Anemia following Roux-en-Y gastric bypass for morbid obesity; a 5-year follow-up study

Iron Treatment in Patients with Iron Deficiency Before and After Metabolic and Bariatric Surgery: A Narrative Review

Iron is an essential nutrient in living organisms with multiple vital functions. Iron deficiency (ID) can cause long term health consequences beyond iron deficiency anemia (IDA). The high prevalence of ID and its long-term effects in patients with obesity and after metabolic and bariatric surgery (MBS) is recognized. Nevertheless, there is limited knowledge of the optimal route or dose for treatment of patients with obesity and post-MBS, and an evidence-based universal guideline for prevention and treatment of ID in short- and long-term post-MBS (PMBS) is not yet available. ID in the general population is currently treated with oral or parenteral iron, where oral iron treatment is considered the preferred option with parenteral iron as a second-line treatment in case there is intolerance or lack of response to oral iron. In patients with obesity with chronic low-grade inflammation and PMBS patients with altered gut anatomy and function, there are also alterations in the bioavailability and higher risks of side effects of available oral irons. The conclusions of current studies exploring effective treatment of iron deficiency in this population have been inconsistent and further well-planned randomized and prospective studies are needed. This is a narrative review of the literature on the available treatment options and strategies for treatment of ID in PMBS patients to recognize the knowledge gaps and provides topics of future research.

Intravenous ferric carboxymaltose is associated with lowering of plasma phosphate levels in patients with gastric bypass surgery: a retrospective case series

AIMS

Bariatric surgery induces several micronutrient deficiencies that require supplementation. For iron, parenteral infusions are usually preferred over oral supplementation. Ferric carboxymaltose infusion has been associated with hypophosphataemia, mostly transient and asymptomatic. However, in some cases, ferric carboxymaltose-induced hypophosphataemia may persist for weeks to months and may induce muscle weakness, osteomalacia and bone fractures. The aim of this study was to identify possible predictors of a clinically relevant decrease in serum phosphate after ferric carboxymaltose infusion in patients with previous Roux-en-Y gastric bypass.

METHODS

Patients with previous Roux-en-Y gastric bypass who received ferric carboxymaltose infusions between January 2018 and September 2019 and had recorded phosphataemia before and after ferric carboxymaltose infusion at the Lausanne University Hospital, Lausanne, Switzerland, were studied retrospectively. A multiple linear regression model was built with delta phosphataemia as the outcome to investigate the factors related to magnitude of serum phosphate lowering.

RESULTS

Seventy-seven patients (70 females and 7 males) with previous Roux-en-Y gastric bypass were studied. Mean age (SD) was 43.2 (10.7) years and median BMI was 30.9 kg/m2 (IQR 27.9-36.4). Sixty-eight patients (88.3%) received an infusion of 500 mg ferric carboxymaltose and 9 patients (11.7%) received 250 mg ferric carboxymaltose. Forty-nine patients (63.6%) developed hypophosphataemia (<0.8 mmol/l) after ferric carboxymaltose infusion. Median plasma phosphate significantly decreased by 0.33 mmol/l (IQR 0.14-0.49) (p<0.0001). Multiple linear regression identified the ferric carboxymaltose dose as the only risk factor significantly associated with the magnitude of serum phosphate lowering, with an additional mean loss of 0.26 mmol/l with a 500 mg infusion compared to a 250 mg infusion (p = 0.020).

CONCLUSION

Ferric carboxymaltose infusions substantially decreased plasma phosphate levels in patients with previous Roux-en-Y gastric bypass. Compared to a dose of 250 mg, infusion of a dose of 500 mg ferric carboxymaltose decreased the plasma phosphate further in this population.

Long-term prevalence of vitamin deficiencies after bariatric surgery: a meta-analysis

BACKGROUND

Bariatric surgery can lead to short-mid-term vitamin deficiencies, but the long-term vitamin deficiencies is unclear. This study aimed to conduct a meta-analysis regarding the long-term prevalence (≥ 5 years) of vitamin deficiencies after bariatric surgery.

METHODS

We searched the EMBASE, PubMed, and CENTRAL databases for clinical studies until June 2023. Meta-analysis, sensitivity, subgroup, and meta-regression analyses were performed.

RESULTS

This meta-analysis included 54 articles with follow-up duration ranging from 5 to 17 years. The most prevalent vitamin deficiencies after surgery were vitamin D (35.8%), followed by vitamin E (16.5%), vitamin A (13.4%), vitamin K (9.6%), and vitamin B12 (8.5%). Subgroup analyses showed that the prevalence of vitamin A and folate deficiencies increased with the follow-up time. Roux-en-Y gastric bypass had a higher rate of vitamin B12 deficiency than sleeve gastrectomy and biliopancreatic diversion with duodenal switch (BPD-DS). Studies conducted in Europe had higher vitamin A deficiency (25.8%) than in America (0.8%); Asian studies had more vitamin B12 but less vitamin D deficiency than European and American studies. Meta-regression analysis displayed that publication year, study design, preoperative age, BMI, and quality assessment score were not associated with vitamin A, B12, D, and folate deficiencies rate.

CONCLUSION

A high prevalence of vitamin deficiencies was found after bariatric surgery in the long-term follow-up, especially vitamin D, E, A, K, and B12. The variation in study regions, surgical procedures, and follow-up time are associated with different postoperative vitamin deficiencies; it is necessary to develop more targeted vitamin supplement programs.

Changes in Nutritional Outcomes After Roux-en-Y Gastric Bypass: A Systematic Review and Meta-Analysis

BACKGROUND

Bariatric surgery (BS) is the most effective treatment for severe obesity and it has beneficial effects on glycemic control and metabolism outcomes. However, the effects of BS on nutritional outcomes are controversial. Therefore, we aimed to evaluate the changes in several nutritional outcomes after Roux-en-Y gastric bypass (RYGB).

METHODS

A comprehensive search was performed using the following databases: PubMed, Embase, Web of Science, Cochrane Library, WanFang and Chinese National Knowledge Infrastructure. The following outcomes were evaluated: vitamin A, 25-hydroxyvitamin D [25(OH)D], calcium, phosphorus, parathormone (PTH), iron, ferritin, vitamin B12, folate, and zinc. The pooled outcomes were expressed as standard mean difference (SMD) and 95% confidence interval (CI) using a random effects model.

RESULTS

Fifty-six studies including 5645 individuals with obesity met the inclusion criteria. Serum 25(OH)D (SMD = 0.78, 95%CI 0.38 to 1.20, P < 0.001), phosphorus (SMD = 0.48, 95%CI 0.22 to 0.74, P < 0.001), PTH (SMD = 0.35, 95%CI 0.11 to 0.59, P = 0.005), vitamin B12 (SMD = 1.11, 95%CI 0.41 to 1.80, P = 0.002), and folate (SMD = 1.53, 95%CI 0.77 to 2.28, P < 0.001) significantly increased after RYGB compared with the baseline. Serum ferritin (SMD =  - 1.67, 95%CI - 2.57 to - 0.77, P < 0.001), vitamin A (SMD =  - 0.64, 95%CI - 0.99 to - 0.29, P < 0.001), and plasma zinc (SMD =  - 0.58, 95%CI - 1.09 to - 0.06, P = 0.027) significantly decreased after RYGB. No significant changes in serum calcium (SMD =  - 0.14, 95%CI - 0.40 to 0.11, P = 0.219) and iron (SMD = 0.26, 95%CI - 0.11 to 0.64, P = 0.165) were observed after RYGB.

CONCLUSIONS

Despite the increased levels of 25(OH)D, phosphorus, vitamin B12 and folate, this meta-analysis revealed the unfavorable nutritional consequences after RYGB.

Diagnosis, Treatment and Long-Term Management of Vitamin B12 Deficiency in Adults: A Delphi Expert Consensus

Background/Objectives: Vitamin B12 deficiency can cause variable symptoms, which may be irreversible if not diagnosed and treated in a timely manner. We aimed to develop a widely accepted expert consensus to guide the practice of diagnosing and treating B12 deficiency. Methods: We conducted a scoping review of the literature published in PubMed since January 2003. Data were used to design a two-round Delphi survey to study the level of consensus among 42 experts. Results: The panelists agreed on the need for educational and organizational changes in the current medical practices for diagnosing and treating B12 deficiency. Recognition of clinical symptoms should receive the highest priority in establishing the diagnosis. There is agreement that the serum B12 concentration is useful as a screening marker and methylmalonic acid or homocysteine can support the diagnosis. Patient lifestyle, disease history, and medications can provide clues to the cause of B12 deficiency. Regardless of the cause of the deficiency, initial treatment with parenteral B12 was regarded as the first choice for patients with acute and severe manifestations of B12 deficiency. The use of high-dose oral B12 at different frequencies may be considered for long-term treatment. Prophylactic B12 supplementation should be considered for specific high-risk groups. Conclusions: There is a consensus that clinical symptoms need to receive more attention in establishing the diagnosis of B12 deficiency. B12 laboratory markers can support the diagnosis. The severity of clinical symptoms, the causes of B12 deficiency, and the treatment goals govern decisions regarding the route and dose of B12 therapy.

Change in Mineral Status After Bariatric Surgery: a Meta-analysis

BACKGROUND

The risk of protein and vitamin deficiencies after bariatric surgery has been well studied, but the change in mineral status has not gotten enough attention. This study aimed to perform a meta-analysis regarding the change in mineral levels after bariatric surgery and the prevalence of postoperative mineral deficiency, with subgroup analyses of different surgical procedures, study regions, and follow-up time.

METHODS

CENTRAL, PubMed, and EMBASE were searched for related articles. Meta-analysis, subgroup analysis, and sensitivity analysis were performed if necessary.

RESULTS

A total of 107 articles with 47,432 patients were included. The most severe mineral deficiency after bariatric surgery was iron (20.1%), followed by zinc (18.3%), copper (14.4%), chlorine (12.2%), phosphorus (7.5%), and calcium (7.4%). Serum concentrations of potassium, sodium, selenium, manganese, and molybdenum showed no significant change before and after surgery. Subgroup analyses revealed that SG had fewer deficiencies in serum iron, calcium, zinc, magnesium, phosphorus, copper, and selenium than RYGB. OAGB showed a higher incidence of serum iron and zinc deficiencies than RYGB. Studies conducted in different regions also found various mineral statuses after surgery. Studies with follow-up ≥ 5 years had a lower prevalence of zinc, copper, and selenium deficiencies than follow-up < 5 years.

CONCLUSION

A high deficiency rate of serum iron, zinc, copper, chlorine, phosphorus, and calcium was seen after bariatric surgery. The difference in surgical procedures, study regions, and follow-up time may affect postoperative mineral status; more targeted mineral supplement programs are needed considering these influencing factors.

Long-Term Outcomes of Iron Deficiency Before and After Bariatric Surgery: a Systematic Review and Meta-analysis

PURPOSE

This study reviews the prevalence of iron deficiency (ID) in bariatric surgery candidates and the long-term outcomes of the prevalence of ID after bariatric surgery.

MATERIALS AND METHODS

A systematic literature search and meta-analysis were performed in PubMed for articles published by August 31, 2022, including these search terms: bariatric surgery, metabolic surgery, weight loss surgery, obesity surgery, sleeve gastrectomy, gastric banding, gastric bypass, duodenal switch, duodenojejunal bypass, iron, iron deficiency, sideropenia, and hypoferritinemia. Fifty-seven studies examining a total of 26,328 patients with morbidly obese were included in this meta-analysis finally.

RESULTS

The results showed a prevalence of 17% of ID in bariatric surgery candidates and a prevalence of 14%, 17%, 26%, 34%, 23%, 38%, and 23% of ID at 1-, 2-, 3-, 4-, 5-, 8-, and 10-year follow-up after bariatric surgery, respectively. Additionally, the results showed a prevalence of 15%, 19%, 35%, 38%, 29%, 30%, and 23% of ID at 1-, 2-, 3-, 4-, 5-, 8-, and 10-year follow-up after Roux-en-Y gastric bypass, respectively; a prevalence of 12%, 12%, 15%, 31%, and 17% of ID at 1-, 2-, 3-, 4-, and 5-year follow-up after sleeve gastrectomy, respectively; and a prevalence of 19% of ID at 1-year follow-up after anastomosis gastric bypass.

CONCLUSION

As a result, preoperative evaluation and correction of ID may lead to better outcomes for bariatric surgery candidates. ID is also common in patients after bariatric procedures, especially RYGB. Long-term, even lifelong, medical and nutritional monitoring and tailored interventions are critical.

The impact of the interplay of the intestinal microbiome and diet on the metabolomic and health outcomes of bariatric surgery

Obesity has evolved into a global epidemic. Bariatric surgery, the most effective treatment for obesity, keeps many comorbidities of obesity at bay for a prolonged period of time. However, complications, including metabolic alterations, are inherent in bariatric surgery. Surgical intervention in the structure of the digestive tract, especially during bariatric bypass procedures, also causes significant changes in the composition of the microbiome, which may affect the composition and quantity of various metabolites produced by intestinal bacteria. The composition of the intestinal microbiome is connected to human metabolism via metabolites that are produced and secreted by bacterial cells into the intestinal lumen and then absorbed into the host's bloodstream. Bariatric surgery causes changes in the composition and quantity of many circulating metabolites. Metabolic disorders may be affected after bariatric surgery by changes in the composition of the microbiome and metabolites produced by bacteria.

Gut microbiome: Linking together obesity, bariatric surgery and associated clinical outcomes under a single focus

Obesity is increasingly prevalent in the post-industrial era, with increased mortality rates. The gut microbiota has a central role in immunological, nutritional and metabolism mediated functions, and due to its multiplexity, it is considered an independent organ. Modern high-throughput sequencing techniques have allowed phylogenetic exploration and quantitative analyses of gut microbiome and improved our current understanding of the gut microbiota in health and disease. Its role in obesity and its changes following bariatric surgery have been highlighted in several studies. According to current literature, obesity is linked to a particular microbiota profile that grants the host an augmented potential for calorie release, while limited diversity of gut microbiome has also been observed. Moreover, bariatric surgery procedures represent effective interventions for sustained weight loss and restore a healthier microbiota, contributing to the observed fat mass reduction and lean mass increase. However, newer evidence has shown that gut microbiota is only partially recovered following bariatric surgery. Moreover, several targets including FGF15/19 (a gut-derived peptide), could be responsible for the favorable metabolic changes of bariatric surgery. More randomized controlled trials and larger prospective studies that include well-defined cohorts are required to better identify associations between gut microbiota, obesity, and bariatric surgery.

British Society of Gastroenterology guidelines for the management of iron deficiency anaemia in adults

Iron deficiency anaemia (IDA) is a major cause of morbidity and burden of disease worldwide. It can generally be diagnosed by blood testing and remedied by iron replacement therapy (IRT) using the oral or intravenous route. The many causes of iron deficiency include poor dietary intake and malabsorption of dietary iron, as well as a number of significant gastrointestinal (GI) pathologies. Because blood is iron-rich it can result from chronic blood loss, and this is a common mechanism underlying the development of IDA-for example, as a consequence of menstrual or GI blood loss.Approximately a third of men and postmenopausal women presenting with IDA have an underlying pathological abnormality, most commonly in the GI tract. Therefore optimal management of IDA requires IRT in combination with appropriate investigation to establish the underlying cause. Unexplained IDA in all at-risk individuals is an accepted indication for fast-track secondary care referral in the UK because GI malignancies can present in this way, often in the absence of specific symptoms. Bidirectional GI endoscopy is the standard diagnostic approach to examination of the upper and lower GI tract, though radiological scanning is an alternative in some situations for assessing the large bowel. In recurrent or refractory IDA, wireless capsule endoscopy plays an important role in assessment of the small bowel.IDA may present in primary care or across a range of specialties in secondary care, and because of this and the insidious nature of the condition it has not always been optimally managed despite the considerable burden of disease- with investigation sometimes being inappropriate, incorrectly timed or incomplete, and the role of IRT for symptom relief neglected. It is therefore important that contemporary guidelines for the management of IDA are available to all clinicians. This document is a revision of previous British Society of Gastroenterology guidelines, updated in the light of subsequent evidence and developments.

Iron supplementation following bariatric surgery: A systematic review of current strategies

Iron deficiency (ID) and iron deficiency anemia (IDA) are common following bariatric surgery; however, there are limited standardized treatment recommendations for their management. The purpose of this study was to review the current strategies for iron supplementation following bariatric surgery and assess their relative efficacy in managing ID and IDA. MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials were searched to January 2021. Primary outcomes of interest were prevention or improvement in ID or IDA with iron supplementation. Forty-nine studies with 12,880 patients were included. Most patients underwent Roux-en-Y gastric bypass (61.9%). Iron supplementation was most commonly administered orally for prevention of ID/IDA and was effective in 52% of studies. Both IV and oral iron were given for treatment of ID/IDA. Fifty percent (3/6) of the oral and 100% (3/3) of the IV supplementation strategies were effective at treating ID. Iron supplementation strategies employed following bariatric surgery are highly variable, and many do not provide sufficient iron to prevent the development of ID and IDA, potentially due to poor patient adherence. Further high-quality prospective trials, particularly comparing intravenous and oral iron, are warranted in order to determine the ideal dosage, route, and duration of iron supplementation.

Post-operative Anemia After Major Surgery: a Brief Review

Purpose of Review

Anemia is a very common complication in the post-operative period. Post-operative anemia is associated with poor outcomes including but not limited to infections, increased length of stay, circulatory overload, and mortality. The strategy of patient blood management focuses on three pillars that include the detection and treatment of pre-operative anemia; reduction of peri-operative blood loss; and harnessing and optimizing the patient-specific physiological reserve of anemia.

Recent Findings

Multiple studies in surgical patients have been conducted to study various methods of management of post-operative anemia. Recent advances in surgical techniques have also been studied to minimize blood loss. There is a widespread consensus on the use of intravenous iron in hospitalized post-operative patients after major surgery.

Summary

We discuss the most common causes of post-operative anemia and management focusing on measures to reduce blood loss and measures to increase red blood cell (RBC) mass. In this brief review, we present updates from the most relevant articles in the past 5 years and include updates from the 2018 international consensus statement on the management of post-operative anemia after major surgical procedures.

Intravenous Iron Treatment in the Prevention of Iron Deficiency and Anaemia After Roux-en-Y Gastric Bypass

Background

Iron absorption is disturbed after Roux-en-Y gastric bypass (RYGB) and iron deficiency with or without anaemia affects almost half of all patients. Intravenous iron is an option when per oral iron is insufficient or not tolerated. This study explores whether routinely offering intravenous iron treatment when iron stores are empty can prevent anaemia and iron deficiency after RYGB.

Methods

This is a study of prospectively registered data on clinical information, haematological tests and intravenous iron treatment from 644 RYGB patients who underwent surgery between 2004 and 2013, postoperatively followed more than 5 years. Intravenous iron treatment was offered to patients with ferritin ≤ 15 μg/L.

Results

Clinical information was available for all patients at baseline and for 553/644 patients at 5 years; laboratory results were available for 540/644 patients at baseline and 411/644 patients after 5 years. The mean age was 39.8 (± 9.7) years. Overall, 187/483 (38.7%) women and 9/161 (5.6%) men were given intravenous iron treatment in the observation period. From baseline to 5 years, mean haemoglobin decreased by 0.3 g/dL in both men and women. Anaemia occurred in 18/311 (5.8%) women and 9/100 (9%) men at 5 years. Depleted iron stores (ferritin ≤ 15 μg/L) were seen among 44/323(13.6%) women and 3/102 (2.9%) men, and low iron stores (ferritin 16–50 μg/L) occurred in 144/326 (44.6%) women and 38/102 (37.3%) men 5 years after RYGB.

Conclusion

By routinely offering intravenous iron treatment to patients with depleted iron stores after RYGB, haemoglobin levels were preserved. Half of the patients experienced low or depleted iron stores at 5 years.

Which Factors Are Associated with a Higher Prevalence of Anemia Following Bariatric Surgery? Results from a Retrospective Study Involving 1999 Patients

INTRODUCTION

Anemia in obese patients is common and multifactorial and is also a complication of bariatric surgery. The aim of this study is to establish which variables are associated with a higher prevalence of post-bariatric surgery anemia.

METHODS

Retrospective cohort study involving 1999 patients submitted to bariatric surgery with a follow-up period of 4 years. Anthropometric, laboratorial parameters and the presence of comorbidities were evaluated before surgery and during follow-up. Patients were divided into two groups, according to whether they developed anemia, or not. Groups were compared using independent sample T-tests or Chi-squared tests, as appropriate. Univariate binary logistic regression models were used to test the association between the diagnosis of anemia during follow-up and all the possible explanatory variables. Independent variables with an association with the outcome (p < 0.1) were included in multivariate binary logistic regression models, as well as possible confounders (age, BMI, and supplementation).

RESULTS

Anemia was diagnosed in 24.4% of the patients. Females present a two-fold increased risk of developing anemia (OR 2.11, 95% CI 1.48-3.01, p < 0.001). Patients subjected to gastric sleeve and gastric band surgery present approximately half the risk of anemia when compared with gastric bypass surgery (RYGB) (OR 0.46, 95% CI 0.35-0.59, p < 0.001; OR 0.51, 95% CI 0.36-0.72, p < 0.001). None of the other variables evaluated showed association with the outcome.

CONCLUSION

In our study, the only factors associated with an increased risk of developing anemia were female gender and RYBG surgery. Prospective studies evaluating the risk factors for anemia in patients undergoing bariatric surgery are needed.

Prevalence of Micronutrient Deficiency after Bariatric Surgery

INTRODUCTION

While vitamin deficiency after bariatric surgery has been repeatedly described, few studies have focused on adequate micronutrient status. In this study, we examine the prevalence of vitamin and micronutrient deficiency for the first 3 years after surgery.

METHODS

Out of 1,216 patients undergoing surgery, 485 who underwent postoperative follow-up in an outpatient clinic between 2010 and 2019 were included in this evaluation (76.9% women, mean age 42 ± 12 years, mean BMI: year 1, 33.9 ± 19.2; year 2, 29.7 ± 8.7; year 3, 26.2 ± 4.0). Weight and cardiovascular risk factors as well as ferritin, vitamin B12, folic acid, 25-OH-vitamin D, vitamin A, vitamin E, zinc, copper, and selenium were evaluated. Deficits were defined as follows: ferritin <15 µg/L, vitamin B12 <197 pg/mL, folic acid <4.4 ng/mL, 25-OH-vitamin D <75 nmol/L, vitamin A <1.05 µmol/L, vitamin E <12 µmol/L, zinc <0.54 mg/L, copper <0.81 mg/L, and selenium <50 µg/L. All patients underwent dietary counselling and substitution of the respective deficits as appropriate.

RESULTS

One year after bariatric surgery, 485 patients completed follow-up. This number decreased to 114 patients in year 2, and 80 patients in year 3. Overall, 42.7% (n = 207) underwent sleeve gastrectomy, 43.7% (n = 211) Roux-en-Y-gastric bypass, and 13.9% (n = 67) gastric banding. The following deficits were found (year 1/2/3): ferritin, 21.6/35.0/32.5%; vitamin B12, 14.3/1.8/6.3%; folic acid, 29.7/21.6/15.3%; 25-OH-vitamin D, 70.8/67.0/57.4%; vitamin A, 13.2/8.9/12.8%; vitamin E, 0%; zinc, 1.7/0/1.5%; copper, 10.4/12.2/11.9%; selenium, 11.1/4.3/0%.

CONCLUSION

As seen in other studies, the follow-up frequency decreased over the years. Despite intensive substitution, the extent of some deficiencies increased or did not improve. These results suggest reinforcing measures to motivate patients for regular follow-up visits, considering closer monitoring schedules, and improving supplementation strategies.

Effect of one-anastomosis gastric bypass on cardiovascular risk factors in patients with vitamin D deficiency and morbid obesity: A secondary analysis

BACKGROUND AND AIMS

Bariatric patients often suffer from vitamin D (VD) deficiency, and both, morbid obesity and VD deficiency, are related to an adverse effect on cardiovascular disease (CVD) risk. Therefore, we assessed the change of known CVD risk factors and its associations during the first 12 months following one-anastomosis gastric bypass (OAGB).

METHODS AND RESULTS

In this secondary analysis, CVD risk factors, medical history and anthropometric data were assessed in fifty VD deficient (25-hydroxy-vitamin D (25(OH)D) <75 nmol/l) patients, recruited for a randomized controlled trial of VD supplementation. Based on previous results regarding bone-mass loss and the association between VD and CVD risk, the study population was divided into patients with 25(OH)D ≥50 nmol/l (adequate VD group; AVD) and into those <50 nmol/l (inadequate VD group; IVD) at 6 and 12 months (T6/12) postoperatively. In the whole cohort, substantial remission rates for hypertension (38%), diabetes (30%), and dyslipidaemia (41%) and a significant reduction in CVD risk factors were observed at T12. Changes of insulin resistance markers were associated with changes of total body fat mass (TBF%), 25(OH)D, and ferritin. Moreover, significant differences in insulin resistance markers between AVD and IVD became evident at T12.

CONCLUSION

These findings show that OAGB leads to a significant reduction in CVD risk factors and amelioration of insulin resistance markers, which might be connected to reduced TBF%, change in 25(OH)D and ferritin levels, as an indicator for subclinical inflammation, and an adequate VD status. REGISTERED AT CLINICALTRIALS.GOV: (Identifier: NCT02092376) and EudraCT (Identifier: 2013-003546-16).

The Correlation Between RDW, MPV and Weight Indices After Metabolic Surgery in Patients with Obesity and DM/IGR: Follow-Up Observation at 12 Months

INTRODUCTION

Red blood cell distribution width (RDW) and mean platelet volume (MPV) are both new biomarkers for the prognosis of many diseases. This study aimed to observe the predictive values of RDW and MPV for weight loss after different metabolic surgeries in patients with obesity and abnormal glucose metabolism [diabetes mellitus or impaired glucose regulation (DM/IGR)].

METHODS

We retrospectively analyzed the body weight (BW), body mass index (BMI) and blood routine index of 98 patients with obesity and DM/IGR who underwent Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG).

RESULTS

Levels of RDW and MPV in both groups were significantly higher than before 1 month after surgery and then gradually decreased. Twelve months after surgery, the RDW level in the RYGB group was significantly lower than that before surgery. In the RYGB group, the RDW level of patients in the high-level percentage weight loss (%BW) (≥ 31.90) at 6 and 12 months after surgery decreased significantly compared to those in the corresponding low level. %BW and change in BW and BMI (ΔBW and ΔBMI) at 6 and 12 months after surgery in the high-level RDW (≥ 12.90) before surgery were significantly higher than those in the low level in the RYGB group. No significant difference in weight index was found in the high and low levels of the MPV before surgery in either group at other follow-up time points.

CONCLUSIONS

Preoperative baseline RDW and postoperative RDW levels can preliminarily predict the effect of different metabolic surgeries in patients with obesity and DM/IGR.

Iron, Vitamin B12, Folate and Copper Deficiency After Bariatric Surgery and the Impact on Anaemia: a Systematic Review

Bariatric surgery may increase the risk of iron, vitamin B₁₂, folate and copper deficiencies, which can cause anaemia. This review aims to critique the evidence on the prevalence of these nutritional deficiencies and the impact on anaemia in the first 12 months after surgery. PRISMA and MOOSE frameworks, the NHMRC evidence hierarchy and The Academy of Nutrition and Dietetics bias tool were used to systematically critique current literature. Seventeen studies reported on deficiency prevalence with the majority being of low quality. Important confounders to serum micronutrient levels were not adequately considered. Results on the prevalence of nutritional anaemias were also lacking. Further investigation into the prevalence of iron, vitamin B₁₂, folate and copper deficiency and its impact on anaemia in bariatric surgery is needed.

Bariatric Surgery in Obesity: Effects on Gut Microbiota and Micronutrient Status

Obesity is associated with reduced gut microbial diversity and a high rate of micronutrient deficiency. Bariatric surgery, the therapy of choice for severe obesity, produces sustained weight loss and improvements in obesity-related comorbidities. Also, it significantly alters the gut microbiota (GM) composition and function, which might have an important impact on the micronutrient status as GM is able to synthesize certain vitamins, such as riboflavin, folate, B12, or vitamin K2. However, recent data have reported that GM is not fully restored after bariatric surgery; therefore, manipulation of GM through probiotics represents a promising therapeutic approach in bariatric patients. In this review, we discuss the latest evidence concerning the relationship between obesity, GM and micronutrients, the impact of bariatric surgery on GM in relation with micronutrients equilibrium, and the importance of the probiotics' supplementation in obese patients submitted to surgical treatment.

Analysis of vitamin levels and deficiencies in bariatric surgery patients: a single-institutional analysis

BACKGROUND

Bariatric surgery patients are at risk for vitamin deficiencies.

OBJECTIVES

Investigate the prevalence of deficiencies of vitamins A, B1, B12, D, and folate in sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) patients in a single institution.

SETTING

An academic medical center.

METHODS

Retrospective chart reviews of 468 bariatric surgery patients (358 SG and 110 RYGB) were analyzed for vitamin levels, calcium, and parathyroid hormone. Both preoperative and postoperative measurements were obtained.

RESULTS

Deficiency of vitamin D was the most common, seen in 27% preoperatively. Postoperatively, RYGB patients had a higher prevalence of vitamin D deficiency than SG patients (11.5% RYGB versus 5.2% SG within the first postoperative year, and 20.3% RYGB versus 13.4% SG after 1 year). Elevated parathyroid hormone was observed in 45% of RYGB patients after 1 year postoperatively. Vitamin A deficiency was uncommon preoperatively (2.7% SG versus 1.7% RYGB), but increased after surgery (9.4% SG versus 15.9% RYGB within 1 year postoperatively, and 5.2% SG versus 7.7% RYGB after 1 year). Vitamin B1 deficiency was observed in 8.1% SG versus 1.7% RYGB patients preoperatively and increased during the first year postoperatively (SG 10.5% and RYGB 13.7%), but improved after 1 year (7.2% SG versus 5.9% RYGB). Less than 2% of Vitamin B12 deficiencies and no folate deficiencies occurred in both SG and RYGB patients.

CONCLUSIONS

The highest prevalence of vitamin B1 and A deficiencies were seen in the first year postoperatively. Vitamin B12 and folate deficiency were uncommon in our patients. Vitamin D deficiency improved after surgery, but elevated parathyroid hormone was common after RYGB.