Obstructive sleep apnea (OSA) and obesity are related. Weight loss can improve OSA, sometimes enough to eliminate it altogether. However, if OSA is severe, weight loss alone is often not enough to cure OSA.
Most patients who undergo weight loss surgery have OSA, and most use CPAP prior to weight loss surgery. Unfortunately, most patients discontinue their CPAP use after weight loss surgery. This study assessed long-term CPAP use in 21 patients who had undergone gastric banding. Results showed that body-mass index significantly increased by 6.8 in those patients who did not use their CPAP after weight loss surgery. And BMI dropped by 1.8 in those patients that were adherent to CPAP therapy after weight loss surgery.
Another important point is that OSA persisted in almost all of the patients who underwent the surgery, despite the substantial weight loss (average 121 pounds lost). And, after 7.2 years of follow up, the majority of patients had gained back some weight (22 pounds).
So the data in this study suggest that CPAP adherence for the long term may help with weight loss maintenance. Remember this is a small study though. Other confounding factors could contribute to reasons why some patients chose to keep using CPAP. For instance, some may have continued only because using CPAP made them sleep better or have more energy. And that increased energy could have helped them keep exercising, which may help maintain weight. Or those that kept using CPAP may have adhered better to diet restrictions.
In the end, follow up with the sleep medicine specialist is important after weight loss surgery. In that way, post-operative OSA severity can be assessed after the first year. Then, the patient and sleep medicine physician can discuss the pros and cons of continuing CPAP therapy if necessary.