Bariatric Surgery Improves Cardiovascular Outcomes in Patients with Obstructive Sleep Apnea

Patients with obstructive sleep apnea (OSA) and obesity who underwent bariatric surgery showed significant reduction in risk of death, reports a Cleveland Clinic study, the first to investigate the long-term effects of surgical weight loss on cardiovascular events in OSA. The study was published in the Journal of the American College of Cardiology.

OSA is a common condition, affecting 1 billion people worldwide, most of whom (75%) have obesity. Obesity creates excess fat accumulation around the neck which can compress airways during sleep, causing chronic overnight physiologic stresses. OSA is associated with many types of cardiovascular disease, including hypertension, heart failure, coronary artery disease and atrial fibrillation.

Since obesity is a major pathophysiological driver of OSA, patients receive guidance on weight loss and lifestyle management. “In reality, this approach doesn’t work for many patients. Most patients are unable to lose enough weight and keep it off to meaningfully influence clinical outcomes,” says Ali Aminian, MD, the study’s primary investigator and Director of the Bariatric and Metabolic Institute at Cleveland Clinic.

“There are currently no approved drug therapies for obstructive sleep apnea,” says Steven Nissen, MD., Chief Academic Officer of the Heart, Vascular & Thoracic Institute at Cleveland Clinic and co-senior author of the study. “Before this study, no therapy had been shown to reduce the risk of major adverse cardiovascular events and death in patients with sleep apnea.”

Bariatric surgery is the most effective and durable treatment for obesity; previous Cleveland Clinic studies have shown its benefits in patients with other medical conditions, such as diabetes, kidney disease, and fatty liver disease. “If you help patients lose weight, their obesity-related medical conditions will improve,” says Dr. Aminian.

However, no previous studies had examined the association between bariatric surgery and the incidence of major adverse cardiovascular events (MACE) or death in patients with OSA and obesity.

Study specifics

To address this knowledge gap, in the MOSAIC (Metabolic surgery for OSA and Incident Cardiovascular disease) study, investigators analyzed a cohort of 13,657 adult Cleveland Clinic patients (54.9% men; mean age, 52.0 years)with a BMI of 35-70 kg/m² and the presence of moderate-to-severe OSA (apnea hypopnea index ≥ 15 events/h diagnosed by a sleep study test) between 2004 and 2018. There were 970 patients in the bariatric surgery group and 12,687 patients in the nonsurgical control group who were followed for a median of 5.3 years until September 2022.

Findings show clear differences

At 10 years, patients in the bariatric surgery group had lost 33.2 kg and patients in the nonsurgical control group had lost 6.64 kg. Patients maintained nearly 25% of their weight loss 10 years after bariatric surgery.

The cumulative incidence of MACE at 10 years was 27.0% in the bariatric surgery group and 35.6% in the nonsurgical group (adjusted hazard ratio = 0.58 [95% CI, 0.48-0.71]). Regarding all-cause mortality at 10 years, the cumulative evidence was 9.1% in the bariatric surgery group and 12.5% in the nonsurgical group (adjusted hazard ratio = 0.63 [95% CI, 0.45-0.89]).

Bariatric surgery was also associated with a 70% lower risk of developing heart failure.

“These findings show a very significant risk reduction in this patient population: a 42% lower risk of cardiovascular events and a 37% lower risk of death. Currently, there is no other treatment that can provide these benefits, especially the reduced risk of death,” says Dr. Aminian.

Looking ahead

The investigators hope that these findings will lead providers at Cleveland Clinic and other institutions to refer more patients with OSA for a bariatric surgery consultation. They note that bariatric surgery is a powerful treatment for obesity that can have a meaningful impact on patients’ lives.

“The current management guidelines for obstructive sleep apnea recommend weight loss and lifestyle modifications,” says Nancy Foldvary-Schaefer, DO, Director of Cleveland Clinic’s Sleep Disorders Center. “The MOSAIC study findings support those recommendations. However, rather than focusing on lifestyle modification alone, treating obesity with more effective and durable methods such as bariatric surgery would be required to improve cardiovascular outcomes and survival in patients with obstructive sleep apnea and obesity.”

“Treating sleep apnea with CPAP improves the symptoms. But by addressing obesity, which is the root cause of sleep apnea in many patients, we can improve OSA and provide several other health benefits to our patients,” adds Dr. Aminian.