Single-stage revision from gastric band to gastric bypass or sleeve gastrectomy: 6- and 12-month outcomes

Five-year outcomes of revisional bariatric surgery: gastric band to sleeve gastrectomy or to Roux-en-Y gastric bypass

BACKGROUND

Revisional bariatric surgery after an index adjustable gastric band (AGB) may be indicated to remedy weight relapse or band-related complications. We examined outcomes five years following revision from AGB to laparoscopic sleeve gastrectomy (AGB-LSG) or to Roux-en-Y gastric bypass (AGB-RYGB).

METHODS

We conducted a retrospective review to identify patients (men and women, age 18-80) who underwent one revisional bariatric procedure with AGB as the index procedure at two medical centers in our healthcare system between January 2012 and February 2017. We only included patients with a pre-revision BMI > 30 kg/m2 for whom 5-year follow-up data were available. We compared 5-year weight loss and remission of comorbidities in patients undergoing AGB-LSG and AGB-RYGB conversion.

RESULTS

A total of 114 patients met inclusion criteria (65 AGB-LSG, 49 AGB-RYGB). At 5-year post-revision, percent total weight loss (3.4% vs 19.9%; p < 0.001), percent excess weight loss (7.0% vs 50.8%; p < 0.001) and decrease in BMI (1.5 vs 8.8; p < 0.001) was greater in AGB-RYGB vs. AGB-LSG. No significant difference in remission or development of new comorbidities was observed.

CONCLUSION

Conversion of AGB to RYGB is associated with superior intermediate-term weight loss compared to conversion of AGB to LSG. Future multicenter studies with larger sample sizes are necessary to further describe the intermediate-term outcomes of revisional bariatric surgery.

Roux-en-Y Gastric Bypass as Conversion Procedure of Failed Gastric Banding: Short-Term Outcomes of 1295 Patients in One Single Center

PURPOSE

Laparoscopic adjustable gastric band (LAGB) has high technical and weight loss failure rates. We evaluate here the 1-year morbidity, mortality, and weight loss of laparoscopic Roux-en-Y-gastric bypass (LRYGB) as a feasible conversion strategy.

METHODS

Patients with a failed primary LAGB who underwent LRYGB from July 2004 to December 2019 were selected from an electronic database at our center. Patients had a conversion to LRYGB at the same time (one-stage approach) or with a minimum of 3 months in between (two-stage approach). Primary outcomes included 30-day morbidity and mortality. Secondary outcomes were body mass index (BMI), percent excess weight loss (%EWL), and percent excess BMI lost (%EBMIL) at 1 year postoperatively.

RESULTS

A total of 1295 patients underwent a conversion from LAGB to LRYGB at our center: 1167 patients (90.1%) in one stage and 128 patients (9.9%) in two stages. There was no mortality. An early (30-day) postoperative complication occurred in 93 patients (7.2%), with no significant difference found between groups. Hemorrhage was the most common complication in 39 patients (3.0%), and the reoperation was required in 19 patients (1.4%). At 1 year postoperatively, the mean BMI was 28.0 kg/m2, the mean %EWL 72.8%, and the mean %EBMIL 87.0%. No statistically significant difference was found between the groups.

CONCLUSION

Conversion to LRYGB can be considered as a safe and effective option with low complication rate and good weight loss outcomes at 1 year. One-stage conversion provides the same early outcome as two-step surgery with a competent surgeon.

Medium Term Outcomes of Revision Laparoscopic Sleeve Gastrectomy after Gastric Banding: A Propensity Score Matched Study

PURPOSE

Revision bariatric surgery may be undertaken after weight loss failure and/or complications following primary bariatric surgery. This study aims to compare the efficacy and safety of revision laparoscopic sleeve gastrectomy (RLSG) after gastric banding (GB) to those of primary laparoscopic sleeve gastrectomy (PLSG).

MATERIALS AND METHODS

A retrospective, propensity-score matched study was conducted to compare between PLSG (control) patients and RLSG after GB (treatment) patients. Patients were matched using 2:1 nearest neighbor propensity score matching without replacement. Patients were compared on weight loss outcomes and postoperative complications for up to five years.

RESULTS

144 PLSG patients were compared against 72 RLSG patients. At 36 months, PLSG patients had significantly higher mean %TWL than RLSG patients (27.4 ± 8.6 [9.3-48.9]% vs. 17.9 ± 10.2 [1.7-36.3]%, p < 0.01). At 60 months, both groups had similar mean %TWL (16.6 ± 8.1 [4.6-31.3]% vs. 16.2 ± 6.0 [8.8-22.4)]%, p > 0.05). Early functional complication rates were slightly higher with PLSG (13.9% vs. 9.7%), but late functional complication rates were comparatively higher with RLSG (50.0% vs. 37.5%). The differences were not statistically significant (p > 0.05). Both early (0.7% vs 4.2%) and late (3.5% vs 8.3%) surgical complication rates were lower in PLSG patients compared to RLSG patients but did not reach statistical significance (p > 0.05).

CONCLUSION

RLSG after GB has poorer weight loss outcomes than PLSG in the short-term. Although RLSG may carry higher risks of functional complications, the safety of RLSG and PLSG are overall comparable.

Comparison of early post-operative complications in primary and revisional laparoscopic sleeve gastrectomy, gastric bypass, and duodenal switch MBSAQIP-reported cases from 2015 to 2019

BACKGROUND

Sleeve gastrectomy (SG) is now the most performed bariatric surgery, though gastric bypass (GB) and duodenal switch (DS) remain common, especially as conversion/revision (C/R) procedures. This analysis compared early postoperative outcomes of primary and C/R laparoscopic SG to DS and GB; and primary procedures of each vs C/R counterparts.

METHODS

The Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) dataset was queried for SG, GB, and DS cases from 2015 to 2019. Multivariable logistic regression calculated crude and adjusted odds ratios for surgical site infection (SSI), reoperation, and readmission at 30 days in two initial comparisons: (1) primary SG vs DS or GB and (2) C/R SG vs DS or GB. A secondary analysis compared primary GS, GB, or DS with C/R counterparts. Models were adjusted for confounding demographics and comorbidities.

RESULTS

Of 755,968 primary cases, most were SG (72.8%), followed by GB (26.3%), then DS (0.9%). Compared to SG, GB and DS demonstrated higher odds of SSI (aOR 3.02 [2.84, 3.2]), readmission (aOR 1.97 [1.92, 2.03]), and reoperation (aOR 2.74 [2.62, 2.86]), respectively. Of 68,716 C/R cases, SG was most common (43.2%), followed by GB (37.5%), then DS (19.2%). C/R GB and DS demonstrated greater risk of SSI (aOR 2.28 [1.98, 2.62]), readmission (aOR 2.10 [1.94, 2.27]), and reoperation (aOR 2.3 [2.04, 2.59]) vs SG, respectively. C/R SG and DS demonstrated greater risk of SSI (OR 2.09 [1.66, 2.63]; 1.63 [1.24, 2.14), readmission (OR 1.13 [1.02, 1.26]), and reoperation (OR 1.27 [1.06, 1.52]; 1.58 [1.24, 2.0]), vs primary procedures. C/R DS demonstrated greater risk of SSI (OR 1.23 [1.66, 2.63]).

CONCLUSIONS

Early complications are comparable between GB and DS, and greater than SG. In C/R procedures, GB and DS demonstrate greater risk than SG. Overall, C/R procedures demonstrate greater risk of most, but not all, early postoperative complications.

Propensity score matching analysis comparing outcomes between primary and revision Roux-en-Y gastric bypass after adjustable gastric banding: a retrospective record-based cohort study

BACKGROUND

One-stage revision Roux-en-Y gastric bypass (RRYGB) after Laparoscopic adjustable gastric banding (LAGB) is widely adopted, but its safety is still debated.

OBJECTIVE

This study aimed to compare outcomes between primary Roux-en-Y gastric bypass (PRYGB and RRYGB after LAGB.

METHOD

A retrospective record-based cohort study of patients who underwent PRYGB and RRYGB for failed LAGB and completed at least 2 years of follow-up from 2008 to 2019. Propensity score matching (PSM) analysis was conducted to obtain a balanced sample of patients with RRYGB and PRYGB interventions by adjusting for baseline covariates including age and sex.

RESULTS

Patients with PRYGB (n = 558) and RRYGB (n = 156) were included. PSM identified 98 patients for RRYGB and 98 patients for PRYGB. Both cohorts exhibited significant reductions in BMI compared to baseline values (p < 0.001), but reductions were significantly higher in PRYGB compared to those in RRGYB at 6 months (- 10.55 ± 8.54 vs. - 8.38 ± 5.07; p = 0.032), 1-year (- 21.50 ± 8.19 vs. 16.14 ± 6.93; p < 0.001), and 2 years (- 24.02 ± 7.85 vs. - 18.93 ± 6.80; p < 0.001), respectively. A significant improvement in food tolerance from the 1st to the 2nd year was seen after RYGB (p < 0.001). The rates of early and late complications were similar in both cohorts (p = 0.537, p = 1.00). Overall re-intervention rates were 5.1 and 3.1% for RRYGB and PRYGB p = 0.721). Both cohorts exhibited significant improvement in comorbidities after 2 years (p < 0.001).

CONCLUSIONS

One-stage RRYGB for failed LAGB is safe and effective with comparable rates of complications, re-interventions, and resolution of associated comorbid conditions compared to PRYGB.

Postoperative morbidity and weight loss after revisional bariatric surgery for primary failed restrictive procedure: A systematic review and network meta-analysis

BACKGROUND

revisional bariatric surgery is gaining increasing interest as long term follow-up studies demonstrate an elevated failure rate of primary surgery due to insufficient weight loss, weight regain or complications. This particularly concerns restrictive bariatric surgery which has been widely adopted from the '80s till present through different procedures, notably vertical banded gastroplasty, laparoscopic adjusted gastric banding and sleeve gastrectomy. The aim of this study is to define which revisional bariatric procedure performs the best after failure of primary restrictive surgery.

METHODS

a systematic review and network meta-analysis of 39 studies was conducted following the PRISMA guidelines and the Cochrane protocol.

RESULTS

biliopancreatic diversion with duodenal switch guarantees the best results in terms of weight loss (1 and 3-years %TWL MD: 12.38 and 28.42) followed by single-anastomosis duodenoileal bypass (9.24 and 19.13), one-anastomosis gastric bypass (7.16 and 13.1), and Roux-en-Y gastric bypass (4.68 and 7.3) compared to re-sleeve gastrectomy. Duodenal switch and Roux-en-Y gastric bypass are associated to an increased risk of late major morbidity (OR: 3.07 and 2.11 respectively) compared to re-sleeve gastrectomy while no significant difference was highlighted for the other procedures. Re-sleeve gastrectomy is the revisional intervention most frequently burdened by weight recidivism; compared to it, patients undergoing single-anastomosis duodenoileal bypass have the lowest risk of weight regain (OR: 0.07).

CONCLUSION

considering the analyzed outcomes altogether, single-anastomosis duodenoileal bypass and one-anastomosis gastric bypass are the most performing revisional procedures after failure of restrictive surgery due to satisfying short and mid-term weight loss and low early and late morbidity. Moreover, single-anastomosis duodenoileal bypass has low risk of weight recidivism.

Safety and effectiveness of 1-stage conversion of adjustable gastric band-to-sleeve gastrectomy: a single-institution case-control study

BACKGROUND

Patients are increasingly referred for conversion of laparoscopic adjustable gastric band (LAGB) to laparoscopic Roux-en-Y gastric bypass (LRYGB) or sleeve gastrectomy (SG). The safety of a 1- versus 2-stage approach to this revision is debated.

OBJECTIVES

We examined the safety and efficacy of 1-stage conversion of LAGB to SG at our institution.

SETTING

University hospital.

METHODS

An institutional database was used to retrospectively identify patients who underwent single-stage LAGB-to-SG conversion between 2010 and 2018. Patients were matched 1:1 for age, sex, and body mass index with primary SG patients during this same period. Primary endpoints were operative time, complication rate, length of hospital say, and weight loss 12 months from surgery.

RESULTS

Two-hundred and twenty-nine patients undergoing conversion of LAGB to SG were identified. Median postoperative length of hospital stay was 2 days. Two patients (.8%) developed surgical site infection. One patient (.4%) developed a postoperative myocardial infarction. There were 4 total readmissions (1.7%) and 1 reoperation within 30 days (.4%). There were no statistically significant differences in 30-day complication rates between groups. Weight loss at 12 months was significantly different: Median body mass index loss for conversion patients was 5.1 kg/m² compared with 8.85 kg/m² for patients in the primary SG group (P < .0001).

CONCLUSION

Single-stage conversion of LAGB to SG is safe and effective. Patients may not experience the same extent of weight loss as those with primary SG. Our findings represent the largest single-institutional experience to date and support a 1-stage approach whenever feasible.

Efficacy and safety of bariatric revisions in patients older than 65 years old

BACKGROUND

Bariatric surgery in advanced age patients (>65-years-old) has been proven safe and effective. Revisional bariatric surgery is infrequently required for cases of refractory obesity. However, there is a paucity of data regarding revisional surgery for the elderly. We hypothesize that revisional bariatric surgery is viable and safe in elderly patients.

METHODS

Retrospective chart review of all bariatric revisions performed at two high-volume bariatric centers of excellence between 2011 and 2018. Perioperative and long-term outcomes were compared between patients >65 and those <65-years-old.

RESULTS

145 bariatric revisions were performed for weight loss. 10% (N = 15) were >65 years old. There were no differences in mortality between the two groups There was a longer median length of stay in the younger cohort (2 vs 1 day, p = 0.001). Percent excess weight loss was similar at 12-months, as was resolution of comorbidities.

CONCLUSIONS

Bariatric revisions in elderly patients appears to be safe and effective. Revisional surgery in this population was not shown to have increased morbidity or mortality with similar excess body weight loss when compared to a younger cohort.

Conversion of Adjustable Gastric Banding to Stapling Bariatric Procedures: Single- or Two-stage Approach

OBJECTIVE

The aim of this study was to compare the safety of single- versus two-stage conversion of adjustable gastric band (AGB) to gastric bypass (RYGB) or sleeve gastrectomy (SG).

SUMMARY BACKGROUND DATA

AGB patients often present for conversion to RYGB or SG. The impact of single- or two-stage approach of such conversion remains unclear.

METHODS

A statewide database was used to identify all patients who underwent AGB removal and concurrent (single-stage) or interval (two-stage) RYGB or SG. Propensity score matching schemes were constructed to account for differences in baseline comorbidities and demographics, allowing for matched pairs available for comparisons.

RESULTS

A total of 4330 patients underwent AGB conversion. Complications, readmissions, and ED visits were noted in 394 (9.1%), 278 (6.42%), and 589 (13.6%) patients, respectively. Three hundred sixty-seven matched pairs underwent RYGB; single-stage patients experienced shorter length of stay (LOS) (median difference -1 d, P < 0.0001), less complications [risk difference (RD): -8.4%, 95% confidence interval (CI), -13.4% to -3.5%], readmissions (RD: -5.2%, 95% CI, -9.6% to -0.8%), and ED visits (RD: -5.7%, 95% CI, -11.3% to -0.2%). Eight hundred seventy-five matched pairs underwent SG; single-stage patients experienced improved outcomes in all measures examined. For single-stage procedures (809 pairs), RYGB was associated with longer LOS, and more complications (RD: 3.3%, 95% CI, 0.9%-5.8%), with similar readmissions, and ED visits.

CONCLUSIONS

AGB conversion procedures have low morbidity. Single-stage conversion is associated with lower morbidity compared with the two-stage approach. Conversion to SG seems to be safer than RYGB.

Weight Regain and Insufficient Weight Loss After Bariatric Surgery: Definitions, Prevalence, Mechanisms, Predictors, Prevention and Management Strategies, and Knowledge Gaps-a Scoping Review

Some patients experience weight regain (WR) or insufficient weight loss (IWL) after bariatric surgery (BS). We undertook a scoping review of WR and IWL after BS. We searched electronic databases for studies addressing the definitions, prevalence, mechanisms, clinical significance, preoperative predictors, and preventive and treatment approaches including behavioral, pharmacological, and surgical management strategies of WR and IWL. Many definitions exist for WR, less so for IWL, resulting in inconsistencies in the reported prevalence of these two conditions. Mechanisms and preoperative predictors contributing to WR are complex and multifactorial. A range of the current knowledge gaps are identified and questions that need to be addressed are outlined. Therefore, there is an urgent need to address these knowledge gaps for a better evidence base that would guide patient counseling, selection, and lead to improved outcomes.

Clinical Outcomes of Sleeve Gastrectomy Versus Roux-En-Y Gastric Bypass After Failed Adjustable Gastric Banding

BACKGROUND

Over recent decades, laparoscopic adjustable gastric banding (LAGB) has been among the most common bariatric surgeries. Nowadays, many patients require revision surgery due to insufficient weight loss and band-related complications. Sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) are the two most common revision surgeries for failed LAGB, but the conclusions about their efficacy and safety have been inconsistent. This meta-analysis aimed to review the clinical outcomes of SG and RYGB after failed LAGB.

METHODS

In accordance with the PRISMA guidelines, the PubMed, Embase, Scopus, and Cochrane Central Register of Controlled Trials (CENTRAL) databases were systematically searched for articles that had studied the efficacy and safety of SG and RYGB. The most appropriate effects model was chosen based on the heterogeneity of the articles included in this meta-analysis. Statistical analysis was conducted using Stata 14.0.

RESULTS

Of 586 articles that were retrieved, 16 articles which examined 2141 SG and 2990 RYGB patients met the inclusion criteria. The patients in RYGB groups showed increased percent excess weight loss (%EWL) at 12 and 24 months after revision surgery but no statistically significant change was found about %EWL after 3, 6, or 36 months. In addition, RYGB was associated with a higher rate of complications, interventions, and readmission in addition to being of more operative time.

CONCLUSIONS

This review suggested that RYGB was more effective at demonstrating weight loss after 12 and 24 months, but comparisons of the long-term efficacy of RYGB with that of SG remain inconclusive. In addition, RYGB was accompanied by a greater number of post-operative complications, interventions, and readmissions. Thus, surgeons should consider the overall status of the patients and their comorbidities as crucial factors when selecting a form of revision surgery. Additional high-quality randomized controlled studies are required to further compare the efficacy and safety of these treatments with longer follow-up times.

Efficiency of Laparoscopic One-Step Revision of Failed Adjusted Gastric Banding to Gastric Sleeve: a Retrospective Review of 101 Consecutive Patients

BACKGROUND

Until recently, laparoscopic adjustable gastric banding (LAGB) was one of the most commonly performed bariatric surgeries worldwide. Today, its high rate of complications and failure rates up to 70% requires revisional surgery. The one-stage conversion from LAGB to laparoscopic sleeve gastrectomy (LSG) has been shown to be safe, although there are some concerns on efficacy and long-term weight loss.

OBJECTIVES

To demonstrate that one-step revision of LAGB to another restrictive procedure, such as LSG, might have efficient long-term outcomes.

METHODS

The charts from 133 revisional LSGs for failed or complicated LAGB were retrospectively reviewed for the period between January 2010 and August 2017. Thirty-two patients were excluded for loss to follow-up. Demographics, complications, and percentage of excess weight loss (%EWL) were determined.

RESULTS

One hundred one patients were included (85 women and 16 men), with a mean age of 48.5 years, and a mean body mass index of 47.1 kg/m². During the follow-up, 15 patients (15%) underwent a second revisional surgery for weight loss failure (8 Roux-en-Y gastric bypass (RYGBP), 3 biliopancreatic diversion, 3 single anastomosis duodenal-ileal bypass, 1 revisional LSG). Ten patients (10%) had long-term complications (8 severe reflux and 2 stenosis) during this period and underwent a second revisional surgery (10 RYGBP). The remaining 76 had a mean follow-up of 4.3 years and a mean %EWL of 53.2%.

CONCLUSION

Single-stage conversion to LSG is a safe and appropriate solution for failed or complicated LAGB with good long-term weight loss.

Gastric band conversion to Roux-en-Y gastric bypass shows greater weight loss than conversion to sleeve gastrectomy: 5-year outcomes

BACKGROUND

Roux-en-Y gastric bypass (RYGB) and laparoscopic sleeve gastrectomy (LSG) are often used as revisional surgeries for a failed laparoscopic adjustable gastric band (LAGB). There is debate over which procedure provides better long-term weight loss.

OBJECTIVE

To compare the weight loss results of these 2 surgeries.

SETTING

University hospital, United States.

METHODS

A retrospective review was conducted of all LAGB to RYGB and LAGB to LSG surgeries performed at a single institution. Primary outcomes were change in body mass index (BMI), percent excess BMI lost, and percent weight loss. Secondary outcomes included 30-day complications and reoperations.

RESULTS

The cohort included 192 conversions from LAGB to RYGB and 283 LAGB to LSG. The baseline age and BMI were similar in the 2 groups. Statistical comparisons made between the 2 groups at 24 months postconversion were significant for BMI (RYGB = 32.93, LSG = 38.34, P = .0004), percent excess BMI lost (RYGB = 57.8%, LSG = 29.3%, P < .0001), and percent weight loss (RYGB = 23.4%, LSG = 12.6%, P < .0001). However, the conversion to RYGB group had a higher rate of reoperation (7.3% versus 1.4%, P = .0022), longer operating room time (RYGB = 120.1 min versus LSG = 115.5 min, P < .0001), and longer length of stay (RYGB = 3.33 d versus LSG = 2.11 d, P < .0001) than the LAGB to LSG group. Although not significant, the conversion to RYGB group had a higher rate of readmission (7.3% versus 3.5%, P = .087).

CONCLUSION

Weight loss is significantly greater for patients undergoing LAGB conversion to RYGB than LAGB to LSG. However, those undergoing LAGB conversion to RYGB had higher rates of reoperation and readmission. Patients looking for the most effective weight loss surgery after failed LAGB should be advised to have RYGB performed, while also understanding the increased risks of the procedure.

Roux-en-Y Gastric Bypass Versus Sleeve Gastrectomy as Revisional Procedures after Adjustable Gastric Band: 5-Year Outcomes

INTRODUCTION

In 2013, a worldwide bariatric surgery survey showed that laparoscopic adjustable gastric banding (LAGB) has been abandoned in favor of laparoscopic sleeve gastrectomy (LSG) and laparoscopic Roux-en-y gastric bypass (LRYGBP).

PURPOSE

The aim of this study was to compare results of LRYGBP and LSG performed as a revisional procedure after LAGB.

MATERIALS AND METHODS

All patients converted from LAGB to LSG or to LRYGBP from January 2007 to December 2011 were included in the study. Clinical data collected were age, gender, indications for revision, complications, body mass index (BMI), and body weight at revisional procedures. Weight loss was calculated at 1, 3, and 5 years after conversion.

RESULTS

Fifty-one patients were included in this study, 43 females and 8 males. Twenty-four patients were converted to LRYGBP (LRYGBP group) and 27 to LSG (LSG group). Indication for conversion was weight loss failure in 34 (67%) patients and band complications in 17 (33%) patients. No significant difference in age, BMI, and body weight in the two groups was found at the time of revision. One patient converted to LRYGBP had an internal hernia; one patient initially scheduled for LSG was intraoperatively converted to LRYGBP due to staple line leak. No other major perioperative complication was observed. Follow-up rate at 5 years was 84.3% (43 patients out of 51 patients) Delta-BMI and percentage of excess weight loss (%EWL) were not significantly different in the two groups at 1, 3, and 5 years (p > 0.05).

CONCLUSION

LRYGBP or LSG are feasible and effective surgical options after LAGB. Satisfactory weight loss was achieved after both procedures.

No effect of different bariatric surgery procedures on LINE-1 DNA methylation in diabetic and nondiabetic morbidly obese patients

BACKGROUND

Bariatric surgery (BS) is proposed as a highly effective therapy for reducing weight and improving obesity-related co-morbidities. The molecular mechanisms involved in the metabolic improvement after BS are not completely resolved. Epigenetic modifications could have an important role.

OBJECTIVE

The aim of this study was to evaluate the effect of different BS procedures (Roux-en-Y gastric bypass and laparoscopic sleeve gastrectomy) on global DNA methylation (long interspersed nucleotide element 1 [LINE-1]) in a group of nondiabetic and diabetic severely obese patients.

SETTING

University hospital, Spain.

METHODS

This study included 60 patients (30 nondiabetic and 30 diabetic severely obese patients) undergoing BS: 31 patients underwent Roux-en-Y gastric bypass and 29 underwent laparoscopic sleeve gastrectomy. Before and 6 months post-BS, anthropometric data, blood pressure, and metabolic parameters were determined. LINE-1 DNA methylation was quantified by pyrosequencing. We used the methylation levels of tumor necrosis factor-α as a control gene promoter.

RESULTS

There were no differences between LINE-1 methylation levels at baseline and at 6 months after surgery (66.3±1.6 versus 66.2±2.06). Likewise, there was no statistically significant difference on LINE-1 methylation levels when we stratified according to metabolic status (diabetic versus nondiabetic), nor was there regarding the BS procedure. A strong correlation was shown between LINE-1 methylation levels and weight at baseline both in diabetic and nondiabetic obese patients (r = .486; P<.001). Tumor necrosis factor-α methylation levels increased significantly after BS in the group of diabetic obese patients.

CONCLUSION

After BS, global LINE-1 methylation is not modified in the short term. More studies are required to determine if LINE-1 is a stable epigenetic marker, or, on the contrary, if it is susceptible to modification by external factors such as changes in lifestyle or a surgical intervention.