Anaemia in patients with self-reported use of iron supplements in the BAriatric surgery SUbstitution and nutrition study: A prospective cohort study.

BACKGROUND AND AIMS: After bariatric surgery, micronutrient deficiencies may lead to anaemia. To prevent post-operative deficiencies, patients are recommended lifelong micronutrient supplementation. Studies investigating the effectiveness of supplementation to prevent anaemia after bariatric surgery are scarce. This study aimed to investigate the relationship between nutritional deficiencies and anaemia in patients who report use of supplementation two years after bariatric surgery versus patients who do not. METHODS AND RESULTS: Obese (BMI≥35 kg/m2) individuals (n = 971) were recruited at Sahlgrenska University Hospital in Gothenburg, Sweden between 2015 and 2017. The interventions were Roux-en-Y gastric bypass (RYGB), n = 382, sleeve gastrectomy (SG), n = 201, or medical treatment (MT), n = 388. Blood samples and self-reported data on supplements were collected at baseline and two years post treatment. Anaemia was defined as haemoglobin <120 g/L for females and <130 g/L for males. Standard statistical methods, including a logistic regression model and a machine learning algorithm, were used to analyse data. The frequency of anaemia increased from baseline in patients treated with RYGB (3·0% vs 10·5%; p < 0·05). Neither iron-dependent biochemistry nor frequency of anaemia differed between participants who reported use of iron supplements and those who did not at the two-year follow-up. Low preoperative level of haemoglobin and high postoperative percent excessive BMI loss increased the predicted probability of anaemia two years after surgery. CONCLUSION: The results from this study indicate that iron deficiency or anaemia may not be prevented by substitutional treatment per current guidelines after bariatric surgery and highlights there is reason to ensure adequate preoperative micronutrient levels. TRIAL REGISTRATION: March 03, 2015; NCT03152617.

Vitamin status after bariatric surgery: a randomized study of gastric bypass and duodenal switch.

BACKGROUND: Bariatric surgery is widely performed to induce weight loss. OBJECTIVE: The objective was to examine changes in vitamin status after 2 bariatric surgical techniques. DESIGN: A randomized controlled trial was conducted in 2 Scandinavian hospitals. The subjects were 60 superobese patients [body mass index (BMI; in kg/m(2)): 50-60]. The surgical interventions were either laparoscopic Roux-en-Y gastric bypass or laparoscopic biliopancreatic diversion with duodenal switch. All patients received multivitamins, iron, calcium, and vitamin D supplements. Gastric bypass patients also received a vitamin B-12 substitute. The patients were examined before surgery and 6 wk, 6 mo, and 1 y after surgery. RESULTS: Of 60 surgically treated patients, 59 completed the follow-up. After surgery, duodenal switch patients had lower mean vitamin A and 25-hydroxyvitamin D concentrations and a steeper decline in thiamine concentrations than did the gastric bypass patients. Other vitamins (riboflavin, vitamin B-6, vitamin C, and vitamin E adjusted for serum lipids) did not change differently in the surgical groups, and concentrations were either stable or increased. Furthermore, duodenal switch patients had lower hemoglobin and total cholesterol concentrations and a lower BMI (mean reduction: 41% compared with 30%) than did gastric bypass patients 1 y after surgery. Additional dietary supplement use was more frequent among duodenal switch patients (55%) than among gastric bypass patients (26%). CONCLUSIONS: Compared with gastric bypass, duodenal switch may be associated with a greater risk of vitamin A and D deficiencies in the first year after surgery and of thiamine deficiency in the initial months after surgery. Patients who undergo these 2 surgical interventions may require different monitoring and supplementation regimens in the first year after surgery. This trial was registered at ClinicalTrials.gov as NCT00327912.