Micronutrient and Metabolic Status in Morbidly Obese Patients Undergoing Bariatric Surgery in a University Bariatric Program

Iswanto Sucandy, MD, Kurt E Roberts, MD, Geoffrey Nadzam, MD, Andrew J Duffy, MD. Yale University

Background: Bariatric surgery is the most effective long-term treatment for morbid obesity and its associated conditions. Post-operative bariatric surgery patients are known to be at risk for nutritional deficiencies and resulting complications, however, few studies have evaluated nutritional and metabolic status for obesity surgery patients at their preoperative baseline. The objective of this study is to evaluate micronutrient, vitamin, nutritional markers, and metabolic status in patients preparing to undergo their primary bariatric surgery.

Methods: A retrospective review of 225 patients who underwent laparoscopic bariatric operations [Roux-en-y gastric bypass (RYGB), vertical sleeve gastrectomy (VSG), and adjustable gastric banding (AGB)], with preoperative nutritional assessments, between June 2013 and July 2014 was performed. Patients undergoing revisional procedures were excluded from the analysis. Patient’s age, gender, BMI (body mass index), hemoglobin, calcium, albumin, iron, zinc, magnesium, phosphorus, folic acid, and vitamin B12 and D levels were prospectively collected and analyzed as part of the preoperative routine evaluation. Diabetic and dyslipidemic markers were also evaluated to better assess preoperative metabolic health status of these patients. These were collected in fasting patients.

Results: 225 patients (63 RYGB, 153 VSG, 9 AGB) were included in this study with mean age of 43.2 years old (range 15-72), BMI 46.4 kg/m2 (range 35.3-81.4), and gender distribution of 80% female. Deficiencies were found in 22.6% of patients for iron, 19.9% for zinc, 10.7% for calcium, 12.8% for phosphorus, 8.4% for magnesium, and 10.4% for folic acid. In term of preoperative nutritional markers, 13.3% of patients were found to be anemic and 5% were hypoalbuminemic. In the vitamin analysis, 41.7% of subjects had vitamin D deficiency and 1.2% had vitamin B12 deficiency. In the metabolic status assessment, 32% of patients had diabetes mellitus based on HgbA1c value of > 6%, 22.8% had hypercholesterolemia, 55.4% had elevated low density lipoprotein (LDL), and 26.8% had hypertriglyceridemia based on lipid panels.

Conclusions: Pre-bariatric surgery patients demonstrate preoperative micronutrient and vitamin deficiencies, especially for iron, zinc, and vitamin D, in significant proportions. Diabetes and dyslipidemia are common, as previously noted. Protein malnutrition and iron deficiency anemia are notable is 5% and 13.3% of patients, despite their morbidly obesity status. Optimization of nutritional deficiencies preoperatively may be important in surgical recovery and long-term health. The relation to longitudinal nutritional status in these patients after bariatric surgery needs to be further elucidated with structured follow-up.

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