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.
Researchers at Chi Mei Medical Center in Taiwan reported in Diabetology & Metabolic Syndrome on October 13, 2026 a records study in the TriNetX U.S. network that matched 176,981 women with overweight or obesity who started tirzepatide between 2022 and 2025 with the same number in lifestyle programs. Over up to two years, tirzepatide users had a lower rate of new endometrial cancer diagnoses (hazard ratio 0.717), a pattern seen across most subgroups. The authors said the observational, short-term findings do not establish that tirzepatide prevents the cancer.
Researchers at IRCCS Istituto Auxologico Italiano and the University of Milan reported in Frontiers in Endocrinology on October 12, 2026 a retrospective study of 120 adults with obesity, 67 given semaglutide with a reduced-calorie diet and 53 the diet alone. At six months the semaglutide group lost 3.3 kg more, with similar gaps in people who reported strong food cravings (3.1 kg) and those who did not (3.4 kg). The study was small, not randomized, and lasted six months.
Researchers at Chi Mei Medical Center in Taiwan reported in Frontiers in Pharmacology on October 9, 2026 a TriNetX records study of adults with both COPD and type 2 diabetes, matching tirzepatide users one-to-one with users of other diabetes drugs. Compared with 6,080 matched SGLT2 inhibitor users, tirzepatide was associated with fewer COPD flare-ups (hazard ratio 0.73) and lower death rates (0.30), with similar results against DPP-4 inhibitors; against other GLP-1 drugs, flare-up rates were similar. Tirzepatide users were followed for a median of about 233 days versus 365 for the comparison groups, and the size of the mortality gap suggests that differences between the groups, not only the drug, may be at work.
A UT Southwestern study published October 7, 2026 in Diabetes, Obesity and Metabolism compared 73,592 matched pairs of veterans with type 2 diabetes who started a GLP-1 drug or a DPP-4 inhibitor, an older diabetes pill, between 2006 and 2021. Over about 27 months, the GLP-1 group had a 13% lower fall rate (incidence rate ratio 0.87) and slightly less worsening on a frailty index. The link weakened in people who were already severely frail, and the observational design cannot prove the drugs caused the difference.
Researchers at Hebrew University and Hadassah Medical Center reported in Diabetes, Obesity and Metabolism on October 7, 2026 a records study of 4,554 matched adults with type 2 diabetes and stage 3 or 4 chronic kidney disease who started a GLP-1 drug or tirzepatide, or finerenone, a non-steroidal kidney drug. Kidney failure or dialysis occurred in 4.8% versus 6.0% within 2.5 years (hazard ratio 0.71), but the absolute risk difference of 1.14 percentage points was not statistically clear. Albuminuria, a key kidney measure, was missing for most people, so the authors warned of residual confounding.
University of Pennsylvania researchers reported in JAMA Network Open on October 7, 2026 that among 47.9 million adults eligible for obesity medicines in Epic Cosmos, a database of health records from more than 2,000 U.S. hospitals, 148,792 started oral semaglutide between December 22, 2025, when the FDA approved the pill for obesity, and March 15, 2026: 87.6% on the Wegovy pill and 12.4% on Rybelsus. Weekly starts peaked at 4.56 per 10,000 eligible adults in early March, briefly exceeding starts of injectable semaglutide, and 53.0% of people starting the pill had never used a GLP-1 drug before. Compared with people starting injections, pill users were older on average, more often women (72.7%), and had a lower average BMI (36.6); the study counted prescription orders, which may not all have been filled.
A retrospective study from two centers in Palermo, Italy, published online September 25, 2026 in the Journal of Diabetes and Its Complications and reported by News-Medical on October 2, followed 122 adults with overweight or obesity and no diabetes who took tirzepatide alongside a standardized low-carbohydrate diet and tailored exercise. After 24 weeks, at a mean final dose of 5.32 mg, average weight fell from 95 kg to 80 kg, fat mass fell 35.4% and fat-free mass 5.1% on bioelectrical impedance, and the authors reported that skeletal muscle was preserved. The study had no control group, used bioimpedance rather than DXA scans, and included only people who completed the 24 weeks.
A retrospective study from Taipei Medical University, published in BMC Gastroenterology on Saturday, October 3, 2026, used the U.S. TriNetX health records network to compare 4,870 adults with type 2 diabetes who had a GLP-1 receptor agonist prescription in the three months before a colonoscopy with 4,870 matched adults who did not. Within 12 months, 11.0% of GLP-1 users had a repeat colonoscopy versus 8.9% of nonusers (hazard ratio 1.37), and the gap was similar after June 2023 society guidance on holding the drugs before procedures. The authors used a repeat colonoscopy as a stand-in for poor bowel preparation, which the study did not measure directly, and described the absolute difference as modest.
Novo presented at EASD on Wednesday, September 30, 2026 OCTANE, a retrospective analysis of de-identified data from the telehealth company Ro covering 194 adults who switched from injectable semaglutide or tirzepatide to the once-daily Wegovy pill between January 5 and February 7, 2026. From a mean baseline weight of 100.5 kg and BMI of 34.5, participants lost an average of 4.1% of body weight (4.0 kg) over three months, 40.7% lost at least 5%, and the share with a BMI of 30 or higher fell from 87.1% to 65.5%. Novo listed limitations including self-reported and incomplete data and selection bias from counting only people who stayed on treatment; the release did not give the injectable doses people switched from.
Novo announced on Tuesday, September 29, 2026 results of COMPETE SWITCH CV, a retrospective analysis of U.S. claims data from Komodo Health (January 2018 to September 2025) in adults with type 2 diabetes who had been taking semaglutide 1 mg. Over up to 720 days, the 185,705 people who escalated to semaglutide 2 mg had a 6% lower adjusted risk of death, heart attack, or stroke than the 23,104 who switched to tirzepatide (adjusted hazard ratio for switching 1.06; 95% CI 1.04 to 1.08). Novo said the analysis shows an association rather than cause and effect, may carry residual confounding, and did not assess safety outcomes.
Healthline reported on Friday, September 18, 2026 on a study by nference researchers, including Venky Soundararajan, published August 31 in Biology Methods & Protocols. The study followed 1,016 people who stayed on 2.5 mg tirzepatide for at least six months and 814 who took at least three 0.25 mg semaglutide doses over at least six months; at 12 months, weight loss averaged about 5.5% and 2.2%, respectively. At 24 months, people on sustained low-dose semaglutide had lower rates of constipation (23.3% vs 36.3%), nausea (39.7% vs 50.1%), and low blood pressure (1.7% vs 5.4%) than people on higher doses. Mir Ali, MD, of MemorialCare told Healthline that most patients will need some dose escalation to keep losing weight, and the article noted that dosing outside approved schedules is not FDA- or manufacturer-approved.
Real-world evidence for Wegovy (semaglutide 2.4 mg once weekly subcutaneous injection) documents 5.9% to 12% mean body weight reduction at 6 to 12 months across registry and claims analyses. This compares to 14.9% weight loss in the STEP-1 registrational trial that supported the FDA approval. The gap is primarily adherence-driven: missed doses, titration pauses, insurance-driven dose changes, and stop-restart cycles flatten real-world curves relative to the tight-adherence STEP-1 population. Cleveland Clinic research confirmed that injectable obesity medications produce smaller weight loss in a real-world setting compared to randomized clinical trials, with the gap larger in patient subgroups facing financial barriers to consistent supply. A large real-world study of nearly 8,000 patients who discontinued GLP-1 therapy found that most manage to keep the weight off or continue losing by restarting treatment, switching medications (typically to tirzepatide or higher-dose Wegovy), or adopting lifestyle changes. Patient satisfaction is driven primarily by perceived effectiveness rather than tolerability: effective weight loss even with gastrointestinal side effects is associated with continued treatment adherence, while lower-efficacy responses lead to early discontinuation regardless of tolerability. The real-world evidence has implications for retatrutide's likely commercial trajectory: the 28.3% TRIUMPH-1 result may translate to 15-20% in real-world use depending on adherence patterns, which is still substantially above semaglutide's real-world 5.9-12% range.
A CROI 2026 (Conference on Retroviruses and Opportunistic Infections) analysis presented earlier in 2026 documented that GLP-1 weight-loss medications generally work well for people living with HIV who are stable on antiretroviral therapy. Beyond the known obesity and type 2 diabetes benefits, the CROI analysis reported potential improvements in liver, gut, and cardiovascular health, plus reduced smoking rates in the HIV population on GLP-1 therapy. Real-world analysis of people living with HIV prescribed semaglutide (Wegovy, Ozempic) or tirzepatide (Mounjaro, Zepbound) documented comparable weight loss to general-population Phase 3 trial data with no new safety signals specific to the HIV population. Approximately 40% of people living with HIV in the US also have obesity, and cardiovascular disease is one of the primary drivers of morbidity and mortality in the HIV-treated population. The CROI analysis supports GLP-1 therapy as a reasonable consideration in HIV patients with obesity or metabolic-syndrome comorbidities, particularly following the AIDS 2026 conference programming that concluded Friday July 31 in Rio de Janeiro emphasizing the sustained management of HIV alongside comorbid conditions in the current global funding-constrained environment. The finding also intersects with the ongoing peptide-adjacent HIV therapeutic landscape covered by the July 2026 Gilead-Merck ISLEND-1 and ISLEND-2 once-weekly islatravir/lenacapavir data and the Merck alimatravir monthly HIV prevention pill.
US data-analytics firm nference published a real-world evidence analysis this week that compared frailty-related outcomes across three cohorts of US adults 65 and older: nearly 30,000 patients treated with Zepbound (tirzepatide) for obesity, nearly 19,000 receiving non-GLP-1 drugs for type 2 diabetes, and nearly 6,000 who underwent weight-loss surgery. Health records showed progressive declines in muscle mass and function developed in 0.16% of patients across the analysis, malnutrition in 1.6%, dehydration in 3%, and loss of appetite in 4.75%. Lead author Soundararajan's team focused on Zepbound because prior analyses linked tirzepatide with more weight and muscle loss than semaglutide (the active ingredient in Novo Nordisk's Wegovy and Ozempic). The authors said results should not discourage appropriate use of Zepbound or Wegovy in older adults and encouraged closer follow-up of older patients on GLP-1 therapy. The findings arrive as the Medicare GLP-1 Bridge (launched July 1, 2026) expands GLP-1 access to Part D beneficiaries and as prescribers weigh muscle-preservation strategies including selective androgen receptor modulators (SARMs) like Veru's enobosarm and myostatin inhibitors.
Eisai and Biogen announced Tuesday July 14, 2026 that data from the real-world Lecanemab in Early Alzheimer's Disease (LEADER) Study, presented at AAIC 2026 in London during the Developing Topics Session '#3-33-DEV-A: Lecanemab Three Years Post-Approval: A Comprehensive Multicenter, Real-World, Retrospective Study (LEADER) in Diverse US Clinical Settings,' documented durable clinical outcomes with LEQEMBI in early Alzheimer's disease. The analysis included 432 early Alzheimer's disease patients from diverse US clinical settings who had received at least seven LEQEMBI infusions as of May 2026. Over an average of 17 months of treatment, 75.9% of patients remained clinically stable and 6.6% improved (moving from mild Alzheimer's disease dementia to mild cognitive impairment due to Alzheimer's disease). 87% of patients chose to remain on LEQEMBI treatment. Results were consistent across sex, race, ethnicity, and APOE genotype, supporting long-term benefits of continuous treatment outside of a controlled clinical trial setting.
The Conference on Retroviruses and Opportunistic Infections (CROI 2026, March 9-12) featured an oral plenary by Dr. Todd Brown of Johns Hopkins Medicine titled 'GLP-1 Agonists: Are They a Cure for Everything?' alongside one oral abstract and seven posters on the use of GLP-1 receptor agonists in people living with HIV (PLWH). The findings: GLP-1s generally work well in PLWH, may improve liver fibrosis, gut tissue immune health, and cardiovascular risk, and may reduce smoking on top of the established weight loss and diabetes effects. One oral abstract suggested potential to reverse the gut damage that persists from very early HIV infection despite effective ART. Brown's plenary concluded the enthusiasm is warranted but flagged unanswered questions around long-term use and global access — particularly relevant for PLWH in low- and middle-income countries.
An analysis of 60,000+ Americans with type 2 diabetes, presented at ENDO 2026 by Sainikhil Sontha (Boston University School of Public Health) and published in the Endocrine Society press release stream, found that 40% of GLP-1 users discontinued the medication within 12 months and roughly 60% had stopped by the end of two years. Among those who stopped, 41.5% restarted within a year and 58% within two years. Discontinuation was higher among Medicaid/Medicare beneficiaries, Black patients, and patients with documented nausea or GI side effects (37% of stoppers). Newer-generation tirzepatide users were 41% less likely to discontinue than liraglutide users, and patients whose first GLP-1 was prescribed by an endocrinologist were 10% less likely to stop. The data complement the Cleveland Clinic 8,000-patient real-world finding (March) and the eClinicalMedicine Budini meta-regression on weight-regain trajectory, sharpening the picture of how GLP-1 therapy churn actually unfolds in US insurance-claims populations.
A real-world comparison of tirzepatide and semaglutide for obesity by Venkatakrishnan and colleagues, published in PNAS Nexus on June 16, reported mean body-weight reductions of 14.7% on tirzepatide versus 10.8% on semaglutide at one year. The tirzepatide arm produced close to twice the proportion of 'high responders' (more than 15% body-weight loss) and lower rates of GI events, headache, and fatigue. Female and white patients responded more strongly on either drug than male, black, or Hispanic patients, who were more frequently in the under-5% weight-loss tier. The findings track with SURMOUNT-5's head-to-head trial result and the April 13 OMA Truveta poster but add a new demographic-disparity dimension that should inform real-world treatment selection.