Oral drug therapy following bariatric surgery: an overview of fundamentals,literature and clinical recommendations

Bariatric surgery is the most effective solution for severe obesity and obesity with comorbidities, and the number of patients going through bariatric surgery is rapidly and constantly growing. The modified gastrointestinal anatomy of the patient may lead to significant pharmacokinetic alterations in the oral absorption of drugs after the surgery; however, because of insufficient available literature and inadequate awareness of the medical team, bariatric surgery patients may be discharged from the hospital with insufficient instructions regarding their medication therapy. In this article, we aim to present the various mechanisms by which bariatric surgery may influence oral drug absorption, to provide an overview of the currently available literature on the subject, and to draw guidelines for the recommendations bariatric surgery patients should be instructed before leaving the hospital. To date, and until more robust data are published, it is essential to follow and monitor patients closely for safety and efficacy of their medication therapies, both in the immediate and distant time post‐surgery.     

Risk of completed suicide after bariatric surgery: a systematic review

Bariatric surgery is one of the most effective treatments for morbid obesity, and a large body of research indicates significant long‐term weight loss. While overall mortality decreases in patients who received bariatric surgery, a number of studies have shown that suicide rates are higher in bariatric patients than in control groups. The objective of this study was to present a systematic review of suicide mortality after bariatric surgery and calculate an estimate for the suicide rate. Literature researches of the databases PubMed, Web of Knowledge, PsychInfo, ScienceDirect and Google Scholar were conducted. Thirty studies concerning bariatric surgery and completed suicides met the inclusion criteria. We included 28 studies in the estimation of a suicide rate for the bariatric population. Only one study (Tindle et al.) put a main focus on suicide after bariatric surgery; this was therefore chosen as an adequate reference figure for comparison. The other 27 chosen studies were compared with World Health Organization data and the suicide rate reported by Tindle et al. Twenty‐three thousand eight hundred eighty‐five people were included in the analysis. In the literature, we found a total of 95 suicides when examining 190,000 person‐years of post‐bariatric surgery data. Little information was provided describing the reasons for suicide and the time‐point of these events after surgery. We estimated a suicide rate of 4.1/10,000 person‐years (95% confidence interval [3.2, 5.1]/10,000 person‐years). A comparison with Tindle et al. demonstrates that their rate is significantly higher than our estimate (P = 0.03). Bariatric surgery patients show higher suicide rates than the general population. Therefore, there is a great need to identify persons at risk and post‐operative psychological monitoring is recommended.     

The impact of bariatric surgery on quality of life: a systematic review and meta‐analysis

This study aims to review the obesity literature in order to assess the impact of bariatric surgery on quality of life and the between‐study variation by examining the standardized mean magnitude of effect in change in the levels of quality of life. The following databases EMBASE, PubMed, PsycINFO, CINAHL, the Cochrane Library and Web of Science were systematically searched for studies examining change in quality of life in adults receiving bariatric surgery for obesity. Seventy‐two studies were included with a total of 9,433 participants treated for obesity with bariatric surgery. The average impact of bariatric surgery on quality of life corresponded to an effect size of 0.88 (95% CI: 0.80–0.96), indicating that bariatric surgery has a significant positive influence on quality of life in general. The impact varied considerably across studies with bariatric surgery showing a significantly greater positive influence on physical quality of life compared to mental quality of life. Bariatric surgery is effective in improving quality of life, especially when looking at physical well‐being. Greater focus on the psychological well‐being of the person undergoing surgery for obesity may lead to a better post‐surgery prognosis for more people.     

Patient‐reported outcomes in bariatric surgery: a systematic review of standards of reporting

Bariatric surgery is increasingly being used to treat severe obesity, but little is known about its impact on patient‐reported outcomes (PROs). For PRO data to influence practice, well‐designed and reported studies are required. A systematic review identified prospective bariatric surgery studies that used validated PRO measures. Risk of bias in randomized controlled trials (RCTs) was assessed, and papers were examined for reporting of (i) who completed PRO measures; (ii) missing PRO data and (iii) clinical interpretation of PRO data. Studies meeting all criteria were classified as robust. Eighty‐six studies were identified. Of the eight RCTs, risk of bias was high in one and unclear in seven. Sixty‐eight different PRO measures were identified, with the Short Form (SF)‐36 questionnaire most commonly used. Forty‐one (48%) studies explicitly stated measures were completed by patients, 63 (73%) documented missing PRO data and 50 (58%) interpreted PRO data clinically. Twenty‐six (30%) met all criteria. Although many bariatric surgery studies assess PROs, study design and reporting is often poor, limiting data interpretation and synthesis. Well‐designed studies that include agreed PRO measures are needed with reporting to include integration with clinical outcomes to inform practice.     

Bariatric surgery for obese children and adolescents: a systematic review and meta‐analysis

The number of obese young people continues to rise, with a corresponding increase in extreme obesity and paediatric‐adolescent bariatric surgery. We aimed to (i) systematically review the literature on bariatric surgery in children and adolescents; (ii) meta‐analyse change in body mass index (BMI) 1‐year post‐surgery and (iii) report complications, co‐morbidity resolution and health‐related quality of life (HRQoL). A systematic literature search (1955–2013) was performed to examine adjustable gastric band, sleeve gastrectomy, Roux‐en‐Y gastric bypass or biliopancreatic diversions operations among obese children and adolescents. Change in BMI a year after surgery was meta‐analysed using a random effects model. In total, 637 patients from 23 studies were included in the meta‐analysis. There were significant decreases in BMI at 1 year (average weighted mean BMI difference: ?13.5 kg m^?2; 95% confidence interval [CI] ?14.1 to ?11.9). Complications were inconsistently reported. There was some evidence of co‐morbidity resolution and improvements in HRQol post‐surgery. Bariatric surgery leads to significant short‐term weight loss in obese children and adolescents. However, the risks of complications are not well defined in the literature. Long‐term, prospectively designed studies, with clear reporting of complications and co‐morbidity resolution, alongside measures of HRQol, are needed to firmly establish the harms and benefits of bariatric surgery in children and adolescents.     

The quality of systematic reviews/meta‐analyses published in the field of bariatrics: A cross‐sectional systematic survey using AMSTAR 2 and ROBIS

High‐quality systematic reviews (SR) and meta‐analyses (MA) are considered to be reliable sources of information. This study aims to assess the quality of studies published as SR or MA in the field of bariatrics in 2016 and 2017. We identified SR and MA in the field of bariatrics by searching electronic databases (MEDLINE, Embase, and Cochrane Database of Systematic Reviews). Eligible studies were those identified as SR/MA in the title/abstract, which aimed to assess any outcome in patients with morbid obesity undergoing or scheduled to undergo bariatric surgery. Two authors independently reviewed all titles and abstracts, assessed full texts of potentially eligible studies, and assessed the quality of included studies. Any discrepancies were resolved by the third reviewer. We evaluated the quality and risk of bias of each SR/MA using AMSTAR 2 checklist and ROBIS tool, respectively. Seventy‐eight of 4236 references met inclusion criteria and were assessed for their quality/risk of bias. The methodological quality of 99% of all papers was classified as “critically low.” A total of 6% of the studies were at low risk of bias, and 78% were assessed as being at high risk of bias. The methodological quality of studies published in 2016 and 2017 as SR/MA is highly unsatisfactory.     

The influence of bariatric surgery on oral drug bioavailability in patients with obesity: A systematic review

Anatomical changes in the gastrointestinal tract and subsequent weight loss may influence drug disposition and thus drug dosing following bariatric surgery. This review systematically examines the effects of bariatric surgery on drug pharmacokinetics, focusing especially on the mechanisms involved in restricting oral bioavailability. Studies with a longitudinal before‐after design investigating the pharmacokinetics of at least one drug were reviewed. The need for dose adjustment following bariatric surgery was examined, as well as the potential for extrapolation to other drugs subjected to coinciding pharmacokinetic mechanisms. A total of 22 original articles and 32 different drugs were assessed. The majority of available data is based on Roux‐en‐Y gastric bypass (RYGBP) (18 of 22 studies), and hence, the overall interpretation is more or less limited to RYGBP. In the case of the majority of studied drugs, an increased absorption rate was observed early after RYGBP. The effect on systemic exposure allows for a low degree of extrapolation, including between drugs subjected to the same major metabolic and transporter pathways. On the basis of current understanding, predicting the pharmacokinetic change for a specific drug following RYGBP is challenging. Close monitoring of each individual drug is therefore recommended in the early postsurgical phase. Future studies should focus on the long‐term effects of bariatric surgery on drug disposition, and they should also aim to disentangle the effects of the surgery itself and the subsequent weight loss.     

Oral Anticoagulant Use After Bariatric Surgery: A Literature Review and Clinical Guidance

Bariatric surgery may alter the absorption, distribution, metabolism, or elimination (disposition) of orally administered drugs via changes to the gastrointestinal tract anatomy, body weight, and adipose tissue composition. As some patients who have undergone bariatric surgery will need therapeutic anticoagulation for various indications, appropriate knowledge is needed regarding anticoagulant drug disposition and resulting efficacy and safety in this population. We review general considerations about oral drug disposition in patients after bariatric surgery, as well as existing literature on oral anticoagulation after bariatric surgery. Overall, available evidence on therapeutic anticoagulation is very limited, and individual drug studies are necessary to learn how to safely and effectively use the direct oral anticoagulants. Given the sparsity of currently available data, it appears most prudent to use warfarin with international normalized ratio monitoring, and not direct oral anticoagulants, when full-dose anticoagulation is needed after bariatric surgery.     

Skeletal effects of bariatric surgery: examining bone loss,potential mechanisms and clinical relevance

Bariatric surgery is the most effective therapeutic approach to morbid obesity, resulting in substantial weight loss and improved cardiometabolic profiles; however, a growing body of evidence suggests that bariatric procedures increase both skeletal fragility and the risk of related future fracture secondary to excessive bone loss. Prospective evidence shows that areal bone mineral density (BMD) assessed by dual energy X‐ray absorptiometry (DXA) declines by as much as 14% in the proximal femoral regions, including the femoral neck and total hip, 12 months postoperatively. Lumbar spine areal BMD outcomes show greater 12‐month postoperative variability across surgical procedures (?8 to +6%) and contrast with no change in volumetric BMD outcomes measured by quantitative computed tomography. Diminished mechanical loading, micronutrient deficiency and malabsorption, along with neurohormonal alterations, offer plausible underlying mechanisms to explain these observed post‐bariatric bone changes, but most remain largely unsubstantiated in this population. Importantly, DXA‐based skeletal imaging may have limited utility in accurately detecting bone change in people undergoing bariatric surgery; partly because excessive tissue overlying bone increases the variability of areal BMD outcomes. Moreover, a paucity of fracture and osteoporosis incidence data raises questions about whether marked post‐bariatric surgery bone loss is clinically relevant or a functional adaptation to skeletal unloading. Future studies that use technology which is able to accurately capture the site‐specific volumetric BMD and bone architectural changes that underpin bone strength in people undergoing bariatric surgery, that consider mechanical load, and that better quantify long‐term fracture and osteoporosis incidence are necessary to understand the actual skeletal effects of bariatric surgery.     

A meta‐analysis of the effects of bariatric surgery on fracture risk

Bariatric surgery effectively treats morbid obesity. However, the negative effect of this surgery on the bone is concerning. The aim of this meta‐analysis was to investigate the fracture risk associated with bariatric surgery in morbidly obese subjects. Relevant studies published from database inception to September 2017 were identified in PubMed, Embase and the Cochrane Library. The Newcastle‐Ottawa Scale was used to evaluate the quality of the observational studies, and the Jadad score evaluated randomized controlled trials. Among the 1003 studies initially identified, five observational trials and one randomized controlled trial were eligible for inclusion. All studies included in the meta‐analysis were considered high quality. Risk for any type of fracture was higher in the surgical group than in the non‐surgical group (risk ratio [RR] 1.29, 95% confidence interval [CI] 1.18–1.42). After surgery, the fracture risk in non‐vertebral sites was significantly increased, especially in the upper limbs (RR 1.42, 95% CI 1.08–1.87; and RR 1.68, 95% CI 1.15–2.45). Compared with those with restrictive procedures, subjects who underwent mixed restrictive and malabsorptive procedures tended to have an increased fracture risk (RR 1.54, 95% CI 0.96–2.46). To conclude, bariatric surgery is associated with an increased risk of total and non‐vertebral fractures, especially in the upper limbs.     

Bariatric surgery and its impact on cardiovascular disease and mortality: A systematic review and meta-analysis

Background

Bariatric surgery has been shown to improve cardiovascular risk factors but long term benefits for survival and cardiovascular events are still uncertain.

Methods

We searched MEDLINE and EMBASE for parallel group studies that evaluated the clinical outcomes associated with bariatric surgery as compared to non-surgical treatment. Relevant studies were pooled using random effects meta-analysis for risk of myocardial infarction, stroke, cardiovascular events and mortality.

Results

14 studies met the inclusion criteria, which included 29,208 patients who underwent bariatric surgery and 166,200 nonsurgical controls (mean age 48 years, 30% male, follow up period ranged from 2 years to 14.7 years). Four studies were considered at moderate–high risk of bias, whilst ten studies were at moderate or lower risk of bias. Compared to nonsurgical controls there was more than 50% reduction in mortality amongst patients who had bariatric surgery (OR 0.48 95% CI 0.35–0.64, I² = 86%, 14 studies). In pooled analysis of four studies with adjusted data, bariatric surgery was associated with a significantly reduced risk of composite cardiovascular adverse events (OR 0.54 95% CI 0.41–0.70, I² = 58%). Bariatric surgery was also associated with significant reduction in specific endpoints of myocardial infarction (OR 0.46 95% CI 0.30–0.69, I² = 79%, 4 studies) and stroke (OR 0.49 95% CI 0.32–0.75, I² = 59%, 4 studies).

Conclusions

Data from observational studies indicates that patients undergoing bariatric surgery have a reduced risk of myocardial infarction, stroke, cardiovascular events and mortality compared to non-surgical controls. Future randomized studies should investigate whether these observations are reproduced in a clinical trials setting.     

Food addiction and bariatric surgery: a systematic review of the literature

Emerging research suggests that rates of food addiction are high among individuals seeking bariatric surgery, but little is known about associated features and the prognostic significance of pre‐operative food addiction. Thus, this article provides a systematic review and synthesis of the literature on food addiction and bariatric surgery. Articles were identified through PubMed and SCOPUS databases, resulting in a total of 19 studies which assessed food addiction among pre‐bariatric and/or post‐bariatric surgery patients using the Yale Food Addiction Scale. Most studies were cross‐sectional, and only two studies prospectively measured food addiction both pre‐operatively and post‐operatively. The presence of pre‐surgical food addiction was not associated with pre‐surgical weight or post‐surgical weight outcomes, yet pre‐surgical food addiction was related to broad levels of psychopathology. The relationship between food addiction and substance misuse among individuals undergoing bariatric surgery is mixed. In addition, very few studies have attempted to validate the construct of food addiction among bariatric surgery patients. Results should be interpreted with caution due to the methodological limitations and small sample sizes reported in most studies. Future rigorous research with larger and more diverse samples should prospectively examine the clinical utility and validity of the food addiction construct following bariatric surgery.     

Effects of bariatric surgery for knee complaints in (morbidly) obese adult patients: a systematic review

Obesity is a major risk factor for the development of knee osteoarthritis, and over the past 30 years the prevalence of obesity has more than doubled. In an advanced‐stage knee osteoarthritis is treated with total knee arthroplasty, and the demand for primary total knee arthroplasties is expected to grow exponentially. However, total knee arthroplasty in obese patients is associated with more complications, longer hospital stay and higher costs. We aimed to determine the effects of bariatric surgery on knee complaints in (morbidly) obese (body mass index >30 kg m^?2) adult patients. The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, TRIP, BIOSIS‐Previews and reference lists of retrieved publications were systematically searched from earliest available up to 20 April 2014 for any English, German, French and Dutch studies. There was no restriction on study design. We included studies on the effect of surgically induced weight reduction on knee complaints in (morbidly) obese adult patients, with a minimal follow‐up of 3 months. Studies on the effects of lipectomy or liposuction and studies in which patients had already received a total knee arthroplasty were excluded. Thirteen studies were included in this systematic review with a total of 3,837 patients. Although different assessment tools were used, an overall significant improvement in knee pain was seen in 73% out of the used assessments. All studies measuring intensity of knee pain, knee physical function and knee stiffness showed a significant improvement after bariatric surgery. The quality of evidence was very low or too low for most of the included studies and moderate for one study. Bariatric surgery with subsequent marked weight loss is likely to improve knee pain, physical function and stiffness in (morbidly) obese adult patients. However, with the current available evidence, there is need for high‐quality studies.     

Is social support associated with greater weight loss after bariatric surgery?: a systematic review

Social support may be associated with increased weight loss after bariatric surgery. The objective of this article is to determine impact of post‐operative support groups and other forms of social support on weight loss after bariatric surgery. MEDLINE search (1988–2009) was completed using MeSH terms including bariatric procedures and a spectrum of patient factors with potential relationship to weight loss outcomes. Of the 934 screened studies, 10 reported on social support and weight loss outcomes. Five studies reported on support groups and five studies reported on other forms of social support (such as perceived family support or number of confidants) and degree of post‐operative weight loss (total n = 735 patients). All studies found a positive association between post‐operative support groups and weight loss. One study found a positive association between marital status (being single) and weight loss, while three studies found a non‐significant positive trend and one study was inconclusive. Support group attendance after bariatric surgery is associated with greater post‐operative weight loss. Further research is necessary to determine the impact of other forms of social support. These factors should be addressed in prospective studies of weight loss following bariatric surgery, as they may represent ways to improve post‐operative outcomes.     

Microvascular complications of obesity and diabetes—Role of bariatric surgery

Bariatric surgery in people with obesity can lead to long-term remission of type 2 diabetes mellitus (T2DM) and a reduction in the incidence of macrovascular complications. The impact of bariatric surgery on microvascular complications is less clear. In this narrative review, we sought to evaluate the effect of bariatric surgery on microvascular complications in patients with and without diabetes. The risk of developing microvascular complications is increased in people with obesity, and this is amplified in those with T2DM. The impact of metabolic surgery on microvascular complications is limited to a subgroup analysis of studies or statistical modeling to predict the glycemia-independent effect of bariatric surgery. While bariatric surgery halts the progression of retinopathy in those with minimal retinopathy, it may worsen in those with advanced retinopathy. Bariatric surgery improves proteinuria and major renal outcomes, regardless of the severity of renal impairment. Bariatric surgery in patients with obesity with or without diabetes is associated with an improvement in neuropathic symptoms and regeneration of small nerve fibers. In conclusion, bariatric surgery is associated with an improvement in microvascular complications. Further studies are needed to elucidate the underlying mechanisms for the favorable effect of bariatric surgery on microvascular outcomes.     

Current status of bariatric surgery in the treatment of type 2 diabetes

Bariatric surgery (from the Greek words baros meaning ‘weight’ and iatrikos‘the art of healing’) is a rapidly evolving branch of surgical science. The aim is to induce major weight loss in those whose obesity places them at high risk of serious health problems. In an attempt to balance the risks of surgery against the benefits of weight loss, bariatric operations are currently performed only in the morbidly obese, or those with a body mass index (BMI) > 35 kgm^?2 who already have developed comorbidity such as type 2 diabetes. Although weight loss is beneficial for obese patients with diabetes, current medical treatment for obesity is difficult. In contrast, observational studies show a major impact of bariatric surgery on diabetes, raising the question whether this approach should be used more widely to treat diabetes in obese patients? If bariatric surgery were shown to be the best way to treat diabetes in obese subjects the implications for health services would be wide‐ranging. Bariatric surgery leads to withdrawal of diabetic treatment in about 60% or more of patients, and reductions of therapy for many others. Although data on bariatric surgery in subjects with diabetes are provocative, most studies have been uncontrolled or flawed in other ways. Most importantly, bariatric surgery has not yet been compared against standard medical treatment for diabetes in randomized controlled trials with diabetes‐specific endpoints in all relevant patient groups. Potential indications for bariatric surgery are discussed, and the unanswered questions that need to be addressed by clinical trials are summarized. Although small numbers of patients may be interested in bariatric surgery for type 2 diabetes, current data are insufficient to endorse its wide scale use for this indication. Until essential studies are undertaken the role and economics of bariatric surgery in the diabetic clinic will remain uncertain.     

Effect of bariatric surgery on cardiovascular risk profile

Obesity is associated with increased risk for cardiovascular (CV) disease (CVD) and CV mortality. Bariatric surgery has been shown to resolve or improve CVD risk factors, to varying degrees. The objective of this systematic review was to determine the impact of bariatric surgery on CV risk factors and mortality. A systematic review of the published research was performed to evaluate evidence regarding CV outcomes in morbidly obese bariatric patients. Two major databases (PubMed and the Cochrane Library) were searched. The review included all original reports reporting outcomes after bariatric surgery, published in English, from January 1950 to July 2010. In total, 637 studies were identified from the initial screen. After applying inclusion and exclusion criteria, 52 studies involving 16,867 patients were included (mean age 42 years, 78% women). The baseline prevalence of hypertension, diabetes, and dyslipidemia was 49%, 28%, and 46%, respectively. Mean follow-up was 34 months (range 3 to 155), and the average excess weight loss was 52% (range 16% to 87%). Most studies reported significant decreases postoperatively in the prevalence of CV risk factors, including hypertension, diabetes, and dyslipidemia. Mean systolic pressure reduced from to 139 to 124 mm Hg and diastolic pressure from 87 to 77 mm Hg. C-reactive protein decreased, endothelial function improved, and a 40% relative risk reduction for 10-year coronary heart disease risk was observed, as determined by the Framingham risk score. In conclusion, this review highlights the benefits of bariatric surgery in reducing or eliminating risk factors for CVD. It provides further evidence to support surgical treatment of obesity to achieve CVD risk reduction.     

Impact of bariatric surgery on serum uric acid levels and the incidence of gout—A meta‐analysis

Gout is characterized by high serum uric acid (SUA) levels and arthritis. It is associated with obesity and metabolic syndrome. Bariatric surgery has been associated with decreased SUA levels and overall gout incidence. This meta‐analysis aims to summarize the current evidence on bariatric surgery, gout and SUA levels. A literature review was performed on papers published from 2000 up till December 2018. Original studies investigating the impact of bariatric surgery on SUA levels or gout incidence were evaluated. Twenty studies with a total of 5,233 patients were analysed. Majority (n=14) had a follow‐up duration of at least 12 months. The mean preoperative body mass index (BMI) was 45.2kg m^?2. The mean preoperative SUA level was 6.5mg dL^?1. Subgroup analysis demonstrated a mean decrease in SUA levels (?0.73mg dL^?1) from the third postoperative month onwards, which was sustained until the third postoperative year (?1.91mg dL^?1). There was a rise in SUA levels in the first post‐operative month. Meta‐regression analyses demonstrated a proportionate linear relationship between the change in BMI and SUA levels. Post‐bariatric surgery weight loss is associated with reduced SUA levels and decreased incidence of gout attacks. However, this is only evident from the third post‐operative month onwards.     

Binge Eating,Binge Eating Disorder and Loss of Control Eating: Effects on Weight Outcomes after Bariatric Surgery

There is increasing evidence that patients who have problems with binge eating (BE) or BE disorder (BED) are quite common among the severely obese, including bariatric surgery candidates. The literature suggests that in many cases such eating behaviours improve after bariatric surgery, although this is not uniformly true. The current paper reviews the data on the development of BE, BED and loss of control (LOC) eating after bariatric surgery and the impact of these problems on long‐term weight outcome. A search was made of various databases regarding evidence of BE, BED and LOC eating post‐operatively in bariatric surgery patients. The data extracted from the literature suggests that 15 research studies have now examined this question. Fourteen of the available 15 studies suggest that the development of problems with BE, BED or LOC eating post‐bariatric surgery is associated with less weight loss and/or more weight regain post‐bariatric surgery. These data suggests that it is important to identify individuals at high risk for these problems, to follow them post‐operatively, and, if appropriate interventions can be developed if such behaviours occur in order to maximize weight loss outcomes. Copyright © 2013 John Wiley & Sons, Ltd and Eating Disorders Association.     

Impact of bariatric surgery on physical functioning in obese adults

Obesity is associated with a profound impairment in the ability to perform the basic physical activities required for everyday function. This impacts on quality of life and contributes to disability. Bariatric surgery leads to weight loss and metabolic improvements in severe obesity; however, less is known about its effect on physical functioning. This narrative review summarizes current evidence on the effect of bariatric surgery on this outcome with a consideration of the mechanisms involved. Nine longitudinal observational studies reporting objective measures of physical functioning were identified. Inclusion criteria, follow‐up time and outcomes reported varied considerably between studies and sample sizes were small. They all showed a significant improvement in performance following surgery despite variations in baseline patient characteristics. Additionally, six studies were found in which subjects were subjected to exercise testing protocols. Performance of the test protocol improved in all. Where reported, peak oxygen uptake related to body weight improved; however, absolute values were either unchanged or decreased. In conclusion, observational evidence suggests that patients’ physical functioning improves following bariatric surgery. More evidence is required regarding mechanisms involved; however, it may be due to improved efficiency in performing activities as opposed to absolute improvements in cardiorespiratory or muscle function.