Weight-loss surgery reduces heart events, death vs. usual care in obesity, sleep apnea
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Key takeaways:
- In patients with obesity and obstructive sleep apnea, weight-loss surgery was linked to reduced risk for heart events and death.
- Patients who lost more than 10% of body weight had better outcomes.
In patients with obesity and obstructive sleep apnea, those who had weight-loss surgery had approximately 40% reduced risk for major adverse CV events and death compared with those who did not, according to the results of the MOSAIC study.
For the observational, long-term MOSAIC study, the researchers analyzed 13,657 patients who presented to the Cleveland Clinic Health System from 2004 to 2018 with BMI 35 kg/m2 to 70 kg/m2 and moderate to severe obstructive sleep apnea (OSA). The primary outcome was MACE, defined as MI, unstable angina, coronary intervention/surgery, ischemic stroke, hemorrhagic stroke, carotid intervention/surgery, HF, atrial fibrillation and all-cause mortality. The median follow-up was 5.3 years, and the researchers calculated cumulative incidence estimates for 10 years after the index date.
CVD in patients with OSA
“Cardiovascular disease is the main cause of morbidity and mortality in patients with OSA,” Ali Aminian, MD, director of the Bariatric and Metabolic Institute at Cleveland Clinic, told Healio. “Before MOSAIC, no therapy had been shown to reduce the risk of MACE and death in patients with OSA.”
The researchers compared 970 patients who underwent weight-loss surgery (Roux-en-Y gastric bypass or sleeve gastrectomy) with 12,687 patients matched based on baseline characteristics who did not undergo weight-loss surgery. Among the cohort, the mean age was 52 years, 55% were men and the median BMI was 41 kg/m2.
At 10 years, the mean between-group difference in body weight was 26.6 kg (95% CI, 25.6-27.6), translating to 19.3% less in the surgery group (95% CI, 18.6-19.9), the researchers found.
The 10-year cumulative incidence of MACE was 27% in the surgery group and 35.6% in the control group (adjusted HR = 0.58; 95% CI, 0.48-0.71; P < .001), according to the researchers.
In addition, the 10-year cumulative incidence of all-cause mortality was 9.1% in the surgery group and 12.5% in the control group (aHR = 0.63; 95% CI, 0.45-0.89; P = .009).
‘Quite large effect sizes’
“Improved outcomes after weight-loss surgery were expected because obesity is the main driver of OSA,” Aminian told Healio. “But the magnitude of the effects was surprising; 42% lower risk of major adverse cardiovascular events and 37% lower risk of death after metabolic surgery are quite large effect sizes.”
The difference in the primary endpoint was driven by patients who lost less than 10% of body weight (aHR = 0.45; 95% CI, 0.36-0.57; P < .001), and the difference was not significant in patients who lost more than 10% of body weight (aHR = 0.85; 95% CI, 0.67-1.08; P = .18).
“The current management guidelines of OSA recommend weight loss and lifestyle modifications,” Aminian told Healio. “Our findings support these recommendations. However, rather than focusing on lifestyle modification alone, treating obesity with more effective and durable methods such as bariatric surgery is required to improve cardiovascular outcomes and survival in patients with OSA and obesity. In the MOSAIC study, patients maintained near 25% weight loss 10 years after metabolic surgery. In a holistic approach to patients with OSA and obesity who are at risk for other cardiometabolic and health consequences of obesity, metabolic surgery is a reasonable choice in select patients.”
Newer weight-loss drugs may show similar treatment effects in this population, Aminian told Healio, noting that in the SURMOUNT-OSA trial, tirzepatide 10 mg or 15 mg (Zepbound, Eli Lilly), a GLP-1/GIP receptor agonist, improved the severity of OSA in adults with OSA and obesity. As Healio previously reported, top-line results of SURMOUNT-OSA were released in April and the full results are being presented today at the American Diabetes Association Scientific Sessions.
“The findings of [MOSAIC and SURMOUNT-OSA] are complementary and would indicate the importance of weight management in patients with obstructive sleep apnea, a disease which is estimated to affect nearly 1 billion people worldwide,” he said.
References:
- Cleveland Clinic study shows weight loss surgery cuts risk of heart complications and death in patients with obstructive sleep apnea and obesity. https://newsroom.clevelandclinic.org/2024/06/21/cleveland-clinic-study-shows-weight-loss-surgery-cuts-risk-of-heart-complications-and-death-in-patients-with-obstructive-sleep-apnea-and-obesity. Published June 21, 2024. Accessed June 21, 2024.
- Tirzepatide reduced sleep apnea severity by up to nearly two-thirds in adults with obstructive sleep apnea (OSA) and obesity. https://investor.lilly.com/news-releases/news-release-details/tirzepatide-reduced-sleep-apnea-severity-nearly-two-thirds. Published April 17, 2024. Accessed June 20, 2024.
For more information:
Ali Aminian, MD, can be reached at aminiaa@ccf.org; X (Twitter): @ali_aminian_md.
Perspective
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While other studies have noted very significant cardiovascular risk reduction after bariatric surgery, for example in patients with diabetes, the current study focuses on those with sleep apnea. I did not expect to see benefit from weight-loss surgery to this degree. This is a very substantial reduction in MACE and in mortality risk.
As a result of these findings, one might feel more comfortable sending people with morbid obesity and comorbid OSA to weight-loss surgery, based on two things. No. 1, after 10 years, many of these patients were able to keep their weight loss. There did not appear to be a lot of recidivism, which is a problem with weight-loss interventions. No. 2, there was a remarkable CV and mortality benefit. It would give one more reassurance that weight-loss surgery would be a reasonable option in someone who has severe obesity but also comorbid sleep apnea.
There have been some press reports of improvements in OSA with treatment with new weight-loss drugs, but to my knowledge there have not been any studies reported of improvements in CV events due to those drugs in the OSA population.
This was an excellent, well-done study, from an outstanding group of investigators, but one needs to keep in mind that it was retrospective. As the authors very transparently point out, there are limitations to retrospective studies. In addition, we cannot say that it was improvement in sleep apnea that gave rise to the benefit. Weight-loss surgery also brings improvements in blood pressure and metabolic profiles. So, it is hard to know where this remarkable benefit emerged from. This is also something we have to keep in mind.
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