GLP-1 medications accounted for 11.4 percent of total annual claims in 2025 for employers that cover them for weight loss, according to the International Foundation of Employee Benefit Plans. The question most employers are still working through is not whether to cover but which patients are most likely to benefit.
A new study released by the Health Transformation Alliance (HTA) addresses that question. HTA is an employer-owned healthcare purchasing coalition that, according to the organization, includes more than 85 US companies covering over five million lives. The analysis drew on Veradigm linked claims and Merative MarketScan, a large US commercial claims and electronic health record database, covering data from 2018 through 2025. The sample covered 12.7 million patients across two distinct populations: those with Type 2 diabetes, and those with obesity but no Type 2 diabetes. The study was observational, the models were internally validated by Merative, and long-term return on investment remains uncertain, as most results reflect approximately one year of follow-up.
The findings are specific enough to inform how self-insured employers and their advisors structure eligibility criteria, prior authorization requirements, and utilization management programs.
Among patients using GLP-1s for Type 2 diabetes, the study identified two distinct response profiles.The more effective group entered treatment with HbA1c, a measure of average blood sugar over roughly three months, above 8% and lower illness severity, measured by an average Charlson Comorbidity Index (CCI) of 1.9. They also had no emergency room or inpatient visits in the six months before starting therapy. In this group, HbA1c fell by 2.6 percentage points and average weight loss was 8.4 percent. Ninety-four percent remained on therapy for nine months or more.
The less effective group had higher comorbidity burden, with an average CCI of 2.1. They also had one or more ER visits or inpatient admissions in the six months before treatment. In this group, HbA1c increased by 0.1 percentage points and patients gained an average of 2.7 percent in body weight. Eighty-three percent remained on therapy for nine months or more.
The less effective group persisted on GLP-1 therapy at 83 percent, compared to 94 percent in the effective group, while receiving no measurable benefit on glycemic control or weight. For employers paying per prescription, that is a spend pattern that patient-level eligibility criteria could help address.
“If we can better understand who is likely to see a meaningful health benefit, employers can focus on getting the right treatment to the right people rather than treating every prescription the same,” said Rob Andrews, CEO of HTA.
Among patients with obesity but no Type 2 diabetes, the more effective group averaged 9.4% weight loss, with 84.5% achieving the clinical benchmark of 5% or more weight reduction. Eighty percent remained on therapy at nine months. Key distinguishing traits were a baseline weight of 175 to 299 pounds, age 44 or older, no sleep disorder, and fewer than three obesity-related prescription fills before treatment.
The less effective group averaged 5.3% weight loss, with 64.4% reaching the 5% threshold. Lower age and a starting weight below 175 or above 299 pounds were the distinguishing characteristics.
In both populations, patients with lower baseline disease complexity responded better. Eligibility criteria built around those characteristics could improve outcomes while limiting spend on patients the therapy is unlikely to help.
The advisory conversation around GLP-1s has already moved in this direction. Structured coverage with prior authorization and clinical eligibility requirements is now the model most employers are adopting with consultant guidance, as employer GLP-1 demand management coverage has documented. The HTA study provides population-level clinical data to anchor those criteria rather than relying on administrative proxies alone.
HTA notes that the study is not intended to predict individual outcomes or replace clinical judgment. Coverage criteria based on population-level data will not capture every individual case. For self-insured employers who need a defensible, evidence-based framework for GLP-1 decisions, the data offers a more grounded starting point than most plans currently have.
