Real-world evidence is what tells you whether a Phase 3 result holds up in routine care. Coverage on this site has leaned on Truveta's EHR network, IQVIA, and several academic registry analyses — particularly for GLP-1 outcomes outside trial conditions.
Key reads: the Truveta EHR analysis at OMA 2026 reproducing SURMOUNT-5's tirzepatide-vs-semaglutide signal at 12 months in routine care; the Mass General Brigham JAMA study of 90,000+ HFpEF patients on semaglutide and tirzepatide; the AAN 2026 living systematic review of GLP-1 dementia incidence in 2+ million diabetics; and the Foundayo IQVIA launch tracker through retail pharmacy.
Stories here cover the registry analyses, the Truveta and IQVIA data drops, and the policy implications. See #clinical-trial for trial-side coverage.
A separate ASCO 2026 analysis examined outcomes in patients with breast cancer and co-existing obesity or type 2 diabetes who received GLP-1 receptor agonists — adding breast-cancer-specific depth to the broader GLP-1-and-cancer signal that ran through the meeting. The analysis sits alongside Abstract 3143 (the 12,112-patient study showing 38-50% lower metastatic progression across four obesity-related cancers, with breast cancer at 10% vs 20% metastasis on GLP-1 vs gliptin) and the Roswell Park aggressive-breast-cancer analysis. The consistent theme across the ASCO 2026 GLP-1 oncology slate: in obesity-related and metabolically-driven cancers, GLP-1 therapy appears associated with better outcomes, with the strongest and most mechanistically interpretable signal in breast cancer where high tumor GLP-1 receptor expression tracked with 45% lower mortality. Adverse-event rates matched the comparator groups with no increase in pancreatitis or other GLP-1-associated concerns in the cancer setting. The data is observational and not yet RCT-grade, but the breast-cancer consistency across multiple independent analyses strengthens the case for prospective study.
Roswell Park Comprehensive Cancer Center will present an analysis at ASCO 2026 (May 29-June 2 Chicago) by Dr. Zunairah Shah on the effects of GLP-1 receptor agonists in aggressive breast cancer. The real-world study examines whether GLP-1 therapy — widely used for glucose control and weight loss — confers additional benefit in high-risk breast cancer outcomes. The analysis joins the broader ASCO 2026 GLP-1 oncology slate, which includes Abstract 3143 (the 12,112-patient analysis showing 38-50% lower metastatic progression across four obesity-related cancers, with breast cancer showing 10% vs 20% metastasis on GLP-1 vs gliptin and 45% lower mortality with high tumor GLP-1R expression). Roswell Park also presented a companion real-world analysis on protein-energy malnutrition outcomes in metastatic TNBC (Abstract 1135). The GLP-1-and-cancer signal is one of the most-watched emerging themes at ASCO 2026, expanding the GLP-1 indication conversation beyond cardiometabolic disease.
Novo Nordisk extended its EASL 2026 ESSENCE presentation cycle into Day 2 with real-world evidence quantifying the MASH disease burden — documenting significant quality-of-life impairment and escalating healthcare costs in MASH patients — alongside the Japanese MASH and menopausal women subgroup analyses presented Day 1. The data builds the health-economic case for semaglutide 2.4 mg following the August 2025 FDA MASH-with-fibrosis approval. MASH affects roughly 1 in 3 people living with overweight or obesity worldwide, with the majority undiagnosed. Novo's 'Love Your Liver' EASL initiative offered on-site MASH testing for attendees. The real-world burden data complements the ESSENCE Phase 3 efficacy story by establishing the economic and quality-of-life rationale for early MASH intervention — a payer-facing argument as the GLP-1 MASH indication scales into 2026-2027 against the THR-β, FGF21, and GLP-1/glucagon competitor classes.
A real-world data analysis previewed at ASCO's May 26 embargoed press briefing compared GLP-1 receptor agonists against DPP-4 inhibitors (gliptins) across 12,112 patients with seven obesity-related cancers. For four of the seven — lung, breast, colorectal, and liver — patients on GLP-1s were 38% to 50% less likely to progress to stage IV cancer than patients on gliptins. Specific metastasis rates: lung 10% (GLP-1) vs 22% (gliptin), breast 10% vs 20%, colorectal 13% vs 22%, liver 19% vs 28%. High tumor GLP-1 receptor expression was associated with a 33% lower risk of death across all seven cancer types; the association was particularly strong in breast cancer (45% lower mortality). The data reframes GLP-1 therapy as a candidate cancer-prevention modality alongside the established cardiometabolic indications. Abstract 3143 will be presented at the May 29-June 2 ASCO Annual Meeting in Chicago.
An ECO 2026 analysis covered May 18 by ScienceDaily examined 89,718 patients starting GLP-1 therapy — 75.6% semaglutide, 17.5% tirzepatide, 6.9% liraglutide — and stratified BMI change at year one. In the first year, 27% reduced BMI by less than 5%, 22.4% by 5-10%, 14.1% by 10-15%, and 15.8% by ≥15%, while 20.8% actually gained weight. Greater weight loss correlated with larger reductions in obesity-related risk endpoints; patients who gained weight after starting treatment faced worse health outcomes than untreated comparators in several measures.
A second post-hoc analysis of STEP UP presented Tuesday found Wegovy 7.2 mg delivered consistent weight loss across reproductive life stages: 22.6% premenopausal, 19.7% perimenopausal, 19.8% postmenopausal, with 41.4% of premenopausal women hitting ≥25% loss. Waist-circumference reductions: 17.5%, 15.6%, 15.3% respectively. Separately, a real-world analysis of 34,000+ women showed that those taking Wegovy had a 42-45% lower migraine risk and a 25% lower depression risk starting six months in versus those on menopausal hormone therapy alone. The real-world data lands as observational signals that warrant prospective study — not as proof of causation — but reinforces the cardiovascular and quality-of-life narrative for the women's-health subgroup.
Real-world data presented in the ECO 2026 cycle counters the trial-based efficacy headlines: a Prime Therapeutics commercial claims analysis (cited in the May 2026 Managed Healthcare Executive cover story) found just 8.1% of members persisted with anti-obesity GLP-1 medications for three years. A separate 6-month Medicaid persistence analysis showed roughly 61% staying on treatment at six months. The high attrition is driven primarily by GI tolerability, insurance turnover, and out-of-pocket costs after step-edit programs. For newer agents like semaglutide and tirzepatide, post-discontinuation weight regain averages 0.8 kg per month — projecting return to baseline by ~1.5 years. PBM programs (Optum Rx Weight Engage, Rightway, MedImpact GLP-1 Benefit 360) are now embedding multidisciplinary support to lift persistence above the current floor.
Prof. John Wilding (University of Liverpool) and colleagues will present at ECO 2026 a real-world observational study tracking obesity-linked complication rates by degree of GLP-1-driven weight loss. In the year following GLP-1 treatment initiation, 27.0% of patients had BMI reductions <5%, 22.4% had 5-<10%, 14.1% had 10-<15%, 15.8% had ≥15%, and 20.8% gained BMI. Over a mean 11-month follow-up, patients with ≥15% BMI reduction had 37% lower osteoarthritis odds, 30% lower CKD odds, 69% lower OSA odds, and 32% lower heart failure odds versus those with 0-5% reduction (all statistically significant except heart failure). Incidence per 1,000 person-years: 21.4 OA, 21.1 CKD, 20.3 OSA, 3.9 HF. The data quantifies the value of pushing for deeper weight loss rather than cruise-control dosing.
A Frontiers in Endocrinology multicenter retrospective cohort study (2026) reports real-world safety and effectiveness of semaglutide in patients with type 2 diabetes and end-stage renal disease — the population systematically excluded from FLOW (which capped at eGFR ≥ 25) and the SELECT pre-specified kidney composite analysis. ESRD patients comprise roughly 1% of the diabetic population but 7% of US healthcare spending; their cardiovascular event rates are among the highest documented. The cohort fills a clinical gap: prescribers managing dialysis-dependent patients have had to extrapolate from outcome trials that explicitly excluded the population. Work joins the SOUL oral-semaglutide CKD analysis as the fastest-growing GLP-1 evidence stream beyond obesity and T2D.
A presentation at the American Academy of Neurology 2026 meeting (closing April 22) reported that in 10,997 chronic migraine patients initiating GLP-1 agonists versus an equal topiramate cohort, GLP-1 users were 10% less likely to visit the ED (23.7% vs 26.4%), 14% less likely to be hospitalized, 42% less likely to start CGRP monoclonal antibodies, and 48% less likely to start valproate over 12 months — adding migraine to the growing list of GLP-1 secondary benefits.
A living systematic review presented at the American Academy of Neurology 2026 Annual Meeting integrating Phase 2/3 trials and real-world data from 2+ million individuals with diabetes found GLP-1 receptor agonist use was associated with a 20-35% lower incidence of dementia versus DPP-4 or SGLT2 inhibitors. Effect was strongest for semaglutide, despite the EVOKE Phase 3 Alzheimer's trial missing its cognitive endpoint.
A poster at the Obesity Medical Association annual conference (April 10-12, San Diego) showed tirzepatide achieved greater body weight reduction than semaglutide at 12 months in a real-world Truveta EHR analysis of adults with obesity without diabetes, consistent with SURMOUNT-5 clinical trial results.
Researchers analyzed 410,198 Reddit posts mentioning semaglutide or tirzepatide, finding 43.5% of 67,008 self-reported users described at least one side effect extending beyond clinical trial data.