Review of meta-analytic comparisons of bariatric surgery with a focus on laparoscopic adjustable gastric banding

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Abstract

Background

In a prior systematic review and meta-analysis of the large body of literature describing the laparoscopic adjustable gastric band (LAGB), outcomes for the Swedish Adjustable Gastric Band (SAGB) and Lap-Band (LB), in particular, were reviewed. This article summarizes those results and discusses them in relation to the 3 other published bariatric surgery meta-analyses (JAMA 2004;292:1724–37; Ann Intern Med 2005;142:547–59; and Surgery 2007;142:621–32).

Methods

In the gastric banding meta-analysis, systematic review included screening of 4,594 studies published in any language (Jan 1, 1998–April 30, 2006). Studies with at least 10 SAGB or LB patients reporting ≥30-day efficacy or safety outcomes were eligible for review; data were extracted from accepted studies. Weighted means analysis and random-effects meta-analysis of efficacy outcomes of interest were conducted.

Results

In the gastric banding meta-analysis, 129 studies (patients n = 28,980) were accepted (33 SAGB/104 LB studies). In 4,273 patients (36 treatment groups) in 33 SAGB studies, and in 24,707 patients (111 groups) in 104 LB studies, mean baseline age (39.1–40.2 yrs), body mass index ([BMI] 43.8–45.3 kg/m2), and sex (females 79.2%–82.5%) were similar. Three-year mean SAGB/LB excess weight loss (56.36%/50.20%) was significant, as was resolution of type 2 diabetes (61.45%/60.29%) and hypertension (62.95%/43.58%) (P < .05). Adverse event (AE) rates appeared comparable, and early mortality was equivalent (≤.1%).

Discussion

In the SAGB and LB meta-analysis at 1, 2, and 3 years, weight loss, resolution of diabetes and hypertension, and adverse events appeared equivalent. All meta-analyses that assessed weight loss found that bariatric surgery produced clinically significant reductions in excess weight across procedures in the short term. One meta-analysis found that bariatric surgery produced significantly more weight loss than medical treatment in patients with BMI >40 kg/m2 in the short term, with malabsorptive procedures producing the greatest weight loss. All studies reporting on comorbidities showed significant resolution or improvement of type 2 diabetes mellitus ([T2DM] ≥60%), hypertension (≥43%), and dyslipidemia (≥70%). In one meta-analysis, surgery was found to be superior to medical therapy in resolving T2DM, hypertension, and dyslipidemia. Sleep apnea was significantly resolved/improved in ≥85% across procedures in the one meta-analysis that addressed this comorbidity. One meta-analysis found no differences in AEs between procedures; however, the laparoscopic approach was associated with significantly reduced AEs. In the 4 meta-analyses, mortality was low (.1%–1.11%) for all procedures. Bariatric surgery was observed to be a safe and highly effective therapy for morbid obesity. Heterogeneity in nomenclature, study methods, statistical detail, definitions of weight-loss success and comorbid disease resolution, and completeness of data sets did not allow for comparison of some variables. Initiatives including the Iowa Bariatric Surgery Registry (IBSR), the Longitudinal Assessment of Bariatric Surgery (LABS) consortium, the Surgical Review Corporation (SRC) Center of Excellence initiative, and the Bariatric Outcomes Longitudinal Database [BOLD] are working to improve data standardization, which, in turn, will facilitate summary and comparison of bariatric surgery outcomes.

Introduction

In 2007, at the International Federation of Surgery for Obesity (IFSO) symposium in Porto, Portugal, a summary of our systematic review and meta-analysis of worldwide Swedish Adjustable Gastric Band and Lap-Band literature was presented. The highlights of that presentation are given here, as a synopsis of the original study results (published in March 2008 in the journal of Surgery for Obesity and Related Diseases[1]), with a new Discussion, in which the findings of the current meta-analysis are considered in the context of the 3 other published bariatric surgery meta-analyses (i.e., Buchwald et al., 2004 [2]; Maggard et al., 2005 [3]; Buchwald et al., 2007 [4]).

Laparoscopic adjustable gastric banding (LAGB) is the dominant bariatric procedure outside of the United States, and its popularity is rising in America. The gastric bands available globally include the Swedish Adjustable Gastric Band ([SAGB] Obtech Medical Sarl, Le Locle, Switzerland, and Ethicon Endo-Surgery, Inc, Cincinnati, OH); Lap-Band ([LB] Allergan, Irvine, CA); AMI Band (Agency for Medical Interventions, Feldkirch, Austria); Heliogast Adjustable Gastric Ring (Hélioscopie, Vienne Cedex, France); Midband (Médical Innovation Dévelopment, Limonest, France); and the MiniMizer (HospiMedical, GmbH, Meerbusch, Germany). Meta-analysis of LAGB was undertaken to compare the 2 most used and widely studied bands available, the SAGB and LB, introduced in the mid 1980s by Hallberg and Forsell (1985) [5] and Kuzmak (1986) [6], respectively. The LAGB meta-analysis sought to assess the efficacy and safety of gastric banding as a therapeutic strategy and to compare SAGB and LB in terms of weight loss, comorbidity improvement, and adverse events (AEs). (The SAGB is available in the United States as the Realize Band).

Section snippets

Sources

On July 7, 2003, a prospective protocol was developed to undertake systematic review of the medical literature to meta-analytically compare SAGB and LB outcomes [7]. A broad electronic search was performed via PubMed accessing MEDLINE, Current Contents, and the Cochrane Library with cut-off dates of January 1, 1998 to April 30, 2006. The following search terms were employed: Obesity/surgery [MeSH] OR gastroplasty OR bariatric OR “gastric banding” with the delimitation: “Human, 1998–2006.”

Screening outcomes

Of the complete catalogue of SAGB and LB citations identified (n = 4,594), level-1 screening rejected 2,740 studies; of the remaining 1,854 studies, 1,549 were rejected in level-2 screening. Of 305 remaining studies, 176 were kin studies whose data were counted only once in amalgamation with the overlapping data of the 129 “accepted studies” (patient n = 28,980), all of which were fully extracted and eligible for meta-analysis.

Study characteristics

Accepted studies included 83 from Europe (patient n = 18,416), 22

Discussion

The above synopsis of the gastric banding meta-analysis describes the first systematic review of the world literature (4,594 citations) to encompass the cumulative studies of the 2 most commonly used LAGBs. Designs of the accepted studies were varied and ranged from several randomized controlled clinical trials to, primarily, single-center retrospective observational series. For both bands, independently, meta-analysis found significant efficacy and safety that appeared equivalent for the

Conclusion

The maturation of broadly conceived data management initiatives will, in time, provide practical solutions that greatly reduce the data summary challenges inherent in the bariatric literature. As these meta-analyses demonstrate, the literature is an enduring record that currently features the varied methods of data compilation, analysis, and reporting used since the field's inception; although many studies in this literature are methodologically strong individually, the variance in data

Disclosures

Dr. Cunneen is a consultant for Ethicon Endo-Surgery; his expenses for the symposium and an honorarium were paid by Ethicon Endo-Surgery, Inc., the manufacturer of the Realize Band (also known as the Swedish Adjustable Gastric Band).

Acknowledgment

The author acknowledges and thanks United BioSource Corporation, Medford, MA (formerly Metaworks, Inc.) for the statistical analysis performed for the original gastric banding meta-analysis.

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