Introduction
Methods
Research Questions
Identifying Relevant Studies
Study Selection
Charting the Data
Collating, Summarizing, and Reporting the Results
Consultation Exercise
Definition/s of WR and IWL after BS
Characteristic | Unit/component/s | Examples |
---|---|---|
Definition | ||
WR | Using EWL% | |
Using nadir weight % | ||
Using nadir weight kg | ||
Using maximum WL | ||
Using pre-surgery weight | ||
Using any WR after remission | Any WR after T2DM remission [28] | |
Using any WR | Any WR [29] | |
Using BMI | ≥ 5 BMI kg/m2 points from nadir [30] | |
Increase in BMI > 35 kg/m2 after successful WL [31] | ||
IWL | Using EWL% | EWL of < 50% at 18 months [16] |
Prevalencea | ||
WR | ||
IWL |
What Is the Reported Prevalence of WR and IWL After BS?
Mechanisms of WR
Characteristic | Summary |
---|---|
Causes | |
Hormonal/metabolic | |
Dietary non-adherence | |
Physical inactivity | |
Mental health | |
Anatomic surgical failure | |
LAGB | Pouch distension [69] |
LSG | |
RYGB | |
Predictors | |
Prevention and management | |
Behavioral | |
Dietary | |
Pharmacological | FDA approved: phentermine, phentermine–topiramate extended release, liraglutide, bupropion/naltrexone |
Surgical (management only) | |
After failed LAGB | Conversion to LSG, RYGB, BPD/DS [99] |
After failed LSG | Conversion to RYGB, BPD/DS [17] |
After failed RYGB | Conversion to DRYGB or to BPD/DS; or revision of gastric pouch and anastomosis, revision with gastric band [100] |
Preoperative Predictors of WR and IWL Post-BS
Prevention and Management Strategies of WR and IWL After BS
Now What? Knowledge Gaps and Possible Way Forward
Knowledge gap | Extent of gapa | Summary of potential gap | |
---|---|---|---|
WR | IWL | ||
Inconsistent reporting | + + | + + + + | |
Lack of standardization | + + + | NA | |
Clinical significance | + + | ||
+ + + + | No data on clinical significance of IWL, urgently needed | ||
Limited data on | |||
Prevalence | + | ||
+ + + | |||
Mechanism/s | + + + | Small studies on WR | |
+ + + + | Very sparse data on mechanism/s of IWL | ||
Gut hormones | + + + | ||
+ + + + | Very few studies on gut hormones, leptin or PBH in relation to IWL | ||
Dietary non-adherence | + + + | ||
+ + + + | Virtually no prospective studies on associations of caloric intake, macronutrient composition, dietary non-adherence, and food indiscretion with IWL | ||
Physical in/activity | + + + | ||
+ + + + | Very sparse data on PA types, durations and levels, and their associations with IWL | ||
Mental health | + + + | ||
+ + + + | |||
Surgical | + | ||
+ + + + | Role of surgical causes in IWL practically not assessed | ||
Management | |||
Behavioral | + + + | ||
+ + + + | No prospective studies of patients with IWL | ||
Dietary | + + + | ||
+ + + + | No published data available on effects of dietary management in IWL | ||
Pharmacological | + + + | ||
+ + + + | |||
Surgical revision | + | Effects of surgical revision on weight usually assess WR and IWL combined [17]; no RCTs of the effects of various revisional surgeries on WR | |
+ + + + | No RCTs of the effects of various revisional surgeries on IWL (for failed LAGB, LSG, RYGB) [99] |
Topic area | Example |
---|---|
Defining the concept | Unit/s: What unit/s should be used to define WR/IWL? (e.g., nadir weight? EWL%?, kg?) |
Cutoff: Is there controlled (or acceptable) WR/IWL (e.g., 20–50 %WR from nadir after 2 years) and significant (or non-acceptable) WR/IWL? | |
Definition: What is an appropriate definition of significant WR/IWL post-BS? | |
Components: Should the appropriate definition be based solely on WR per se, or should it also incorporate element/s of the clinical implication/s resulting from WR/IWL? (e.g., recurrence of T2DM, HTN, dyslipidemia, deteriorated QoL?) | |
Prevalence | Based on the above, what is a “true” prevalence of WR/IWL after different types of BS? |
Separation: As WR and IWL have distinct definitions, should they be reported collectively or separately in future studies? | |
Mandatory reporting: Should WR/IWL be one of the standard WL outcomes in comparisons of short-, medium-, and long-term outcomes of different types of BS? | |
Clinical outcomes | Generalization: Do WR/IWL always lead to recurrence of comorbidities? (e.g., why not all patients with WR experience recurrence of T2DM?) |
Extent: What are the impact/s of WR/IWL on changes in the status of different comorbidities? | |
Patient/s: Is the extent of such impact/s different among patients (e.g., individualized to each patient)? | |
Comorbidity/ities: Does the recurrence of a particular comorbidity/ities (e.g., T2DM, HTN, dyslipidemia, OSA) represent a sensitive “indicator” of the impact of WR/IWL? | |
Predictors | Known: Does addressing known pre-op predictors prevent WR/IWL or change their clinical outcomes? (e.g., lower BMI, younger age, earlier surgery)? |
Unknown: Are there additional modifiable/non-modifiable pre-op predictors of WR/IWL than already known (e.g., ghrelin, leptin)? | |
Selection: Should such predictors guide the selection of the type of BS (e.g., malabsorptive surgery for higher BMI or patients with comorbidities such as T2DM)? | |
Mechanisms | Hormones: What is the precise role/s of various hormones (GLP-1, PPY, leptin) in WR and in IWL? |
Mental Health: What are the effect/s of maladaptive eating on WR/IWL (e.g., grazing, binge eating)? | |
Psychiatric conditions: How do pre- and postop psychiatric illness affect WR/IWL (relationship/e.g., direction of depression and WR)? | |
Physical activity: What is the precise role of PA in WR/IWL? How can PA be accurately assessed (e.g., discrepancy between objectively/subjectively measured PA) | |
Surgery: How can the primary surgical technique be improved to prevent WR/IWL (e.g., biliopancreatic limb length)? | |
Others: Are there other mechanisms that contribute to WR/IWL (e.g., exact role/s of gut microbiomes, bile acids)? | |
Management | |
Behavioral | Type and mode: What is the effectiveness of various types/modes of delivery of behavioral therapies (e.g., group vs individualized, face to face vs remote)? |
Timing: When should behavioral therapy be introduced to effectively prevent or treat WR/IWL (e.g., preventive at weight plateau vs management after WR)? | |
Pharmacological | Type and dose: What is the effectiveness of various medication to manage WR/IWL (e.g., type of medication, single vs combination, effective dose)? Timing: What is the optimal time for medication/s to be introduced (e.g., preventive at weight plateau vs management after WR)? |
Surgical | Revision type: What is the suitable type of revisional surgery for WR/IWL (e.g., better WL outcomes and lower complications)? |