Hypothyroidism and levothyroxine therapy following bariatric surgery: a systematic review,meta-analysis,network meta-analysis,and meta-regression

BackgroundMany health benefits of bariatric surgery are known and well-studied, but there is scarce data on the benefits of bariatric surgery on the thyroid function.ObjectiveWe aimed to make a meta-analysis regarding the impact of bariatric surgery on thyroid-stimulating hormone (TSH) levels, levothyroxine dose, and the status of subclinical hypothyroidism.SettingSystematic review and meta-analysis.MethodsPubMed, EMBASE, and Cochrane Library were searched up to December 2020 for relevant clinical studies. Random-effects model was used to pool results. Network meta-analysis was performed, incorporating direct and indirect comparisons among different types of bariatric surgery. Meta-regression analysis was performed to evaluate the impact of moderator variables on TSH levels and required levothyroxine dose after surgery. We followed the PRISMA guidelines for data selection and extraction. PROSPERO registry number: CRD42018105739.ResultsA total of 28 studies involving 1284 patients were included. There was a statistically significant decrease in TSH levels after bariatric surgery (mean difference = ?1.66 mU/L, 95%CI [?2.29, ?1.03], P < .0001). In meta-regression analysis, we found that the following moderator variables: length of follow-up, mean age, baseline TSH, and preoperative thyroid function, could explain 1%, 43%, 68%, and 88% of the between-study variance, respectively. Furthermore, subclinical hypothyroidism was completely resolved in 87% of patients following bariatric surgery. In addition, there was a statistically significant decrease of levothyroxine dose in frank hypothyroid patients following bariatric surgery (mean difference = ?13.20 mcg/d, 95%CI [?19.69, ?6.71]). In network meta-analysis, we found that discontinuing or decreasing levothyroxine dose was significant following Roux-en-Y gastric bypass, 1 anastomosis gastric bypass, and sleeve gastrectomy, (OR = 31.02, 95%CI [10.34, 93.08]), (OR = 41.73, 95%CI [2.04, 854.69]), (OR = 104.03, 95%CI [35.79, 302.38]), respectively.ConclusionsBased on our meta-analysis, bariatric surgery is associated with the resolution of subclinical hypothyroidism, a decrease in TSH levels, and a decrease in levothyroxine dose.     

Older age does not limit postbariatric surgery cognitive benefits: a preliminary investigation

BackgroundBariatric surgery is associated with cognitive benefits, but the nature of such gains may be variable across demographically and clinically diverse persons. Older adults achieve less weight loss and resolution of fewer medical co-morbidities after surgery compared to younger patients and are also at heightened risk for nutritional deficiencies. However, no study has examined the influence of age on cognitive improvements after bariatric surgery. The objective of this study was to determine the effects of age on cognitive function postbariatric surgery.MethodsA total of 95 participants enrolled in the Longitudinal Assessment for Bariatric Surgery completed a computerized cognitive test battery before bariatric surgery and at 12-weeks and 12-months postoperatively.ResultsBaseline cognitive impairments were common. Significant improvements were found in attention/executive function and memory abilities 12-weeks and 12-months after surgery. Age was not associated with baseline cognitive test performance. Separate multivariable regression analyses controlling for baseline attention/executive function and memory also showed that age was not a significant predictor of 12-week or 12-month performances in these domains (P>.05 for all).ConclusionThe present study provides preliminary evidence suggesting that older age does not preclude postbariatric surgery cognitive benefits. Prospective studies in more age diverse samples (i.e., up to 70 yr) are needed to determine whether bariatric surgery can reduce risk of age-related neurologic conditions like Alzheimer’s disease and stroke.     

Severe obesity and vitamin D deficiency treatment options before bariatric surgery: a randomized clinical trial

BackgroundObesity, which has various complications and co-morbidities, is an epidemic issue worldwide. Vitamin D deficiency (VDD) is a well-known metabolic disorder among patients with severe obesity. While they are good candidates for bariatric surgery, this deficiency can affect the outcome of surgery negatively.ObjectivesThe aim of this study was to compare 3 different VDD treatment strategies for use before bariatric surgery and compare serum vitamin D levels after 7 weeks.SettingsUniversity hospital, Isfahan, Iran.MethodsThis was a single-blinded, randomized clinical trial on 100 patients who were referred for bariatric surgery from 2016 to 2018. Vitamin D (VitD) level was checked before surgery for the patients included in the study, if their VitD level was <30 ng/mL. We rechecked their serum VitD in the 8^th week, after 7 weeks of treatment. The participants were randomly allocated into 3 groups: 33 patients were treated with 50,000 units VitD₃ capsules every week for 7 weeks; 33 patients were treated with a single dose of 300,000 units VitD₃ ampoule; and 34 patients were treated with a combination of a half of the injection dose, followed by the oral capsule for 4 weeks.ResultsNo case was lost during the follow-up time. No significant differences were found among the 3 groups in terms of their age (P = .654), body mass index (P = .434), sex (P = .799), initial 25(OH) VitD level (P = .273), and history of supplement use (P = .45). Mean serum VitD levels were 15.21, 13.16, and 13.37 ng/mL, respectively, before the surgery and reached 32.91, 24.74, and 29.49 ng/mL after 7 weeks of treatment in oral, injection, and combined groups, respectively. Finally, the 7-week oral treatment option had significantly higher levels of VitD (P value = .034).ConclusionVDD treatment with 50,000 units VitD₃ capsule every week for 7 weeks before bariatric surgery yields a higher level of VitD. Based on our findings, injectable supplements are not recommended for VDD treatment.     

Anemia and iron deficiency before and after bariatric surgery

BackgroundIron deficiency and anemia are changes often associated with obesity. Bariatric surgery is responsible for increasing the iron loss and reducing its absorption. The objective of this study was to evaluate anemia and iron deficiency before and after bariatric surgery and to relate them to possible predisposing factors.MethodsA retrospective study was conducted on obese patients submitted to open Roux-en-Y gastric bypass, in which clinical and laboratory data were obtained up to 48 months postoperatively. Patients were divided into groups according to the presence or absence of anemia and to the presence or absence of iron deficiency (even without anemia), and all data were compared between these groups.ResultsPreoperatively, 21.5% of patients had anemia and 20% had iron deficiency. The number of patients with anemia did not vary through the 4 years of the study, but ferritin levels significantly decreased with time (P<.01). Younger patients and patients with greater weight loss had a higher incidence of anemia. Female gender was a variable associated with a greater incidence of iron deficiency.ConclusionsAnemia and iron deficiency are frequent in obese patients and must be treated before surgery. Medical and nutritional surveillance is important in the postoperative period of bariatric surgery. Management of each condition must be directed at correcting the 2 major sources of iron deficiency and anemia: food intolerance (mostly meat intolerance) and losses (frequently due to menstruation). These are the factors more related to iron deficient anemia.     

Nutrition for pregnancy after metabolic and bariatric surgery: literature review and practical guide

When pregnancy follows metabolic and bariatric surgery (MBS), there are many important considerations related to nutritional status that may impact maternal and infant outcomes. Although evidence-based nutrition guidelines for pregnancy exist for the general population, there are limited practical recommendations that specifically address pregnancy after MBS. A literature search was conducted to investigate outcomes of women with a history of MBS and pregnancy. Search criteria focused on women 18 years of age and older who became pregnant after MBS. Search terms included “laparoscopic sleeve gastrectomy,” “Roux-en-Y gastric bypass,” “laparoscopic adjustable gastric banding,” “biliopancreatic duodenal switch,” and gestation terminology, and they were paired with the nutrition outcomes of interest. A total of 167 publications were identified; 46 articles were included in the final review. Data relating to gestation and fetal weight and nutrition and cardiometabolic data were extracted from the studies. Based on this review, women of childbearing age with a history of MBS should be evaluated and monitored for nutritional status before conception, during pregnancy, and postpartum.     

减重代谢手术对心脑血管不良事件的影响

肥胖是诱发心脑血管不良事件的重要原因之一,减重代谢手术是近年来新兴的被证实可安全、有效减轻患者体重,并改善肥胖相关合并症如2型糖尿病、高血压、代谢综合征等的一种方式。有研究发现减重代谢手术可改善心脑血管不良事件危险因素,如炎症、高血压、血脂异常等,但减重代谢手术可否显著降低肥胖患者心脑血管不良事件尚不明确。本文通过回顾相关文献报道,了解减重代谢手术对肥胖患者心脑血管不良事件的影响,进一步阐明减重代谢手术的疗效及应用价值。     

Relationship between bariatric surgery and periodontal status: a systematic review and meta-analysis

Background

The effects of bariatric surgery can reflect in the oral cavity and can cause alterations in oral health. This high prevalence of oral alterations in the pre and post-operative periods has been highlighted in different studies.

The effects of bariatric surgery on cognition in patients with obesity: a systematic review and meta-analysis

Obesity impairs cognition. Bariatric surgery can result in substantial weight loss in patients with severe obesity; however, the impact of bariatric surgery on cognitive function remains controversial. To quantify the effect of bariatric surgery on cognition in patients with severe obesity, we performed a meta-analysis of 20 studies retrieved from PubMed, Cochrane, and Embase. Of these, 6 cohort studies found that Roux-en-Y gastric bypass leads to better performance for immediate verbal memory function (standardized mean difference [SMD] = .56; 95% confidence interval [CI]: .30–.82, P < .0001; I2 = 0%) and delayed memory function (SMD = .64; 95% CI: .38–.90, P < .00001; I² = 0%) during in the short term. Similarly, positive impacts on immediate verbal memory function (SMD = .46; 95% CI: .09–.83, P < .00001) and delayed memory function (SMD = .84; 95% CI: .46–1.22, P < .0001) were identified during a long-term follow-up. The Roux-en-Y gastric bypass group showed no improvements in attention, cognitive speed, and executive function compared with the control obese group. In 14 longitudinal studies (12 single-arm pre-post comparison studies and 2 cohort studies whose control group had no follow-up cognitive data), patients performed better postoperatively than preoperatively in all cognitive domains during repeated assessments. The analysis for the 20 operative groups showed that individuals treated with bariatric surgery had higher scores after repeated assessment of most neuropsychological tests except for animal fluency and letter fluency than baseline scores. These findings suggest that patients with severe obesity may obtain immediate verbal and delayed memory function benefits from Roux-en-Y gastric bypass.     

Nutrient deficiencies in patients with obesity considering bariatric surgery: A cross-sectional study

BackgroundNutritional deficiencies are common after bariatric surgery, but few studies have examined them preoperatively. The objective of this study was to evaluate several vitamins, nutrients, and nutritional markers and their determinants in patients with obesity considering bariatric surgery.MethodsPreoperative values of fasting plasma glucose, insulin, lipid profile, 25-hydroxyvitamin D (25(OH)D), parathyroid hormone, thyroid-stimulating hormone, calcium, phosphate, albumin, magnesium, total proteins, liver function tests, iron, ferritin, folate, vitamin A, vitamin B12, selenium, and zinc were evaluated in 267 Caucasian outpatients (74.2% women, aged 40.5±12.6 years) who were considering bariatric surgery. The determinants of nutrient variability were analyzed by linear regression for nutrients with a prevalence of deficiency>10%, i.e., serum 25(OH)D, iron, phosphate, magnesium, and vitamin A.ResultsPrevalence of inadequate concentrations was high for 25(OH)D (67.9% with values≤20 ng/mL), magnesium (35.4%), phosphate (21.6%), iron (18.8%), and vitamin A (16.9%). Multiple deficiencies were common; 28.5%, 12.1%, and 6.3% of patients had 2, 3, and 4 deficiencies, respectively. In multivariate analyses, metabolic characteristics had an important impact on deficiencies, with lower values of 25(OH)D and vitamin A with increasing body mass index, lower values of 25(OH)D and magnesium with increasing fasting plasma glucose, and a positive correlation between vitamin A and triglycerides. Elevated TSH was associated with low iron concentrations.ConclusionAt all ages, micronutrient deficiencies were common, with high prevalence of concentration inadequacies for 25(OH)D, magnesium, phosphate, iron, and vitamin A. High body mass index and high fasting plasma glucose increased the risk of deficiencies, particularly for 25(OH)D. Preoperative screening and correction of deficiencies should be advised.     

Options in bariatric surgery: modeled decision analysis supports Roux-en-Y gastric bypass and sleeve gastrectomy as the treatments of choice

Background

Obesity is a chronic disease associated with significant morbidity and mortality. Bariatric surgery has been shown to significantly reduce both morbidity and mortality. Numerous surgical strategies exist, but the most frequently used worldwide are adjustable gastric banding, sleeve gastrectomy (SG), and Roux-en-Y gastric bypass (RYGB). It is not clear which of these strategies provides the optimal quality-of-life pay-off.

Relationship between bariatric surgery outcomes and the preoperative gastrointestinal microbiota: a cohort study

BackgroundThe composition of the gastrointestinal microbiota is associated with obesity. We hypothesized that the gut microbiota influences the outcomes of bariatric surgery.ObjectivesWe aimed to analyze using oral swabs and stool samples the microbiota of patients with morbid obesity who were undergoing laparoscopic sleeve gastrectomy (SG).SettingA university hospital in Poland.MethodsThis prospective cohort study was conducted between November 2018 and June 2019. Participants underwent SG or no surgery (controls). Results were then analyzed as a group 1 (surgical participants who achieved a percentage of excess weight loss [%EWL] >50%), group 2 (surgical participants who achieved a %EWL <50%), and group 3 (nonsurgical controls). %EWL was measured 6 months following surgery. Before surgery, oral swabs were obtained and stool samples were provided. The endpoint was the composition of the gut microbiota.ResultsGroup 1 comprised 19 participants, group 2 comprised 11 participants, and group 3 comprised 16 participants. No participants were lost to follow-up during the study. Participants in group 1 had an oral microbiota that was enriched in the phyla Proteobacteria, and Bacteroidetes. Their intestinal microbiota was enriched in the Proteobacteria. In contrast, the oral microbiota of group 2 was enriched in the Actinobacteria and the intestinal microbiota was enriched in the phyla Bacteroidetes and Firmicutes.ConclusionsThe compositions of the microbiota of the oral cavity and large intestine are related to the weight loss achieved following SG.     

Bariatric surgery using a network and teleconferencing to serve remote patients in the Veterans Administration Health Care System: feasibility and results

Background

Previously, Midwestern veteran patients had limited bariatric surgery access because they lived long distances from a bariatric surgery center (BSC). The creation and outcomes of a network to increase bariatric surgery access and patient satisfaction with teleconsultation are discussed.

Methods

Several referring Midwestern Veterans Affairs Medical Centers (VAMCs) performed pre- and postoperative management and were linked by teleconferencing and a computerized patient record system to a single BSC.

Results

Twenty-eight high-risk patients (older, male) residing an average distance of 324.5 miles from the BSC underwent gastric bypass. Eighty-two percent used teleconferencing for the initial surgical consultation with excellent patient satisfaction saving at least 19,000 miles and 69 travel days. Surgical outcomes were equivalent and follow-up was excellent (96.6%) compared with non-Veterans Affairs patients.

Conclusions

A cooperative network using teleconference and computerized records facilitated bariatric surgery in high-risk, remotely located VA patients with high patient satisfaction and without compromising surgical outcomes.     

Effects of bariatric surgery on DNA methylation in adults: a systematic review and meta-analysis

BackgroundDNA methylation is an epigenetic mechanism through which environmental factors, including obesity, influence health. Obesity is a major modifiable risk factor for many common diseases, including cardiovascular diseases and cancer. Obesity-induced metabolic stress and inflammation are key mechanisms that affect disease risk and that may result from changes in methylation of metabolic and inflammatory genes.ObjectivesThis review aims to report the effects of weight loss induced by bariatric surgery (BS) on DNA methylation in adults with obesity focusing on changes in metabolic and inflammatory genes.MethodsA systematic review was performed using MEDLINE, EMBASE, and Scopus, to identify studies in adult humans that reported DNA methylation after BS.ResultsOf 15,996 screened titles, 15 intervention studies were identified, all of which reported significantly lower body mass index postsurgery. DNA methylation was assessed in 5 different tissues (blood = 7 studies, adipose tissues = 4, skeletal muscle = 2, liver, and spermatozoa). Twelve studies reported significant changes in DNA methylation after BS. Meta-analysis showed that BS increased methylation of PDK4 loci in skeletal muscle and blood in 2 studies, while the effects of BS on IL6 methylation levels in blood were inconsistent. BS had no overall effect on LINE1 or PPARGC1 methylation.ConclusionThe current evidence supports the reversibility of DNA methylation at specific loci in response to BS-induced weight loss. These changes are consistent with improved metabolic and inflammatory profiles of patients after BS. However, the evidence regarding the effects of BS on DNA methylation in humans is limited and inconsistent, which makes it difficult to combine and compare data across studies.     

Association between preoperative serum albumin levels with risk of death and postoperative complications after bariatric surgery: a retrospective cohort study

BackgroundHypoalbuminemia is common among individuals with obesity who qualify for bariatric surgery, but its relevance to clinical outcomes after bariatric surgery remains to be established.ObjectivesTo examine the association of preoperative serum albumin with 30-day postoperative outcomes.SettingData from the 2015–2019 Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program Participant Use Files were used.MethodsPreoperative serum albumin level was categorized as hypoalbuminemia (<3.5 g/dL), and normoalbuminemia (3.5–5.5 g/dL) among patients who underwent bariatric surgery. Multivariate logistic regression models were used to determine the association of preoperative hypoalbuminemia with 30-day postoperative mortality and other co-morbid outcomes.ResultsAmong 633,011 adult patients, 85.1% were women and the mean (standard deviation) age was 44.8 (12.0) years. The prevalence of hypoalbuminemia was 6.13% (n = 38,792). After adjustment for procedure type and demographic, lifestyle, and co-morbidity covariates, the odds ratio (OR) (95% confidence interval [CI]) for mortality was 1.42 (1.10, 1.82) for hypoalbuminemia. For all other outcomes, the ORs (95% CIs) for hypoalbuminemia ranged from 1.03 (.67–1.60) for cardiac arrest requiring CPR to 2.32 (1.66–3.25) for failure to be discharged by day 30. The ORs for several associations were higher for severe hypoalbuminemia than marginal hypoalbuminemia.ConclusionPreoperative hypoalbuminemia was associated with several negative 30-day postoperative bariatric surgery outcomes and tended to be worse for severe hypoalbuminemia compared with marginal hypoalbuminemia. These findings suggest that serum albumin may be a useful biomarker to screen for negative bariatric surgery outcomes.     

Assessment of baseline rates of functional and absolute iron deficiency in bariatric surgery candidates: a retrospective study

BackgroundPreoperative optimization of iron status is a priority in candidates for bariatric surgery. Inflammation is strongly associated with obesity, and as a consequence, functional iron deficiency (ID) is potentially an underreported issue in surgical candidates.ObjectivesIn light of updated practice guidelines, to retrospectively review preoperative iron status in an Irish cohort of bariatric surgery candidates, taking account of the relative incidence rate of functional ID.SettingA tertiary care obesity service with bariatric surgery referral in Ireland.MethodsBaseline nutritional biochemistry records were reviewed between February 2017 and February 2020 in a hospital, Dublin, Ireland. Absolute ID was defined as serum ferritin <30 μg/L; functional ID was defined as ferritin, 30 to 100 μg/L, in the presence of C-reactive protein >5 mg/L. Anemia was indexed with reference to hemoglobin and qualified by vitamin B12 and folate status to rule out anemia unrelated to primary ID.ResultsThe analysis included 120 patients, 68% female, 49.6 ± 9.3 years, and body mass index, 52.0 ± 9.6 kg/m². The prevalence of absolute and functional ID was 11.7% and 30.8%, respectively (P = .0003). Anemia was associated with absolute ID and functional ID in 14.3% and 10.8% of patients (P = .29). Folate and vitamin B12 deficiency occurred in <5% of patients.ConclusionIn patients seeking bariatric surgery for severe obesity, the prevalence of baseline functional ID is substantial and can be associated with anemia. These findings raise queries with regard to how best to optimize preoperative iron status in the context of ongoing inflammation.     

Thyroid surgery and obesity: Cohort study of surgical outcomes and local specific complications

Introduction

Obesity is associated with numerous complications after elective general surgeries. The aim is to compare surgical outcomes and local specific complications in obese and non-obese patients after thyroid surgery.

Patterns of physical activity and sedentary behavior after bariatric surgery: An observational study

BackgroundEngaging in low levels of physical activity (PA) and accumulating prolonged periods of sedentary behavior (SB) during daily life have been associated with deleterious health outcomes. The objective of this study was to undertake an analysis of the way in which PA and SB were accumulated after bariatric surgery.MethodsAdults 12 to 18 months after laparoscopic adjustable gastric banding or 6 to 18 months after laparoscopic sleeve gastrectomy wore 2 activity monitors during the waking hours for 7 days. Anthropometric and demographic data were recorded.ResultsData were available on 40 participants (30 females; median ± interquartile range: age 46 ± 16 years, time since surgery 14 ± 8 months, body mass index 36 ± 9 kg/m²). The proportion of waking hours spent in SB, light PA, moderate PA, and vigorous PA was 72% ± 12%, 22% ± 9%, 5% ± 3% and 0% ± 0%, respectively. Half of the time in SB was accumulated in uninterrupted bouts≥30 minutes. Almost all PA was accumulated in bouts<10 minutes in duration. The median daily step count was 9108 ± 4360. The proportion of people who completed an average of≥10,000 steps/d was similar to that reported in Western Australian adults (39% versus 32%; P = .35).ConclusionOur sample spent>70% of time in SB, half of which was accumulated in uninterrupted bouts≥30 minutes. Very little time was spent in moderate or vigorous PA (5%), and this was accumulated in short bouts (<10 minutes). Healthcare professionals should target not just overall time in SB and PA, but also aim to reduce prolonged periods of SB and increase sustained periods of PA.     

Protein and amino acid status before and after bariatric surgery: A 12-month follow-up study

BackgroundPatients with obesity submitted to bariatric surgery present altered ingestion of macronutrient and micronutrient levels and nutrients deficiency. The objective of this study was to evaluate the protein and amino acid nutritional status of obese adults before and after bariatric surgery, with emphasis on plasma free amino acids.MethodsThirty obese women were submitted to Roux-en-Y gastric shunt (bariatric surgery). Food and protein intake, anthropometric and bioimpedance data (body composition analysis), and serum total protein, albumin, and plasma amino acids levels were collected before the surgery (preoperative) and 3, 6, and 12 months after the surgical procedure.ResultsThe mean protein intake was 47±2 g/day. The total weight loss during the study period was 39±8 kg; the fat-free mass decreased 7±5 kg. The amino acid profile showed increased concentrations of most amino acids 3 months after surgery; at 6 months, glutamic acid, serine, arginine, alanine, methionine, valine, phenylalanine, isoleucine, and tyrosine concentrations decreased. The total protein and albumin concentrations dropped along the 12-month follow-up.ConclusionThe amino acid profile changes after RYGB are evidence that total protein and albumin levels may not be good indicators of protein profile after the surgery.