TABLE IX.D.11.

Evidence for bariatric surgery and OSA

Study	Year	LOE	Study design	Study groups	Clinical end-point	Conclusion
Ashrafian et al.195	2015	1c	Systematic review	1. Bariatric surgery 2. Non-surgical weight loss	AHI before and after intervention	1. Surgical intervention associated with significant reduction in post op AHI (but significant heterogeneity). 2. Non-surgical intervention also associated with significant post op reduction in AHI (but significant heterogeneity).
Bakker et al.1987	2018	2b	1 RCT, low quality, did not meet power	1. Laparascopic gastric banding 2. CPAP	AHI at 9 and 18 months after intervention	No difference in AHI off CPAP between groups at 9 or 18 months.
Buchwald et al.1993	2004	1c	Systematic review	Meta-analysis of improvement/resolution of OSA in patients undergoing bariatric surgery	Improvement/resolution of OSA	83.6%–85.7% resolution/improvement in OSA among total patient population, but significant heterogeneity of studies, with inclusion of RCTs, non-randomized CTs, and uncontrolled case series. Also included all types of bariatric procedures.
Dixon et al.194	2012	1b	1 RCT	1. Diet, exercise, behavioral program 2. Laprascopic adjustable gastric banding	Reduction in AHI at 2 years	Surgical group achieved significantly greater weight loss but no difference in AHI reduction. Patterns suggest that much of benefit to AHI is associated with mild to moderate weight loss with diminishing returns with further weight loss.
Feigel-Guiller et al.1988	2015	1b	1 RCT	1. Intensive nutritional care 2. Laprascopic adjustable gastric banding	Rate of PAP weaning (AHI < 20) at years 1 and 3	Surgical group achieved significantly greater weight loss at years 1 and 3, but no difference in ability to wean from PAP at years 1 and 3.
Greenburg et al.1994	2009	1c	Systematic review	Meta-analysis of improvement/resolution of OSA in patients undergoing bariatric surgery	1. BMI reduction 2. AHI reduction	Significant heterogeneity between studies. Significant reduction in BMI and AHI seen, but AHI was still moderate. Bariatric surgery improves, but does not resolve OSA.
Haines et al.1991	2007	2c	Prospective uncontrolled trial	Patients with OSA undergoing bariatric surgery	1. BMI reduction 2. RDI reduction at 6–42 months after surgery	Significant reduction in BMI and RDI, but RDI remained moderate. Bariatric surgery improves, but does not resolve OSA.
Hariri et al.1995	2018	2c	Retrospective review	1. Obesity classes (I, II, III) 2. Sleeve gastrectomy versus Roux-en-Y Bypass 3. Pre-op AHI severity (mild, med, severe); All 3 evaluated at 6 months and 1 year	Subjective postop OSA remission (STOP-BANG <2 and discontinuation of CPAP)	No difference in subjective OSA remission between obesity class groups at 6 or 12 months. No difference in subjective OSA remission by type of surgery at 6 or 12 months. No difference in subjective OSA remission by pre-op AHI severity.
Lettieri et al.1983	2008	2c	Prospective uncontrolled trial	Patients with OSA undergoing bariatric surgery	AHI severity (mild, mod, severe) at 1 year post bariatric surgery	Significant change in BMI, ESS score, and AHI postop at 1 year, but AHI remained moderate. Severity improved in 50%.
Miras et al.1996	2018	2c	Retrospective review	All patients in the National Bariatric Surgery Registry (NBRS) from 2000 to 2015 totaling 50,782 patients	Prevalence of OSA before and after bariatric surgery recorded years 1–5 postoperatively	19.7% of patients had diagnosed sleep apnea prior to bariatric surgery (79.8% with no diagnosis or indication of OSA). Postoperatively, the prevalence dropped to 10%. However, there are no specific numbers listed for sleep apnea results post-procedure. In general, a decrease in the prevalence of OSA reported after bariatric surgery.
Quintas-Neves et al.1989	2016	2a	Systematic review	Review of 22 cohort studies involving pre- and postoperative OSA in the setting of bariatric surgery	Improvement/resolution of OSA. Type of bariatric surgery and impacts on OSA	Significant reduction in BMI and AHI values following bariatric surgery with short-term follow-up (1–2 years). Greater reduction in AHI values in those undergoing restrictive and malabsorptive procedures (roux-en-y) vs. restrictive alone (gastric banding)
Sarkhosh et al.1990	2013	2a	Systematic review	Sixty-nine studies reviewed: three RCTs, 11 controlled trials, 55 case series	Type of bariatric surgery and impacts on OSA	Significant improvement or resolution in OSA following bariatric surgery. Interventions with a malabsoprtive mechanism, which alter the gut anatomy and transit time, are more efficacious in impacting in obstructive sleep apnea.
Wong et al.1963	2018	2a	Systematic review	Meta-analysis of improvement/resolution of OSA in patients undergoing bariatric surgery. 15 studies included in analysis	Improvement and resolution of OSA following bariatric surgery. Secondary measures such as BMI, ESS, and comparisons to intensive lifestyle interventions were performed	Significant reduction in AHI following bariatric surgery with greater reduction noted in those with higher presurgical AHI. Two times greater reduction in AHI in bariatric surgery group compared to intensive lifestyle interventions. 97.5% of bariatric patients still had residual OSA (AHI > 5). Also noted no correlation between amount of weight lost and change in AHI.
Zhang et al.1992	2019	2a	Systematic review	Systematic review of improvement/resolution of OSA in patients undergoing bariatric surgery. 15 studies included: 13 prospective, one RCT, and one retrospective	Improvement and resolution of OSA following bariatric surgery. Primary endpoints included AHI, mean SaO2, and nadir SaO2	Improvement of mean and nadir SaO2 following bariatric surgery. Significant reduction in AHI between pre- and post-surgical period. Significant heterogeneity noted.