Weight Loss Results and Compliance with Follow-up after Bariatric Surgery

Purpose: The importance of follow-up (FU) for midterm weight loss (WL) after bariatric surgery is controversial. Compliance to this FU remains challenging. Several risk factors for loss to FU (LtFU) have been mentioned. The aim was therefore to evaluate the association between WL and LtFU 3 to 5 years postoperatively and to identify risk factors for LtFU. Materials and Methods: A single-center cross-sectional study in the Netherlands. Between June and October 2018, patients scheduled for a 3-, 4-, or 5-year FU appointment were included into two groups: compliant (to their scheduled appointment and overall maximally 1 missed appointment) and non-compliant (missed the scheduled appointment and at least 1 overall). Baseline, surgical, and FU characteristics were collected and a questionnaire concerning socio-economic factors. Results: In total, 217 patients in the compliant group and 181 in the non-compliant group were included with a median body mass index at baseline of 42.0 and 42.9 respectively. Eighty-eight percent underwent a laparoscopic Roux-en-Y gastric bypass. The median percentage total weight loss for the compliant and non-compliant groups was 30.7% versus 28.9% at 3, 29.3% versus 30.2% at 4, and 29.6% versus 29.9% at 5 years respectively, all p>0.05. Age, persistent comorbidities and vitamin deficiencies, a yearly salary <20,000 euro, no health insurance coverage, and not understanding the importance of FU were risk factors for LtFU. Conclusion: Three to 5 years postoperatively, there is no association between LtFU and WL. The compliant group demonstrated more comorbidities and vitamin deficiencies. Younger age, not understanding the importance of FU, and financial challenges were risk factors for LtFU. Graphical abstract: [Figure not available: see fulltext.

Is Adherence to Follow-Up After Bariatric Surgery Necessary? A Systematic Review and Meta-Analysis

The association of adherence to follow-up (FU) after laparoscopic gastric bypass — and gastric sleeve with weight loss (WL) is unclear. The aim of this study was to evaluate this association. Fourteen full text articles were included in the systematic review. Eight studies were included in the meta-analysis concerning FU up to 3 years postoperatively and 3 for the FU between 3 and 10 years postoperatively. Results showed a significant association between adherence to FU 0.5 to 3 years postoperatively and percentage excess WL (%EWL) but did not demonstrate a significant association between FU > 3 years postoperatively and total WL (%TWL). In conclusion, adherence to FU may not be associated with WL and therefore stringent lifelong FU in its current form should be evaluated

Artificial Intelligence in Bariatric Surgery: Current Status and Future Perspectives

Background: Machine learning (ML) has been successful in several fields of healthcare, however the use of ML within bariatric surgery seems to be limited. In this systematic review, an overview of ML applications within bariatric surgery is provided. Methods: The databases PubMed, EMBASE, Cochrane, and Web of Science were searched for articles describing ML in bariatric surgery. The Cochrane risk of bias tool and the PROBAST tool were used to evaluate the methodological quality of included studies. Results: The majority of applied ML algorithms predicted postoperative complications and weight loss with accuracies up to 98%. Conclusions: In conclusion, ML algorithms have shown promising capabilities in the prediction of surgical outcomes after bariatric surgery. Nevertheless, the clinical introduction of ML is dependent upon the external validation of ML

Sample size of surgical randomized controlled trials : a lack of improvement over time

Background: Interpretation of randomized controlled trials (RCTs) without a significant difference regarding the primary outcome (negative RCTs) is frequently challenging, due to concerns about sample size and thus sufficient statistical power. We aimed to assess the adequacy of sample size and corresponding power of surgical RCTs. Methods: We previously identified all surgical RCTs available in PubMed in two distinct years a decade apart (1999 and 2009). For all “negative” trials, we estimated whether the sample size of the trial was appropriate to detect a difference in the primary outcome measure. The main outcome measure was a sufficient sample size to detect large, medium, and small treatment effects. We also performed a post hoc power analysis based on the actual observed effect difference. Results: A total of 228 negative RCTs (74 in 1999 and 121 in 2009) were included. The median sample size was 76 (± 222) and 80 (± 163) in 1999 and 2009, respectively. Sample size calculation was increasingly reported from 40% in 1999 to 54% in 2009 (P = 0.02). The proportion of studies adequately powered to detect large (57% versus 68%), medium (26% versus 25%), or small (8% versus 7%) differences did not differ significantly between 1999 and 2009, respectively. To reach sufficient power, the required increases in sample size were 130%, 240%, and 1032% for large, medium, and small differences, respectively. Reporting a sample size calculation was the only independent predictor for adequate power. Conclusions: Despite slight improvement in the reporting of a sample size calculation, about a third of surgical trials remains underpowered to demonstrate differences that are likely to be clinically significant. Increased attention of researchers, medical ethical boards, and journal editors is required to reduce potentially wasted resources on underpowered trials

Journal impact factor and methodological quality of surgical randomized controlled trials: an empirical study

The journal impact factor (IF) is often used as a surrogate marker for methodological quality. The objective of this study is to evaluate the relation between the journal IF and methodological quality of surgical randomized controlled trials (RCTs). Surgical RCTs published in PubMed in 1999 and 2009 were identified. According to IF, RCTs were divided into groups of low ( 3), as well as into top-10 vs all other journals. Methodological quality characteristics and factors concerning funding, ethical approval and statistical significance of outcomes were extracted and compared between the IF groups. Additionally, a multivariate regression was performed. The median IF was 2.2 (IQR 2.37). The percentage of 'low-risk of bias' RCTs was 13% for top-10 journals vs 4% for other journals in 1999 (P <0.02), and 30 vs 12% in 2009 (P <0.02). Similar results were observed for high vs low IF groups. The presence of sample-size calculation, adequate generation of allocation and intention-to-treat analysis were independently associated with publication in higher IF journals; as were multicentre trials and multiple authors. Publication of RCTs in high IF journals is associated with moderate improvement in methodological quality compared to RCTs published in lower IF journals. RCTs with adequate sample-size calculation, generation of allocation or intention-to-treat analysis were associated with publication in a high IF journal. On the other hand, reporting a statistically significant outcome and being industry funded were not independently associated with publication in a higher IF journa

Perioperative management of obstructive sleep apnea in bariatric surgery: a consensus guideline

BACKGROUND: The frequency of metabolic and bariatric surgery (MBS) is increasing worldwide, with over 500,000 cases performed every year. Obstructive sleep apnea (OSA) is present in 35%-94% of MBS patients. Nevertheless, consensus regarding the perioperative management of OSA in MBS patients is not established. OBJECTIVES: To provide consensus based guidelines utilizing current literature and, when in the absence of supporting clinical data, expert opinion by organizing a consensus meeting of experts from relevant specialties. SETTING: The meeting was held in Amsterdam, the Netherlands. METHODS: A panel of 15 international experts identified 75 questions covering preoperative screening, treatment, postoperative monitoring, anesthetic care and follow-up. Six researchers reviewed the literature systematically. During this meeting, the "Amsterdam Delphi Method" was utilized including controlled acquisition of feedback, aggregation of responses and iteration. RESULTS: Recommendations or statements were provided for 58 questions. In the judgment of the experts, 17 questions provided no additional useful information and it was agreed to exclude them. With the exception of 3 recommendations (64%, 66%, and 66% respectively), consensus (>70%) was reached for 55 statements and recommendations. Several highlights: polysomnography is the gold standard for diagnosing OSA; continuous positive airway pressure is recommended for all patients with moderate and severe OSA; OSA patients should be continuously monitored with pulse oximetry in the early postoperative period; perioperative usage of sedatives and opioids should be minimized. CONCLUSION: This first international expert meeting provided 58 statements and recommendations for a clinical consensus guideline regarding the perioperative management of OSA patients undergoing MBS.status: publishe

Perioperative management of obstructive sleep apnea in bariatric surgery : a consensus guideline

Background: The frequency of metabolic and bariatric surgery (MBS) is increasing worldwide, with over 500,000 cases performed every year. Obstructive sleep apnea (OSA) is present in 35%–94% of MBS patients. Nevertheless, consensus regarding the perioperative management of OSA in MBS patients is not established. Objectives: To provide consensus based guidelines utilizing current literature and, when in the absence of supporting clinical data, expert opinion by organizing a consensus meeting of experts from relevant specialties. Setting: The meeting was held in Amsterdam, the Netherlands. Methods: A panel of 15 international experts identified 75 questions covering preoperative screening, treatment, postoperative monitoring, anesthetic care and follow-up. Six researchers reviewed the literature systematically. During this meeting, the “Amsterdam Delphi Method” was utilized including controlled acquisition of feedback, aggregation of responses and iteration. Results: Recommendations or statements were provided for 58 questions. In the judgment of the experts, 17 questions provided no additional useful information and it was agreed to exclude them. With the exception of 3 recommendations (64%, 66%, and 66% respectively), consensus (>70%) was reached for 55 statements and recommendations. Several highlights: polysomnography is the gold standard for diagnosing OSA; continuous positive airway pressure is recommended for all patients with moderate and severe OSA; OSA patients should be continuously monitored with pulse oximetry in the early postoperative period; perioperative usage of sedatives and opioids should be minimized. Conclusion: This first international expert meeting provided 58 statements and recommendations for a clinical consensus guideline regarding the perioperative management of OSA patients undergoing MBS