Prevalence of low skeletal muscle mass following bariatric surgery

BACKGROUND AND AIMS

Evidence on the occurrence of low skeletal muscle mass (low-SMM) following bariatric surgery (BS) as well as on the impact of low-SMM antedating BS on post-surgical body composition (BC) are scant. In this context, we aimed to prospectively evaluate the prevalence of low-SMM prior to and up to 5 years after BS, and to evaluate pre-surgical low-SMM as an independent risk factor for the presence of low-SMM after BS.

METHODS

Retrospective analysis of prospectively collected database. BC was assessed by bioelectrical impedance analysis (BIA). A BIA-based formula was used to calculate skeletal muscle mass (SMM). Class I and class II low-SMM were defined respectively as a SMM index (SMMI = SMM/height²) value between -1 and -2, or > -2 standard deviations from the gender-specific regression line of the BMI versus the SMMI relationship in our reference group.

RESULTS

A total 952 subjects were included, with BC being available for 877 (92%) subjects at 12 months and for 576 subjects (60%) at 60 months after BS. Prior to surgery, and at 12-, or at 60-months after surgery, class I and class II low-SMM was ascertained respectively in 15.6% and 4.6%, 5.3% and 1.4%, and 16.6% and 6.3% of the study participants. Logistic regression analysis showed that the occurrence of low-SMM at 12- and 60-months follow-up, was independently predicted not only by age at the time of surgery [respectively, HR: 1.052 (95% CI 1.020-1.084), p = 0.001; and 1.042 (95% CI 1.019-1.066); p < 0.001] but also by the presence of low-SMM prior to surgery [respectively, HR: 10.717 (95% CI 5.771-19.904), p < 0.001; and 5.718 (95% CI 3.572-9.153); p < 0.001].

CONCLUSIONS

Our data suggest that a low-SMM phenotype occurs not only in obesity surgery candidates but also after BS, and that low-SMM prior to surgery is an important risk factor for low-SMM throughout post-surgical follow-up.

Fat-Free Mass and Skeletal Muscle Mass Gain Are Associated with Diabetes Remission after Laparoscopic Sleeve Gastrectomy in Males but Not in Females

Besides massive body weight loss, laparoscopic sleeve gastrectomy (LSG) causes massive lean mass, including fat-free mass (FFM) and skeletal muscle mass (SM) that present higher metabolic rates in males. This study examines sex differences in FFM and SM changes of type 2 diabetes (T2D) remission at 12 months post-LSG. This cohort study recruited 119 patients (53.7% females) with T2D and obesity (body mass index 42.2 ± 7.0 kg/m²) who underwent LSG. Fat-mass (FM) loss was higher in males than in females (−12.8 ± 6.2% vs. −9.9 ± 5.0%, p = 0.02) after one-year post-operation. Regardless of the weight-loss difference, males had higher FFM and SM gain than did females (12.8 ± 8.0 vs. 9.9 ± 5.0% p = 0.02 and 6.5 ± 4.3% vs. 4.9 ± 6.2%, p = 0.03, respectively). Positive correlations of triglyceride reduction with FM loss (r = 0.47, p = 0.01) and SM gain (r = 0.44, p = 0.02) over 12 months post-operation were observed in males who achieved T2D remission. The T2D remission rate significantly increased 16% and 26% for each additional percentage of FFM and SM gain one year after LSG, which only happened in males. Increased FFM and SM were remarkably associated with T2D remission in males, but evidence lacks for females.

How Does Fat Mass Change in the First Year After Bariatric Surgery? A Systemic Review and Meta-Analysis

This systematic review and meta-analysis investigated the time-course effect of different type of bariatric surgeries (BS) up to 1 year post-surgery on fat mass (FM) and body fat percentage (BFP) in patients with morbid obesity. We searched PubMed, Scopus, EMBASE, ISI web of science, and Cochrane databases from October 2002 until May 2020 with no restriction in the English language, to find studies examining the effect of BS on FM (kg) and BFP (%) in morbid obese patients. Meta-analysis of 103 studies carried out on data of 18,166 and 14,575 morbid obese patients following BS, showed that BS was associated with a substantial decrease in FM and BFP, respectively, in 1 month (- 8.17 kg [95% CI - 9.07, - 7.27] and - 1.51% [95% CI - 2.56, - 0.46]), 3 months (- 15.75 [95% CI - 17.49, - 14.0] and - 4.90 [95% CI - 5.97, - 3.83]), 6 months (- 22.51 [95% CI - 23.93, - 21.09] and - 8.56% [95% CI - 9.63, - 7.49]), and 12 months (- 29.69 [95% CI - 31.3, - 28.09] and - 13.49% [95% CI - 14.52, - 12.40]) after the surgery. In conclusion, BS was associated with sustained declines in FM and BFP, from 1 to 12 months, with no indication of plateau phase post-surgery post-operatively. The present study emphasizes that post-bariatric care should have more focus on FM loss during 1-year post-surgery to identify the patients at risk for fat loss plateau.

Changes in serum albumin and liver enzymes following three different types of bariatric surgery: six-month follow-up. A retrospective cohort study

BACKGROUND

Few reports have examined the effects of Roux-en-Y gastric bypass (RYGB), one-anastomosis gastric bypass (OAGB) and sleeve gastrectomy (SG) on changes to serum albumin (Alb) and liver enzyme levels.

OBJECTIVE

To compare short-term post-surgery changes in serum Alb, aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALKP) levels. Body composition changes were also measured and compared among three groups.

DESIGN AND SETTING

Retrospective cohort study conducted in Tehran, Iran.

METHODS

151 OAGB, RYGB and SG patients referred to the obesity clinic of Hazrat-e Rasool General Hospital, Tehran, Iran, were evaluated. Physical characteristics and biochemical parameters were measured pre-surgery and then after three and six months.

RESULTS

Through repeated measurements to determine intragroup changes, significant changes in serum AST (P = 0.003) and ALT (P < 0.001) were observed in follow-ups. However, Alb levels did not change (P = 0.413). Body fat, fat-free mass and muscle mass decreased significantly in each group (P < 0.05). In a univariate general linear model for determining intergroup changes, SG showed greater decreases in ALT and AST at three and six months (P < 0.05) and in ALKP at six months (P = 0.037), compared with OAGB. There were no significant differences in Alb levels. Also, RYGB had a greater effect on reducing fat percentage (three months, P = 0.011; six months, P = 0.059) and fat mass (three months, P = 0.042) than OAGB.

CONCLUSION

SG and RYGB may be superior to OAGB in reducing liver enzymes and body fat, respectively. However, Alb levels showed no significant differences.

Changes in fat-free mass and muscle mass at 6 and 12 months after biliopancreatic diversion with duodenal switch surgery

BACKGROUND

Bariatric surgery is associated with concomitant loss in both fat and muscle masses. Literature on muscle composition/quality after bariatric surgery is limited.

OBJECTIVES

To measure and compare the changes in fat-free mass with the changes in muscle composition after biliopancreatic diversion with duodenal switch surgery (BPD/DS).

SETTING

Bariatric surgery is associated with concomitant loss in both fat and muscle masses. Literature on muscle composition/quality after bariatric surgery is limited.

METHODS

Forty patients underwent BPD/DS and 22 patients are considered as controls. Bioelectrical impedance analysis (body composition) and computed tomography scan at the midthigh and abdominal levels (muscle composition) were performed at baseline, 6, and 12 months.

RESULTS

At 6 and 12 months, the BPD/DS group displayed significant reduction in weight (12 months: -46.6 ± 13.5 kg) and fat-free mass (12 months: -8.2 ± 4.4 kg; both P < .001). A significant reduction in abdominal (-15 ± 8%, P < .001) and midthigh muscle areas (-18 ± 7%, P < .001) was observed during the first postoperative 6 months, followed by a plateau after 6 months (abdominal: -1 ± 5%, midthigh: -1 ± 4%, both P > .05). At 6 months, both midthigh fat-infiltrated muscle (-22 ± 10%, P < .001) and normal-density muscle (-16 ± 9%, P < .001) areas decreased. Further reduction at 12 months was only observed in the fat-infiltrated muscle (-11 ± 8%, P < .001) in comparison with an increase in the normal-density muscle area (5 ± 8%, P = .001). There was no significant change for the control group.

CONCLUSIONS

Reduction in muscle, assessed with computed tomography scans, occurs mostly during the first 6 months postoperatively after BPD/DS. Focus on muscle quantity as well as quality, using precise imaging methods, instead of quantifying total body lean mass, is likely to provide better assessment in body content modulation after BPD/DS.

Prospective Longitudinal Trends in Body Composition and Clinical Outcomes 3 Years Following Sleeve Gastrectomy

BACKGROUND AND AIMS

Longitudinal assessment of body composition following bariatric surgery allows monitoring of health status. Our aim was to elucidate trends of anthropometric and clinical outcomes 3 years following sleeve gastrectomy (SG).

METHODS

A prospective cohort study of 60 patients who underwent SG. Anthropometrics including body composition analysis measured by multi-frequency bioelectrical impedance analysis, blood tests, liver fat content measured by abdominal ultrasound and habitual physical activity were evaluated at baseline and at 6 (M6), 12 (M12), and 36 (M36) months post-surgery.

RESULTS

Sixty patients (55% women, age 44.7 ± 8.7 years) who completed the entire follow-up were included. Fat mass (FM) was reduced significantly 1 year post-surgery (55.8 ± 11.3 to 26.7 ± 8.3 kg; P < 0.001) and then increased between 1 and 3 years post-operatively, but remained below baseline level (26.7 ± 8.3 to 33.1 ± 11.1 kg; P < 0.001). Fat free mass (FFM) decreased significantly during the first 6 months (64.7 ± 14.3 to 56.9 ± 11.8 kg; P < 0.001), slightly decreased between M6 and M12 and then reached a plateau through M36. Weight loss "failure" (< 50% excess weight loss) was noticed in 5.0% and 28.3% of patients at M12 and M36, respectively. Markers of lipid and glucose metabolism changed thereafter in parallel to the changes observed in FM, with the exception of HDL-C, which increased continuingly from M6 throughout the whole period analyzed (45.0 ± 10.2 to 59.5 ± 15.4 mg/dl; P < 0.001) and HbA1c which continued to decrease between M12 and M36 (5.5 ± 0.4 to 5.3 ± 0.4%; P < 0.001). There were marked within-person variations in trends of anthropometric and clinical parameters during the 3-year follow-up.

CONCLUSIONS

Weight regain primarily attributed to FM with no further decrease in FFM occurs between 1 and 3 years post-SG. FM increase at mid-term may underlie the recurrence of metabolic risk factors and can govern clinical interventions.

Evolution of body composition of obese patients undergoing bariatric surgery

BACKGROUND & AIMS

Bariatric surgery is increasingly common in the fight against morbid obesity. However, after this intervention, it is not fully understood the evolution of weight loss and how body composition changes. The objective of this work is to study the evolution after surgery of weight and body composition of obese patients that underwent bariatric surgery.

METHODS

In this retrospective and prospective study, we studied initially BMI and body composition of obese patients who attended nutritional appointments at Centro Hospitalar São João E.P.E. We collected personal data and anthropometric measurements between the pre-surgery appointment up to 60 months after surgery.

RESULTS

The sample consisted of 793 patients, of which 86.5% were female and 13.5% were male, with a mean age of 43 years (SD = 10.5 years) and mean height of 1.62 m (SD = 0.079 m). Patients undergoing gastric band, sleeve gastrectomy and gastric bypass had, respectively, an initial BMI reduction of 6.3 kg/m², 13.2 kg/m² and 15.4 kg/m² and an initial fat mass% reduction of 4.4%, 14.3% and 17.3%. On the other hand, they had an initial increase of 3.2%, 10.8% and 12.4% of water%, 1.4%, 3.9% and 4.6% of fat and water-free mass%, and 1.9%, 7.3% and 8.9% of skeletal muscle mass%, respectively. BMI and fat mass% on average had a large decrease in the first 12 months, increasing slightly from 24 months onwards. The opposite behaviour was observed for water%, fat and water-free mass% and skeletal muscle mass%.

CONCLUSIONS

Bariatric surgery initially allows a substantial decrease in BMI as well as beneficial changes in the overall body composition of the individuals. Gastric bypass was the method that caused the most changes, followed by sleeve gastrectomy and, finally, gastric band. On average, after 24 months of follow-up, and for all surgical procedures studied, we observed a reversion in BMI and body composition values, showing the difficulties in maintaining weight and fat loss.

Fat-Free Mass and Skeletal Muscle Mass Five Years After Bariatric Surgery

OBJECTIVE

This study investigated changes in fat-free mass (FFM) and skeletal muscle 5 years after surgery in participants from the Longitudinal Assessment of Bariatric Surgery-2 trial.

METHODS

A three-compartment model assessed FFM, and whole-body magnetic resonance imaging (MRI) quantified skeletal muscle mass prior to surgery (T0) and 1 year (T1), 2 years (T2), and 5 years (T5) postoperatively in 93 patients (85% female; 68% Caucasian; age 44.2 ± 11.6 years) who underwent gastric bypass (RYGB), sleeve gastrectomy, or adjustable gastric band. Repeated-measures mixed models were used to analyze the data.

RESULTS

Significant weight loss occurred across all surgical groups in females from T0 to T1. FFM loss from T0 to T1 was greater after RYGB (mean ± SE: -6.9 ± 0.6 kg) than adjustable gastric band (-3.5 ± 1.4 kg; P < 0.05). Females with RYGB continued to lose FFM (-3.3 ± 0.7 kg; P < 0.001) from T1 to T5. A subset of males and females with RYGB and MRI-measured skeletal muscle showed similar initial FFM loss while maintaining FFM and skeletal muscle from T1 to T5.

CONCLUSIONS

Between 1 and 5 years following common bariatric procedures, FFM and skeletal muscle are maintained or decrease minimally. The changes observed in FFM and muscle during the follow-up phase may be consistent with aging.

A Comparative Study Examining the Impact of a Protein-Enriched Vs Normal Protein Postoperative Diet on Body Composition and Resting Metabolic Rate in Obese Patients after Sleeve Gastrectomy

BACKGROUND

We recently showed that an 8-week preoperative protein-enriched diet (PED) is associated with significant reductions in body weight and fat mass (FM) without significant loss of fat-free mass (FFM) in morbidly obese patients scheduled for laparoscopic sleeve gastrectomy (LSG).

OBJECTIVES

The objective of this study is to evaluate the impact of PED vs a normal protein diet (NPD) on total weight loss (TWL), FM, FFM, and resting metabolic rate (RMR) in patients after LSG.

METHODS

Before LSG and at 3, 6, and 12 months after, we prospectively measured and compared total body weight (TBW), FM, FFM, and RMR in 60 male patients who received either a NPD (n = 30) with protein intake 1.0 g/kg of ideal body weight, or a PED (n = 30) with protein intake 2.0 g/kg of ideal body weight. Compliance in following the prescribed diet was determined with food frequency questionnaires in all patients. The impact of NPD and PED on renal function was also evaluated.

RESULTS

Despite non-significant variation in total body weight (TBW), FM decreased more significantly (p < 0.01) with the PED compared to the NPD. In addition, the PED group showed a significantly (p < 0.01) lower decrease in FFM and RMR when compared with the NPD group. Both groups showed high compliance in following the prescribed diets, without negative impact on renal function.

CONCLUSION

PED is more effective than NPD in determining FM loss and is associated with a lower decrease in FFM and RMR, without interfering with renal function in male patients after LSG.

Fat mass, fat-free mass, and resting metabolic rate in weight-stable sleeve gastrectomy patients compared with weight-stable nonoperated patients

BACKGROUND

There is evidence that body composition and resting metabolic rate (RMR) in weight-stable patients after Roux-en-Y gastric bypass and duodenal switch is similar to that of nonoperated individuals within the same body mass index (BMI) interval. Currently, data concerning fat mass (FM), fat-free mass (FFM), and RMR on weight-stable patients after sleeve gastrectomy (SG) are lacking.

OBJECTIVES

To assess FM, FFM, and RMR, in a selected and homogenous population of weight-stable SG patients (WSSG) and compare them with those obtained from healthy normal weight-stable nonoperated (WSNO) volunteers controls of similar sex, age, and BMI.

SETTING

University hospital, Italy.

METHODS

We assessed total weight, FM, and FFM by bioelectrical impedance assay, and RMR by indirect calorimetry, in 70 WSSG patients (47 females, 23 males) at a mean follow-up of 3.2 ± 2.1 years after SG and compared them with 70 healthy WSNO volunteers, as controls (47 females, 23 males).

RESULTS

There was no significant difference between WSSG and WSNO groups concerning total weight (males, 72 ± 2.66 versus 72.8 ± 1.99 kg, P = .0254; females 65.1 ± 2.53 versus 63.7 ± 2.87 kg, P = .0139), FM (males, 17.7 ± 1.53 versus 16.7 ± 1.57 kg, P = .0341; females 19.6 ± 0.50 versus 18.5 ± 2.85 kg, P = .0104), FFM (males, 54.3 ± 3.07 versus 56.1 ± 3.30 kg; P = .049; females 45.5 ± 2.29 versus 45.1 ± 1.13 kg, P = .287), and RMR (males, 1541 ± 121.3 versus 1463 ± 74.4 kcal/d; P = .0118; females 1214 ± 54.9 versus 1250 ± 90.1 kcal/d, P = .0215).

CONCLUSION

At a mean follow-up of 3.2 ± 2.1 years after SG, WSSG patients of both sexes have a FM, FFM, and RMR comparable to that of healthy WSNO individuals within the same age and BMI interval. These findings further support bariatric surgery-induced weight loss as a physiologic process and indicate that young patients, in the setting of an adequate preoperative and postoperative specific diet and moderate physical activity, do not suffer from excessive FFM depletion after SG in the mid-term.

The SURMetaGIT study: Design and rationale for a prospective pan-omics examination of the gastrointestinal response to Roux-en-Y gastric bypass surgery

Objective

To describe the protocol of the SURgically induced Metabolic effects on the Human GastroIntestinal Tract (SURMetaGIT) study, a clinical pan-omics study exploring the gastrointestinal tract as a central organ driving remission of type 2 diabetes mellitus (T2DM) after Roux-en-Y gastric bypass (RYGB). The main points considered in the study’s design and challenges faced in its application are detailed.

Methods

This observational, longitudinal, prospective study involved collection of gastrointestinal biopsy specimens, faeces, urine, and blood from 25 obese women with T2DM who were candidates for RYGB (20 patients for omics assessment and 5 for omics validation). These collections were performed preoperatively and 3 and 24 months postoperatively. Gastrointestinal transcriptomics; faecal metagenomics and metabolomics; plasma proteomics, lipidomics, and metabolomics; and biochemical, nutritional, and metabolic data were assessed to identify their short- and long-term correlations with T2DM remission.

Results

Data were collected from 20 patients before and 3 months after RYGB. These patients have nearly completed the 2-year follow-up assessments. The five additional patients are currently being selected for omics data validation.

Conclusion

The multi-integrated pan-omics approach of the SURMetaGIT study enables integrated analysis of data that will contribute to the understanding of molecular mechanisms involved in T2DM remission after RYGB.