REVIEW

The Impact of Bariatric Surgery on Obstructive Sleep Apnea:A Systematic Review

Kourosh Sarkhosh & Noah J. Switzer & Mustafa El-Hadi &Daniel W. Birch & Xinzhe Shi & Shahzeer Karmali

Published online: 9 January 2013# Springer Science+Business Media New York 2013

Abstract There is a strong relationship between obesityand the development of obstructive sleep apnea (OSA).Respectively, bariatric surgery is often touted as themost effective option for treating obesity and its comor-bidities, including OSA. Nevertheless, there remainspaucity of data in the literature of the comparison ofall the specific types of bariatric surgery themselves. Inan effort to answer this question, a systematic reviewwas performed, to determine, of the available bariatricprocedures [Roux-en-Y gastric bypass, laparoscopicsleeve gastrectomy, or biliopancreatic diversion (BPD)],which procedures were the most efficacious in the treat-ment of OSA. A total of 69 studies with 13,900 patientswere included. All the procedures achieved profoundeffects on OSA, as over 75 % of patients saw at leastan improvement in their sleep apnea. BPD was the mostsuccessful procedure in improving or resolving OSA,with laparoscopic adjustable gastric banding being theleast. In conclusion, bariatric surgery is a definitivetreatment for obstructive sleep apnea, regardless of thespecific type.

Keywords Bariatric surgery . Obesity . Obstructive sleepapnea

Introduction

Obesity is a common disease worldwide affecting adultsand children. It is defined as a body mass index (BMI)of >30 kg/m2. Obesity is an important risk factor fordevelopment of several comorbidities including obstruc-tive sleep apnea (OSA) [1]. OSA is more prevalent in amore obese patient population. The odds ratio of devel-oping OSA increases by almost 1.14 with each unitincrease in the BMI [2]. OSA usually presents withrecurrent episodes of partial or complete upper airwayobstruction during sleep. Diagnosis of OSA is made inpatients with at least five apneic or hypopneic eventsper hour. In terms of severity, OSA can be categorizedbased on the severity of apnea–hypopnea index (AHI).Patients with AHI of 5–14, 15–29, or >30 events perhour are considered to have mild, moderate, or severeOSA, respectively [2].

Bariatric surgery is currently the only available option fora long-term and sustainable weight loss [3]. These bariatricsurgical procedures also cause improvement or resolution ofobesity-related comorbidities. In a recent meta-analysis,Greenburg et al. reported a significant reduction in AHI inpatients following bariatric surgery. These investigatorsfound on average a reduction of 17.9 kg/m2 and 38.2 even-ts/hour in patients’ BMI and AHI following bariatric sur-gery, respectively [4].

Several bariatric surgical procedures are currently avail-able for the treatment of morbid obesity. These can becategorized into either purely restrictive procedures suchas laparoscopic adjustable gastric banding (LAGB), lapa-roscopic sleeve gastrectomy (LSG), or vertical bandedgastroplasty (VBG), restrictive with a mild malabsorptivecomponent such as Roux-en-Y gastric bypass (RYGB), orlargely malabsorptive with a mild restrictive componentsuch as biliopancreatic diversion with or without duodenalswitch (BPD).

K. Sarkhosh :D. W. Birch :X. Shi : S. Karmali (*)Center for the Advancement of Minimally Invasive Surgery(CAMIS), Royal Alexandra Hospital, 10240 Kingsway,Edmonton, AB T5H 3V9, Canadae-mail: shahzeer@ualberta.ca

N. J. SwitzerFaculty of Medicine and Dentistry, University of Alberta,Edmonton, AB, Canada

M. El-Hadi :D. W. Birch : S. KarmaliDepartment of Surgery, University of Alberta, Edmonton, AB,Canada

OBES SURG (2013) 23:414–423DOI 10.1007/s11695-012-0862-2

Although there is evidence in the literature suggestive ofimprovement or resolution of comorbidities such as diabetes,hypertension, or sleep apnea in patients following certainbariatric surgical procedures [3–5], there still remains a pau-city of research on evaluating and comparing the effects of alltypes of bariatric procedures on OSA. The purpose of thisreview is to systematically review the literature regarding theefficacy of bariatric surgical procedures in obese adult patientson improving OSA.

Methods

A comprehensive search of all electronic databases (MED-LINE, PubMed, Embase, Scopus, Dare, Clinical Evi-dence, BIOSIS, Previews, TRIP, Web of Science,Health Technology Database, Conference abstracts, clin-ical trials, and the Cochrane Library database) wasperformed, using the search terms: bariatric surgery orobesity surgery or weight loss surgery or metabolicsurgery or gastric bypass or gastric band or sleevegastrectomy and sleep apnea. All human studies from1946 to December 2011 were included. The referencelists of all included studies were manually examined toidentify additional potentially relevant publications.“Grey literature,” including conference abstracts, regis-tered clinical trials, and web sites, was searched includ-ing the conference papers Index and OCLC Papers First.Randomized controlled trials, non-randomized controlledtrials, case-controlled studies, and case series were consideredfor this study.

Data collection and analysis

Studies of any design including adult obese patients un-dergoing bariatric surgery from 1946 to 2011 were con-sidered. An initial electronic search was conducted by oneof the authors experienced in database searches (X.S.). Apre-screening was subsequently performed to identify theclearly irrelevant papers based on the title, abstract, andkeywords. Three reviewers (K.S., X.S., and M.E.) thenindependently evaluated the full-text version of these stud-ies for their relevance. Studies investigating the effect ofbariatric surgery on OSA in adults (age >18 years old)were included. Non-human or non-English studies wereexcluded.

Three independent reviewers (K.S., M.E., and X.S.)extracted data from the included papers. This includeddata on patients’ demographics (age, gender), type ofthe study, type of performed surgery, as well as baselineand post-intervention outcomes [incidence of sleep ap-nea, mean BMI, and excess weight loss (EWL)]. Theprimary outcome was to evaluate the effect of different

types of bariatric procedures on sleep apnea. Secondaryoutcomes measured included the average EWL associ-ated with each of these procedures. Due to lack ofRCTs, different comparison groups among controlledtrials and the high heterogeneity (different age group,initial BMI, surgical techniques, etc.) across studies, ameta-analysis was not conducted in this paper. Pooleddata were reported as mean/SD (range) for continuousvariables, frequency and percentage were used for categoricalvariables.

Results

Search Results

A total of 2,110 studies were identified for screeningusing our search criteria (Fig. 1). After careful assessmentof these studies and based on our outlined exclusioncriteria, 297 studies were identified for the abstract review.Of these, a total of 69 met our inclusion criteria and wereincluded in the study. These included 3 randomized con-trolled trials [6–8], 11 controlled trials [9–19], and 55 caseseries [20–74].

Included studies

A total of 69 studies with 13,900 patients were includedfor this review. From these, 36, 21, 8, and 4 studieswere on RYGB, LAGB, LSG, and BPD, respectively.The remainder of the studies investigated the effect ofbariatric surgery on improvement of sleep apnea withdifferent types of bariatric procedures combined togetheras one group (Appendix 1).

In the RYGB group, there were a total of 5,430patients with the mean age of 45.4±8.5 years (range 33–68). The average follow-up time was 29 months (range 9–120). Sixty-nine percent of these patients were females.The mean preoperative BMI in this group was 51.6±8.3(range 42–79.9). Sleep apnea was present on average in34.9 % of patients before undergoing surgery. RYGBresulted in resolution and improvement of sleep apnea in73 and 30 % of patients, respectively. On average, 79 %of patients experienced either resolution or improvementof their sleep apnea. The mean EWL was 75.2±26.8 %(range 26.5–159) (Appendix 2).

In the LAGB group, there were a total of 4,095 patientswith the mean age of 41.8±6.9 years (range 30.4–63.6). Theaverage follow-up time was 34.4 months (range 12–156).Seventy-four percent of these patients were females. Themean preoperative BMI was 46.1±5.2 (range 32.7–55.9).Sleep apnea was present on average in 28.7 % of patientsbefore undergoing surgery. LAGB resulted in resolution and

OBES SURG (2013) 23:414–423 415

improvement of sleep apnea in 70.5 and 32 % of patients,respectively. On average, 77 % of patients experiencedresolution or improvement of their sleep apnea. The meanEWL in this group was 66.8±33.0 % (range 28–112)(Appendix 2).

In the LSG group, there were a total of 543 patientswith the mean age of 39.4±4.2 years (range 33–45). Theaverage follow-up time was 24.7 months (range 12–38).Sixty-four percent of these patients were females. Themean preoperative BMI was 47.7±4.9 (range 41.8–57.3).Sleep apnea was present on average in 24 % of patientsbefore undergoing surgery. LSG resulted in resolutionand improvement of sleep apnea in 72 and 51 % ofpatients, respectively. On average, 86 % of patients ex-perienced resolution or improvement of their sleep apnea.The mean EWL in this group was 46.1±10.5 % (range31–55.5) (Appendix 2).

In the BPD group, there were a total of 246 patientswith the mean age of 40.7±4.3 years (range 34.8–45).The average follow-up time was 19 months (range 4–24). Seventy-five percent of these patients were females.The mean preoperative BMI was 50.5±4.9 (range 45.3–56.9). Sleep apnea was present on average in 18.3 % ofpatients before undergoing surgery. BPD resulted in reso-lution of sleep apnea in 82.3 % of patients. On average,99 % of patients experienced resolution or improvementof their sleep apnea. The mean EWL in this group was53.7±35.9 % (range 13.7–83.1) (Appendix 2).

In the combined surgical procedures (MIX) group, therewere a total of 3,586 patients with the mean age of 42.4±4.4 years (range 34.7–47). The average follow-up time was21.8 months (range 4.5–54). Fifty-six percent of these

patients were females. The mean preoperative BMI was48.3±5.6 (range 42.2–56). Sleep apnea was present onaverage in 11 % of patients before undergoing surgery.MIX resulted in resolution and improvement of sleep apneain 63 and 31 % of patients, respectively. On average, 88.5 %of patients experienced resolution or improvement of theirsleep apnea. The mean EWL in this group was 68.3±14.2 %(range 53–91) (Appendix 2).

Discussion

Obesity is a common disease worldwide and a known riskfactor for development of sleep apnea. Bariatric surgery iscurrently the only available method for a sustainable andlong-term weight loss. The purpose of this study was tosystematically evaluate the effect of different types of bari-atric surgery on sleep apnea.

Our systematic review based on the current availableevidence shows that bariatric surgery improves orresolves sleep apnea in a majority of bariatric patientsregardless of the specific operation. This is an importantclinical endpoint, as it is well known that OSA is notjust a disorder of excessive daytime somnolence butrather its existence carries important metabolic morbid-ity. OSA is an independent risk factor for metabolicsyndrome, leading to increased blood pressure, poorlipid, and glucose control [75]. In a well-known sys-tematic review and meta-analysis, Buchwald et al. foundsimilar results to our study using a widened umbrelladefinition of obstructive sleep apnea (including sleep-disordered breathing and Pickwickian syndrome), with

2110 Citations Identified for Screening

1813 Rejected (Met Exclusion criteria)

297 Abstracts Reviewed

69 Primary Studies Included

3 Randomize Controlled Trial11 Controlled Trial55 Case Series

228 Rejected (Did Not Meet Inclusion Criteria)

Wrong Publication Type (case report, experts opinions)Animal modelsPediatric studiesTechnique onlyNo outcome measured

•••••

•••

Fig. 1 Flowchart showingsearch results for the systematicreview

416 OBES SURG (2013) 23:414–423

83.6 % of patients experienced resolution or improve-ment in their OSA [3]. In recent studies, it has beenbeginning to be shown that these results can be main-tained in longer term follow-up [46, 76]. The authorsconcluded that the reduction in intra-abdominal pressuredue to excess weight loss following surgery leads toclinically significant improvement in blood oxygenation,resulting in favorable effects on the cerebral respirationpathways.

Interestingly, the efficacy of the specific types of bariatricintervention on improving sleep apnea was different thanour study. In the Buchwald et al. study, gastric bypass(94.8 %) was the most successful in improving or resolvingOSA then gastroplasty (90.7 %) and gastric banding(68.0 %) being the least effective [3]. In our study, BPD(99.0 %) was the most successful, then LSG (85.7 %),followed by RYGB (79.2 %) and LAGB (77.5 %) the least(Fig. 2). This difference could possibly attributed to therelatively low number of patients analyzed within eachsubgroup in the Buchwald review [3]. However, the trendbetween both systematic reviews is that interventions with amalabsorptive mechanism like RYGB and BPD which alterthe gut anatomy and transit time are more efficacious inresolving or improving sleep apnea than purely restrictiveones like LAGB, which simply reduce oral intake. Inter-estingly, LSG, a primarily restrictive procedure with ahormonal element, produced resolution rates greater thanRYGB and LAGB. The difference in efficacies can bepartially explained, as Ashrafian et al. proposed that the

improvement in OSA following bariatric surgery was notonly due to weight-dependent effects, like decreased me-chanical force on the neck, upper airway, and diaphragm,as suggested by Buchwald et al., but also due to weight-independent, metabolic effects [3, 77]. These metaboliceffects are summarized with the acronym BRAVE: bileflow alteration, reduction of gastric size, anatomical rear-rangement, vagal manipulation, and enteric gut hormonemodulation [77]. In addition, sleep apnea and obesity arenow recognized as being correlated to low-grade systeminflammation, while postsurgical changes following mal-absorptive bariatric procedures have resulted in a protec-tive anti-inflammatory state, with various inflammatorybiomarkers being decreased [78]. The most recognizedare TNF-alpha and IL-6; however recently, TNF-alphareceptor 2 has been shown to be a specific marker forsleep apnea, as it is an independent predictor of sleepapnea improvement [78]. It is evident that more studiesneed to be devoted to identifying the key physiologicalchanges that occur after surgical intervention to fully becomfortable in explaining why procedures like BPD leadto better results than LAGB.

It seems that OSA could even be underreported amongpatients undergoing bariatric surgery. Ravesloot et al.found that at the time of surgery only 13 % of patientswere diagnosed with OSA, even though almost 70 % ofthose patients fulfilled the criteria, with over 40 % ofthose patients meeting the criteria for severe OSA [79].This could be correlated to the discovery that subjectivesleepiness and daytime functioning impairment corre-spond poorly with the severity of OSA, meaning familypractitioners need to be highly vigilant in screening allobese patients with appropriate sleep studies rather thanrelying on subjective self-reporting [80]. This early rec-ognition of at-risk patients is especially important preopera-tively to avoid perioperative and postoperative complications[81, 82].

Conclusion

Our systematic review shows that bariatric surgery has asignificant effect on sleep apnea, inducing resolution orimprovement in the majority of cases. It appears that moremalabsorptive procedures, especially biliopancreatic diver-sion, are the most efficacious. OSA is still being underdiagnosed it seems, and measures must be taken to screenat-risk individuals. For obese individuals with OSA, bariat-ric surgery remains a viable option in patients with sleepapnea.

Conflict of Interest The authors do not have any commercial asso-ciations that might be a conflict of interest in relation to this article.

77.5 79.2

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LAGB RYGB LSG BPD MIX

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Specific Bariatric Surgery

Fig. 2 Percentage improvement or resolution in OSA of the specificbariatric surgeries. OSA obstructive sleep apnea, LSG laparoscopicsleeve gastrectomy, LAGB laparoscopic adjustable gastric banding,RYGB Roux-en-Y gastric bypass, MIX Studies with mixed procedures

OBES SURG (2013) 23:414–423 417

Table 1 Baseline characteristics of the included studies in the systematic review

Investigator Study design Year Surgery Patients (n) Mean age (years) Gender (% female) Mean BMI (kg/m2) Follow-up (months)

Chopra [20] Case series 2007 LSG 174 39.6 85.6 48.97 36

DePaula [21] Case series 2011 LSG 120 41.4 59.2 45 38.4

Kasalicky [22] Case series 2008 LSG 61 37.3 68.9 41.8 18

Kehagias [6] RCT 2011 LSG 30 36 73.3 45.8 36

Lakdawala [9] Controlled T 2010 LSG 38 38 52 46 12

Omana [10] Controlled T 2010 LSG 49 45 36 52 15

Silecchia [23] Case series 2006 LSG 41 44.6 68.3 57.3 22.1

Wong [24] Case series 2009 LSG 30 33 70 45 20

Abu-Abeid [25] Case series 2001 LAGB 18 63.6 72.2 44.4 21.9

Ahroni [26] Case series 2005 LAGB 195 43.8 82.8 45.8 12

Angrisani [7] RCT 2007 LAGB 27 33.8 81.5 43.4 60

Bowne [11] Controlled T 2006 LAGB 60 41.9 83.3 55.4 16.2

Dixon [27] Case series 2005 LAGB 25 44.7 32 52.7 17.7

Dolan [12] Controlled T 2004 LAGB 23 39 55.9 24

Frigg [28] Case series 2004 LAGB 295 41 79 45 44

Galvani [13] Controlled T 2006 LAGB 470 41 80 47 12

Himpens [29] Case series 2011 LAGB 82 50 90.2 41.5 156

Kasza [30] Case series 2011 LAGB 144 43 90.3 45.6 24

Korenkov [31] Case series 2007 LAGB 145 37.5 72.4 48.5 60

Lee [32] Case series 2006 LAGB 91 31.2 48.4 42.7 36

Lettieri [33] Case series 2008 LAGB 24 47.9 75 51 14

O’Brien [34] Case series 2002 LAGB 709 41 85.04 45 12

Omana [10] Controlled T 2010 LAGB 74 41 58 44 17

Parikh [35] Case series 2006 LAGB 93 44.6 81.7 32.7 36

Rubenstein [36] Case series 2002 LAGB 63 40.8 88.9 48.8 36

Spivak [37] Case series 2005 LAGB 500 42 86.4 45.2 36

Weiner [38] Case series 2002 LAGB 984 38.4 85.9 46.8 55.5

Yu [39] Case series 2011 LAGB 16 30.4 62.5 47.2 12

Wong [24] Case series 2009 LAGB 57 41 58 40 20

Bowne [11] Controlled T 2006 RYGB 46 42.8 76.1 56.7 16.2

Brolin [14] Controlled T 1992 RYGB 22 38.7 81.8 63.4 24

Brolin [14] Controlled T 1992 RYGB 23 36.5 65.2 61.6 24

Cordera [40] Case series 2004 RYGB 54 46 77.8 46 73.2

Fritscher [41] Case series 2007 RYGB 12 44.6 25 51.55 24.2

Gagne [42] Case series 2011 RYGB 105 49 92.4 42 31

Galvani [13] Controlled T 2006 RYGB 120 41 90 46 12

Gonzalez [43] Case series 2003 RYGB 52 55 87 49 12

Hamed [15] Controlled T 2008 RYGB 177 42.4 81.9 44.1 12

Hamed [15] Controlled T 2008 RYGB 118 42.5 83.9 56.7 12

Haines [44] Case series 2006 RYGB 349 45 92 52 11

He [45] Case series 2004 RYGB 310 41.9 77.1 46.3 42

Higa [46] Case series 2011 RYGB 242 81 120

Huerta [47] Case series 2007 RYGB 55 49.1 38 49.3 24

Kehagias [6] RCT 2011 RYGB 30 33.7 73 44.9 36

Lakdawala [9] Controlled T 2010 RYGB 50 42 54 45.2 12

Maher [48] Case series 2007 RYGB 450 42.2 80.4 49.5 12

Nelson [49] Case series 2006 RYGB 257 45 60.3 61 48

Appendix 1

418 OBES SURG (2013) 23:414–423

Table 1 (continued)

Investigator Study design Year Surgery Patients (n) Mean age (years) Gender (% female) Mean BMI (kg/m2) Follow-up (months)

Nelson [50] Case series 2006 RYGB 25 68 72 50 9

Pajecki [51] Case series 2007 RYGB 75 76 56.7 87

Papasavas [52] Case series 2002 RYGB 116 42.4 87 49.3 18

Papasavas [53] Case series 2004 RYGB 71 59 76.1 50.2 17

Peluso [54] Case series 2007 RYGB 400 44.8 84 48 12.8

Pinheiro [16] Controlled T 2008 RYGB 58 53 44 53.4 48

Pinheiro [16] Controlled T 2008 RYGB 48 56 31 54.7 48

Raftopoulos [19] Controlled T 2005 RYGB 43.2 82.4 51.5 18.25

Raftopoulos [19] Controlled T 2005 RYGB 40.8 59.5 79.9 17.7

Schauer [55] Case series 2000 RYGB 275 42 81 48.32 16.9

Skroubis [8] RCT 2006 RYGB 65 33 53 44.6 24

Slotman [56] Case series 2010 RYGB 61 37 66 77 36

Sosa [57] Case series 2004 RYGB 23 64.4 48.5 12

Suter [58] Case series 2011 RYGB 379 39.4 74.4 46.3 60

Tejirian [59] Case series 2008 RYGB 1096 43.8 84 50 2 4

Varela [60] Case series 2007 RYGB 56 46 64 49 12

Wittgrove [61] Case series 2000 RYGB 12

Wittgrove [62] Case series 2009 RYGB 120 63.4 62 45.2 12

Yan [63] Case series 2008 RYGB 59 49.3 14 47.9 50

Wong [24] Case series 2009 RYGB 7 39 71 49 20

De Luis [64] Case series 2005 BPD 19 42.1 79 48.6 4

Dolan [12] Controlled T 2004 BPD 23 41 69.6 56.9 24

Simard [65] Case series 2004 BPD 139 45 98 51.4 24

Skroubis [8] RCT 2006 BPD 65 34.8 52 45.3 24

Busetto [66] Case series 2005 MIX 17 0 55.8 6

Closset [67] Case series 2004 MIX 273 36.8 83.3 45.3

Dhabuwala [68] Case series 2000 MIX 157 41 77.1 45 30

Grunstein [17] Controlled T 2007 MIX 1,729 46.9 70.2 42.2 24

Guardiano [69] Case series 2003 MIX 8 44.6 88 49 34

Iannelli [70] Case series 2009 MIX 15 43.6 93 54 7.3

Karason [18] Controlled T 2000 MIX 1,210 47 67 42.2 24

Pillar [71] Case series 1994 MIX 14 46 21 45 4.5

Scheuller[72] Case series 2001 MIX 15 34.7 33

Sugerman [73] Case series 1986 MIX 38 41 24 12

Sugerman [74] Case series 1992 MIX 110 62 56 54

BMI body mass index, LSG laparoscopic sleeve gastrectomy, LAGB laparoscopic adjustable gastric banding, RYGB Roux-en-Y gastric bypass,MIXstudies with mixed procedures, n number of patients, %F percent females, Controlled T controlled trial, RCT randomized controlled trial

Appendix 2

Table 2 Outcomes following bariatric surgery – systematic review

Author Year Surgery Sleep apnea Weight loss

Inc. Pre-op AHI Post-op AHI Persist Improve Resolve R + I Post-op BMI %EWL

Chopra [20] 2007 LSG 0.178 0.093 0.677 0.23 0.907 35 55.5

DePaula [21] 2011 LSG 0.1 0 1 1 25.7

Kasalicky [22] 2008 LSG 0.289 0 1 1 29.7 31.3

OBES SURG (2013) 23:414–423 419

Table 2 (continued)

Author Year Surgery Sleep apnea Weight loss

Inc. Pre-op AHI Post-op AHI Persist Improve Resolve R + I Post-op BMI %EWL

Kehagias [6] 2011 LSG 0.2 0.67 0.67 29.6

Lakdawala [9] 2010 LSG 0 1 1 26.3

Omana [10] 2010 LSG 0.4 0.45 0.55 0.55 0.55 37.8 46.7

Silecchia [23] 2006 LSG 0.414 0.26 0.312 0.562 0.874 41.2

Wong [24] 2009 LSG 0.13 51

Abu-Abeid [25] 2001 AGB 0.167 0 1 1 30.5

Ahroni [26] 2005 AGB 0.315 0.362 0.638 32.3 28

Angrisani [7] 2007 AGB 0.037 0 1 1 34.9 97.9

Bowne [11] 2006 AGB 0.467 0.607 0.393 0.393 45.6

Dixon [27] 2005 AGB 1 61.6 13.4 0 0.16 0.84 1 37.2 105

Dolan [12] 2004 AGB 0.13 0.333 0 0.667 0.667 38.9

Frigg [28] 2004 AGB 0.36 0 0.25 0.75 1 34

Galvani [13] 2006 AGB 0.31 0.45 0.55 39

Himpens [29] 2011 AGB 0.026 0.077 33.79 92.82

Kasza [30] 2011 AGB 0.188 0.852 0.148 0.148 34

Korenkov [31] 2007 AGB 0.097 0 1 1 34

Lee [32] 2006 AGB 0.088 0 1 1 33.9 .94.7

Lettieri [33] 2008 AGB 1 47.9 24.5 0.083 0.875 0.042 0.917 32.1 .92.8

O’Brien [34] 2002 AGB 0.33 0.02 0.98

Omana [10] 2010 AGB 0.16 0.75 0.25 36

Parikh [35] 2006 AGB 0.075 0.857 0.857 27.3 72

Rubenstein [36] 2002 AGB 0.19 0 1 1 53.60

Spivak [37] 2005 AGB 0.018 0.67 0.33 0.33 34.9

Weiner [38] 2002 AGB 0.082 0.012 0.988 32

Yu [39] 2011 AGB 0.563 0 1 1 29.6 112

Wong [24] 2009 AGB 0.44 0.44 0.56 34

Bowne [11] 2006 GB 0.543 0.12 0.88 0.88 26.5

Brolin [14] 1992 GB 0.055 43 140

Brolin [14] 1992 GB 0 1 1 37 159

Cordera [40] 2004 GB 0.222 0.5 0.5 35 99

Fritscher [41] 2007 GB 1 46.5 16 0.25 0.25 0.5 0.75 34.1 100.7

Gagne [42] 2011 GB 0.22 0.04 0.22 0.74 0.96 34

Galvani[13] 2006 GB 0.2 0.63 65

Gonzalez [43] 2003 GB 0.17 1 66

Hamed [15] 2008 GB 0.232 0.556 0.444 0.444 79.7

Hamed [15] 2008 GB 0.466 0.375 0.25 0.25 59.3

Haines [44] 2006 GB 0.83 0.307 0.178 0.515 0.693 38

He [45] 2004 GB 0.197 0.02 0.13 0.85 0.98 63.9

Higa[46] 2011 GB 0.19 0.79 33.2 57.1

Huerta [47] 2007 GB 0.47 0.33 0.29 0.62 31

Kehagias [6] 2011 GB 0.1 0.67 0.67 31.3

Lakdawala [9] 2010 GB 0 1 1 31

Maher[48] 2007 GB 0.486 0.75

Nelson [49] 2006 GB 0.33 0.48 0.48 37

Nelson [50] 2006 GB 0.36 0.77 0.77 37

Pajecki [51] 2007 GB 0.425 0 0.065 0.935 1 34.5 80.2

Papasavas [52] 2002 GB 0.038 0 1 1 32.6 77

420 OBES SURG (2013) 23:414–423

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3. Buchwald H, Avidor Y, Braunwald E, et al. Bariatric surgery:a systematic review and meta-analysis. JAMA. 2004;292(14):1724–37.

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6. Kehagias I, Karamanakos SN, Argentou M, et al. Random-ized clinical trial of laparoscopic Roux-en-Y gastric bypass

Table 2 (continued)

Author Year Surgery Sleep apnea Weight loss

Inc. Pre-op AHI Post-op AHI Persist Improve Resolve R + I Post-op BMI %EWL

Papasavas [53] 2004 GB 0.1 0.86 67

Peluso [54] 2007 GB 0.24 0.25 0.75 73.4

Pinheiro [16] 2008 GB 0.19 0 1 1 70

Pinheiro [16] 2008 GB 0.125 0 1 1 74

Raftopoulos [19] 2005 GB 0.314 0.883 54.1

Raftopoulos [19] 2005 GB 0.57 0.8125 51.3

Schauer [55] 2000 GB 0.16 0.07 0.19 0.74 0.93 30.4 71.8

Skroubis [8] 2006 GB 0.046 0 1 1 28

Slotman [56] 2010 GB 1 0.86 57

Sosa [57] 2004 GB 0.13 0.67

Suter [58] 2011 GB 0.509 0.2 0.8 1 72.1

Tejirian [59] 2008 GB 0.26 0.08 0.45 0.53 63

Varela [60] 2007 GB 1 35 0.52 73

Wittgrove [61] 2000 GB 0.45 0.01 0.98 77

Wittgrove [62] 2009 GB 0.4 0.025 0.94

Yan [63] 2008 GB 0.47 0.6

Wong [24] 2009 GB 0.43 61

De Luis [64] 2005 BPD 0.158 0.67 35.6 13.7

Dolan [12] 2004 BPD 0.22 0.8 34.6 64.4

Simard [65] 2004 BPD 0.338 0.98 30.5

Skroubis [8] 2006 BPD 0.015 0 1 1 24.1 83.1

Busetto [66] 2005 MIX 1 59.3 14 0.41 0.59 0.59 48.6

Closset [67] 2004 MIX 0.2 0.02 0.3 0.68 0.98 30.7 91

Dhabuwala [68] 2000 MIX 0.076 0.083 0.917 1 28 71

Grunstein [17] 2007 MIX 0.24 0.083 0.279 0.638 0.917 32.5

Guardiano [69] 2003 MIX 1 55 14 0.375 0.625 1 34

Iannelli[70] 2009 MIX 0.27 0.5 0.5 1 33.1 64.6

Karason [18] 2000 MIX 0.23 0.08 0.65 32.5

Pillar [71] 1994 MIX 1 40 11 0.428 33

Scheuller [72] 2001 MIX 1 96.9 11.3 0.4 0.6 1

Sugerman [73] 1986 MIX 0.74 44 8 0.55 62

Sugerman [74] 1992 MIX 0.52 64 26 0.07 0.263 0.667 0.93 38 53

Inc incidence, R+I resolved or improved, AHI apnea–hypopnea index, BMI body mass index, EWL excess weight loss, AGB adjustable gastricbanding, GB Roux-en-Y gastric bypass, BPD biliopancreatic diversion, MIX combined results group

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