, high-adherence therapy. There is no ADA-equivalent public excess-cost baseline for obesity absent a diabetes diagnosis, which is why the second column below has to be built from a sponsor's own claims history.

Persistence Is the Assumption That Breaks

A year-three crossover only pays if members are still on therapy in year three, and that is the assumption carrying the least support.

Roughly two in three GLP-1 users come off therapy before 12 weeks in prior real-world data, and discontinuation concentrates in the weight-management cohort, whose offset accrues latest and smallest. A year-three crossover also sits close to typical employee tenure once turnover and plan switching are counted, so a sponsor pricing one 12-month renewal rarely captures the inversion.

Two oral entrants change the mix rather than the price. Novo Nordisk's once-daily oral semaglutide, approved in December 2025, produced 16.6% mean weight loss in the OASIS 4 trial, comparable to injectable Wegovy at the 2.4 mg dose. Eli Lilly's Foundayo ran closer to 11% at its highest 17.2 mg dose over 72 weeks, against injectable Zepbound's roughly 20.9% at its top 15 mg dose. Both list near $1,050 to $1,060 per month, the same range as injectable list pricing.

A pill removes the injection-related discontinuation drivers while attracting a milder-severity population willing to accept a smaller efficacy result for convenience. Average adherence and average clinical benefit can therefore move in opposite directions at the same time, so neither the injectable adherence curve nor the injectable offset percentages carry over unchanged into an oral-inclusive model.

The cheaper channel is closing alongside. On April 30, 2026 the FDA proposed excluding semaglutide, tirzepatide and liraglutide from the Section 503B bulks list, citing more than 455 adverse event reports linked to compounded semaglutide and over 320 tied to compounded tirzepatide; the comment period closed June 29. Compounded product had been the lower-cost access valve for plans and stop-loss carriers managing exposure without full formulary coverage, and its removal pushes utilization toward full-price branded product.