Highlight
- Sleeve gastrectomy showed the highest probability (24.0%) of achieving clinically significant weight loss (≥20%) and normoglycemia (HbA1c <5.7%) after 1 year in obese adults with type 2 diabetes.
- Tirzepatide yielded superior outcomes (13.2%) compared to semaglutide (3.0%), indicating the potential advantage of dual GIP-GLP-1 receptor agonism over GLP-1 receptor agonist monotherapy.
- Emergency department visits and new gastrointestinal symptoms occurred more frequently following sleeve gastrectomy than with pharmacotherapy, underscoring the importance of safety monitoring.
- Real-world data analysis highlights the significant differences in baseline characteristics and potential residual confounding affecting outcome interpretation.
Study Background
The intertwined epidemics of type 2 diabetes mellitus (T2DM) and obesity pose a substantial global health burden, contributing to cardiovascular disease, nephropathy, retinopathy, and increased mortality risk. Contemporary therapeutic options include advanced pharmacotherapy—such as glucagon-like peptide-1 receptor agonists (GLP-1 RAs) and novel dual glucose-dependent insulinotropic polypeptide (GIP) and GLP-1 receptor agonists (titled incretin therapies)—as well as bariatric surgical interventions, notably sleeve gastrectomy. While randomized controlled trials have established efficacy for each modality, there remains a scarcity of direct, real-world comparative effectiveness data that integrate both weight and glycaemic outcomes across pharmacologic and surgical approaches in patients with severe obesity (BMI ≥35 kg/m2) and suboptimally controlled diabetes (HbA1c >6.4%). This retrospective cohort study seeks to fill this knowledge gap by leveraging a vast multicenter electronic health record dataset to inform clinical decision-making in diverse practice settings.
Study Design
This investigation used the Epic Cosmos electronic health record dataset, encompassing de-identified information from 1,633 hospitals and nearly 38,000 clinics across 280 US health systems, representing a broad real-world patient population. Inclusion criteria required adults with BMI ≥35 kg/m2 and baseline HbA1c above 6.4% initiating either semaglutide or tirzepatide therapy with maintenance dosing sustained for at least one year, or undergoing sleeve gastrectomy surgery. The index date was defined as treatment initiation or surgery date. The primary composite endpoint assessed at 1 year (within a 9-15 month window) was achievement of at least 20% weight loss combined with an HbA1c below 5.7%, reflecting both substantial obesity reduction and remission-level glycaemic control.
Multivariate logistic regression modeling adjusted for potential confounders including age, sex, race, baseline HbA1c, baseline BMI, Charlson Comorbidity Index, Social Vulnerability Index (SVI), and baseline medication use for diabetes, lipid disorders, and hypertension. Safety outcomes focused on the frequency of emergency department visits and initiation of medications for new-onset gastro-oesophageal reflux disease (GERD) or nausea within 1 year.
Key Findings
After applying eligibility filters and addressing missing data, the analytic cohort included 45,093 patients: 33,482 treated with semaglutide, 4,178 with tirzepatide, and 7,433 undergoing sleeve gastrectomy. Baseline differences were notable: the surgical group had higher BMI, younger age, and lower baseline HbA1c compared to pharmacotherapy groups.
| Outcome | Semaglutide (n=33,482) | Tirzepatide (n=4,178) | Sleeve Gastrectomy (n=7,433) |
|---|---|---|---|
| Probability of ≥20% weight loss and HbA1c <5.7% at 1 year (adjusted) | 3.0% (95% CI 2.8–3.2) | 13.2% (12.2–14.3) | 24.0% (22.9–25.1) |
| Emergency Department Visits within 1 year | Fewer than surgery (exact % not specified) | Fewer than surgery (exact % not specified) | Highest rate observed (relative to pharmacotherapy) |
| New prescriptions for GERD or nausea | Present, lower frequency than surgery | Present, lower frequency than surgery | Highest frequency among groups |
The surgical cohort’s superior combined outcome likely reflects the substantial and sustained weight loss achieved via anatomical and physiological modifications from sleeve gastrectomy, promoting improved insulin sensitivity and beta-cell function. Tirzepatide, a dual GIP and GLP-1 receptor agonist, demonstrated improved efficacy over semaglutide (a GLP-1 RA alone), consistent with emerging evidence supporting additive incretin effects on weight and glycaemic regulation.
Regarding safety, higher emergency department utilization and gastrointestinal symptoms in the sleeve gastrectomy group emphasize the invasive nature and postoperative complications intrinsic to surgery. The pharmacotherapy groups had lower rates of acute adverse events but did experience gastrointestinal side effects, consistent with known GLP-1 RA profiles.
Expert Commentary
This large-scale real-world investigation offers valuable comparative data for clinicians managing patients with obesity and T2DM, reinforcing the potent metabolic benefits of bariatric surgery while contextualizing the evolving role of incretin-based therapies. Notably, the study’s retrospective design and baseline heterogeneity, including younger and less comorbid patients undergoing surgery, may introduce residual confounding and limit direct causal inference.
Moreover, the relatively low absolute rates of achieving the composite endpoint with pharmacotherapies underscore an unmet need for more effective or combination strategies in routine practice. Future prospective trials and longer-term data are warranted to assess durability, cardiovascular outcomes, and quality of life measures.
Conclusion
At 1 year, sleeve gastrectomy remains the most effective intervention for achieving substantial weight loss and near-normoglycemia in adults with obesity and type 2 diabetes, albeit with higher acute healthcare utilization and gastrointestinal symptoms. Tirzepatide shows promising improved efficacy compared to semaglutide, marking it as a compelling pharmacologic option. Individualized treatment decisions should weigh efficacy, patient characteristics, safety profiles, and long-term outcomes to optimize obesity and diabetes care.
Funding and ClinicalTrials.gov
This study was conducted without external funding. No ClinicalTrials.gov identifier is available for this retrospective cohort analysis.
References
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- Frias JP, Bastyr EJ, Vignati L, et al. Efficacy and Safety of Tirzepatide Monotherapy in Subjects with Type 2 Diabetes. Diabetes Care. 2021;44(6):1443–1451.
- Schauer PR, Bhatt DL, Kirwan JP, et al. Bariatric Surgery versus Intensive Medical Therapy for Diabetes — 5-Year Outcomes. N Engl J Med. 2017;376(7):641–651.
- Koliaki C, Liatis S, Dalamaga M, et al. Bariatric surgery and cardiovascular risk: a systematic review and meta-analysis. J Clin Endocrinol Metab. 2021;106(7):e2656–e2669.