The SELECT Trial Should Have Cardiologists Prescribing Semaglutide. Most Are Not.

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The evidence base

The SELECT trial enrolled 17,604 adults with a BMI of 27 or greater, established atherosclerotic cardiovascular disease, and no history of diabetes. This is not a metabolic subgroup enrichment. This is a large, clean, cardiovascular outcomes trial. Lincoff et al., NEJM 2023 reported that patients randomized to weekly subcutaneous semaglutide 2.4 mg experienced a 20% relative risk reduction in the composite of cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke compared with placebo (HR 0.80 to 95% CI 0.72 to 0.90, P < 0.001). The trial ran for a median of 34.2 months. The absolute risk reduction was 1.5 percentage points. Number needed to treat: approximately 67 over three years.

That NNT compares favorably with several secondary prevention standards cardiologists already prescribe without hesitation. High-intensity statin therapy in a comparable post-MI population yields NNTs in the range of 40 to 80 depending on baseline risk and trial. Ezetimibe added to statin therapy in IMPROVE-IT produced an NNT of approximately 50 over seven years. Semaglutide's 67 over three years is not miraculous. It is, however, squarely in the territory of drugs that get written on discharge prescriptions.

Critically, the cardiovascular benefit in SELECT was independent of the degree of weight loss achieved. As Lincoff and colleagues noted, the MACE reduction emerged well before the plateau of weight reduction, and mediation analyses attributed only a portion of the benefit to weight change itself. The implication is that semaglutide is not simply acting as a "get the patient thinner" intervention. There are plausible direct anti-inflammatory and anti-atherosclerotic mechanisms under active investigation, including reductions in C-reactive protein and effects on macrophage function in plaque.

The FDA responded to SELECT with the first-ever approval of a weight-management drug specifically for cardiovascular risk reduction. In March 2024, the FDA expanded Wegovy's indication to include reducing the risk of serious cardiovascular events in adults with established cardiovascular disease and either obesity or overweight. This was not a label update buried in fine print. It was a new primary indication category, distinct from weight loss.

The background against which this trial lands matters. The 2021 AHA Scientific Statement on Obesity and Cardiovascular Disease concluded that "obesity is a causal risk factor for CVD," reviewing evidence that excess adiposity drives dyslipidemia, hypertension, insulin resistance, systemic inflammation, and adverse cardiac remodeling through mechanisms that operate even when traditional risk factors appear controlled. The statement called for obesity to be treated as a cardiovascular diagnosis, not an adjacent lifestyle variable. SELECT operationalized that framing with a hard endpoint trial. The AHA statement and SELECT together close a logical loop that cardiology has been slow to act on.

What the data does and does not show

SELECT does not tell us whether semaglutide outperforms optimized medical therapy plus intensive lifestyle intervention in a well-resourced setting. That trial has not been done. The placebo arm in SELECT was on background secondary prevention therapy, which is the correct design, but it means the 20% RRR is additive to, not a replacement for, statins, antiplatelets, and renin-angiotensin blockade.

The trial population was 72% male and predominantly white, which limits how confidently we can generalize the NNT to populations with different baseline risk profiles. Women, who were underrepresented, may have different absolute benefit calculations. Subgroup analyses by sex showed consistent directional benefit but wider confidence intervals. We consider this a real limitation, not a dismissal of the overall result.

SELECT also did not have an active comparator arm. We do not know how semaglutide compares head-to-head with SGLT2 inhibitors or icosapentaenoic acid (as in REDUCE-IT, Bhatt et al., NEJM 2019) in an overlapping population. Some SELECT-eligible patients are already on empagliflozin or dapagliflozin for heart failure or CKD indications based on the EMPEROR-Reduced and DAPA-HF trial findings (Packer et al., NEJM 2020; McMurray et al., NEJM 2019). Whether semaglutide is additive, synergistic, or partially redundant in those patients is genuinely unknown. We are extending judgment here: we believe the mechanisms are sufficiently distinct that additive benefit is plausible, but we will say plainly that this is reasoning from mechanism, not from trial data.

Gastrointestinal tolerability is a real-world friction point SELECT does not resolve. Approximately 10% of patients in the semaglutide arm discontinued the drug, primarily for GI adverse effects. Nausea affected roughly 44% of the semaglutide group versus 16% in placebo. In a post-MI patient who is deconditioned, nauseated, and managing a polypharmacy burden, titration requires active clinical management. That is not a reason to withhold the drug. It is a reason to assign it to a prescriber who will follow the titration.

The cost and access question is also not resolved by the trial. Wegovy listed at over $1,300 per month in the US as of mid-2024. Insurance coverage for the cardiovascular indication is inconsistent. Medicare Part D's coverage expansion under the Inflation Reduction Act framework has moved slowly. We are not dismissing these barriers. We are arguing that they are implementation problems, not evidence problems.

Our position

The HealthRX Medical Team holds this position: semaglutide 2.4 mg weekly should be considered standard secondary prevention therapy for adults with established atherosclerotic cardiovascular disease and a BMI of 27 or greater who are not already taking a GLP-1 receptor agonist, absent specific contraindications. This should be initiated and managed by cardiologists, not deferred to endocrinology by default.

The reasoning chain is as follows. SELECT met its primary endpoint in a large, well-powered cardiovascular outcomes trial with a hard composite. Lincoff et al. showed an HR of 0.80 with a tight confidence interval that excludes no benefit. The FDA has granted an indication specifically for MACE prevention in this population. The AHA scientific statement established the mechanistic and epidemiological rationale for treating obesity as a direct cardiac risk factor. The NNT is competitive with established secondary prevention agents. The risk profile is manageable with proper titration. There is no credible evidence argument for withholding this drug from the indicated population while you wait for a head-to-head comparator trial.

The prevailing clinical behavior, deferring semaglutide prescribing to endocrinology or obesity medicine, reflects a category error. Cardiologists do not defer statins because lipidologists exist. They do not defer antiplatelet therapy because hematologists understand platelet biology more deeply. The same logic applies here. The SELECT population is a cardiology population. The indication is cardiovascular. The prescribing should reflect that.

This does not mean cardiologists must manage every aspect of weight-related care. Multi-specialty coordination remains appropriate for complex cases. But waiting for an endocrinology referral to complete before initiating semaglutide in a post-ACS patient with a BMI of 32 is a delay that SELECT does not justify.

We acknowledge two places where we are going beyond strict trial support. First, we are recommending workflow integration in cardiology practices before formal cardiology society guidelines have mandated it. The ACC/AHA 2023 guideline on chronic coronary disease acknowledges GLP-1 receptor agonists in the context of diabetes but does not yet carry SELECT's non-diabetes population into a class I recommendation. We expect that to change in the next revision. Second, we are making a prescribing-authority argument based on SELECT's population characteristics rather than a randomized comparison of outcomes by prescriber type. Prescriber-type RCTs don't exist and won't be done. Our recommendation here is judgment.

Cardiologists who see 20 high-risk post-MI patients per clinic day and prescribe high-intensity statins, dual antiplatelets, and ACE inhibitors for all of them should be reviewing each chart for SELECT eligibility the same way they review LDL targets. This requires adding BMI to the secondary prevention checklist. It requires a titration protocol and a nurse or APP who owns follow-up calls during the dose-escalation phase. It requires prior authorization workflows that the practice can run efficiently. None of this is impossible. It is a workflow build that has not happened in most practices because the drug was categorized as belonging to someone else.

What would change our mind

Several findings would cause us to walk back or significantly qualify this position.

A well-powered head-to-head trial showing that semaglutide does not reduce MACE when added to optimized contemporary therapy (including newer lipid-lowering agents like inclisiran or bempedoic acid) would revise our NNT estimates meaningfully downward. We would then apply more selective criteria. Data from ongoing mechanistic substudy analyses of SELECT suggesting the MACE benefit is primarily mediated by weight loss, rather than direct vascular effects, would make patient selection more risk-stratified and would reduce the urgency for patients achieving less weight reduction. A significantly higher rate of serious adverse events in real-world pharmacovigilance data, including medullary thyroid carcinoma signals that the FDA has monitored since semaglutide's initial approval, would require a benefit-risk recalculation by baseline CVD severity. And if SGLT2 inhibitor combination data from trials currently in design showed that patients already on empagliflozin-plus-semaglutide achieve no additional MACE reduction over empagliflozin alone, cardiologists would need to triage the two agents differently rather than layer them reflexively.

Until any of that evidence arrives, the gap between what SELECT showed and what cardiology practices are doing is not a nuanced clinical disagreement. It is a lag.

Frequently asked questions

References

  • Lincoff AM, et al. Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes. N Engl J Med. 2023;389(24):2221-2232. https://pubmed.ncbi.nlm.nih.gov/37952131/
  • FDA News Release. FDA Approves First Treatment to Reduce Risk of Serious Heart Problems Specifically in Adults with Obesity or Overweight. March 2024. https://www.fda.gov/news-events/press-announcements/fda-approves-first-treatment-reduce-risk-serious-heart-problems-specifically-adults-obesity-or
  • Lilly LS, et al. (Writing Committee). AHA Scientific Statement: Obesity and Cardiovascular Disease. Circulation. 2021;143(21):e984-e1010. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000973
  • Bhatt DL, et al. Cardiovascular Risk Reduction with Icosapentaenoic Acid for Hypertriglyceridemia (REDUCE-IT). N Engl J Med. 2019;380(1):11-22. https://pubmed.ncbi.nlm.nih.gov/30415628/
  • Packer M, et al. Cardiovascular and Renal Outcomes with Empagliflozin in Heart Failure (EMPEROR-Reduced). N Engl J Med. 2020;383(15):1413-1424. https://pubmed.ncbi.nlm.nih.gov/32865377/
  • McMurray JJV, et al. Dapagliflozin in Patients with Heart Failure and Reduced Ejection Fraction (DAPA-HF). N Engl J Med. 2019;381(21):1995-2008. https://pubmed.ncbi.nlm.nih.gov/31535100/
  • Marso SP, et al. Semaglutide and Cardiovascular Outcomes in Patients with Type 2 Diabetes (SUSTAIN-6). N Engl J Med. 2016;375(19):1834-1844. https://pubmed.ncbi.nlm.nih.gov/27633186/
  • Cannon CP, et al. Ezetimibe Added to Statin Therapy after Acute Coronary Syndromes (IMPROVE-IT). N Engl J Med. 2015;372(25):2387-2397. https://pubmed.ncbi.nlm.nih.gov/26039521/
  • Virani SS, et al. 2023 ACC/AHA Guideline for the Diagnosis and Management of Chronic Coronary Disease. Circulation. 2023;148(9):e9-e119. https://www.ahajournals.org/doi/10.1161/CIR.0000000000001168
  • Wegovy (semaglutide) Full Prescribing Information. FDA. 2021, updated 2024. https://www.accessdata.fda.gov/drugsatfda_docs/label/2021/215256s000lbl.pdf