Weight reduction surgery lowers BMI, positive airway pressure in OSA

Key takeaways:

• Benefits of weight reduction surgery were greater among adults with higher BMIs prior to the procedure.
• Positive airway pressure dropped by 1.3 cm/H₂O after the surgery in the three highest baseline BMI groups.

Following a weight reduction surgery/procedure, adults with obesity and obstructive sleep apnea lost weight and had decreased positive airway pressure, according to research presented at SLEEP 2024.

“For everyday clinicians, the biggest challenge to PAP therapy to treat OSA is long-term adherence,” Fatima Sert-Kuniyoshi, PhD, director of clinical research at ResMed, told Healio. “The main potential benefit of lower PAP pressures after a weight loss regimen is improved patient comfort, which may increase adherence. So weight management should always be part of the discussions with patients and integrated into the multidisciplinary management of OSA.

“With that said, I’d like to emphasize that while these findings suggest significant improvements in OSA severity, the reductions in PAP pressure may not fully reflect the complete resolution of OSA,” she continued. “Therefore, clinicians should continue to monitor patients after the weight loss regimen, retest patients and optimize PAP therapy management to improve overall patient outcomes.”

Using 2015 to 2021 administrative claims data, Sert-Kuniyoshi and colleagues assessed 17,284 adults (mean age, 45.6 years; 74.7% women) with OSA who had a BMI of 30 kg/m² or more before undergoing a weight reduction surgery/procedure to find out how this surgery/procedure impacts positive airway pressure (PAP) therapy pressure after at least 1 year.

“We used PAP therapy pressure as a proxy to infer OSA severity,” Sert-Kuniyoshi told Healio.

Higher BMIs before the surgery/procedure corresponded to higher baseline apnea-hypopnea index (AHI) scores.

The lowest BMI group (≥ 30 kg/m² to < 35 kg/m²) had an AHI of 16.9 events/hour, which gradually increased with larger BMIs to 18.2 events/hour (≥ 35 kg/m² to < 40 kg/m²), 19.9 events/hour (≥ 40 kg/m² to < 45 kg/m²), 23.4 events/hour (≥ 45 kg/m² to < 50 kg/m²), 25.1 events/hour (≥ 50 kg/m² to < 60 kg/m²) and lastly 27 events/hour (≥ 60 kg/m²).

In terms of weight loss at least 1 year after the surgery/procedure, researchers observed larger average declines in BMI with increasing baseline BMI:

• –3.3 kg/m² (≥ 30 kg/m² to < 35 kg/m²);
• –5.7 kg/m² (≥ 35 kg/m² to < 40 kg/m²);
• –6.8 kg/m² (≥ 40 kg/m² to < 45 kg/m²);
• –8.1 kg/m² (≥ 45 kg/m² to < 50 kg/m²);
• –10.3 kg/m² (≥ 50 kg/m² to < 60 kg/m²); and
• –13 kg/m² (≥ 60 kg/m²).

Those with higher BMIs at baseline continued to benefit more from the procedure when researchers evaluated PAP changes.

Compared with the median PAP taken 1 month before the surgery/procedure, median PAP therapy pressure measured at least 1 year after dropped by 0.8 cm/H₂O in the lowest baseline BMI group, 0.9 cm/H₂O in the 35 kg/m² to less than 40 kg/m² group and by 1 cm/H₂O in the 40 kg/m² to less than 45 kg/m² group.

In the three highest baseline BMI groups, median PAP was reduced by 1.3 cm/H₂O after the surgery/procedure.

"It is important to highlight that resolution of symptoms and OSA remission may not occur, underscoring the complexity of OSA management,” Sert-Kuniyoshi told Healio.

“Future studies should prioritize including patient-reported outcomes to gauge the impact of weight loss strategies on OSA management,” Sert-Kuniyoshi added. “Understanding how patients perceive improvements in symptoms and treatment comfort is crucial for ensuring continued adherence to PAP therapy, especially after significant weight loss.”

Editor's note: This article was updated to include comments from Fatima Sert-Kuniyoshi, PhD, on June 28, 2024.