Preoperative and Postoperative Assessments of Biochemical Parameters in Patients with Severe Obesity Undergoing Laparoscopic Sleeve Gastrectomy

The study aim was to determine the prevalence of abnormal serum biochemistries associated with micronutrient deficiencies before and after laparoscopic sleeve gastrectomy (LSG). Two hundred and one patients had LSG surgery between May 2011 and May 2014. Using a prospective cohort study design, data were collected on ferritin, hemoglobin (Hgb), mean cell volume (MCV), calcium, albumin, 25-hydroxyvitamin D (25-OH-D), PTH, and vitamin B-12 with follow-up of 75.6% (n = 152), 63.7% (n = 128), 52.7% (n = 106), and 40.3% (n = 81) at 6, 12, 18, and 24 months, respectively. Patients were female (81.6%) with mean +/- SD, BMI (48.8 +/- 6.8 kg/m(2)), weight (135.1 +/- 23.6 kg), and age (44.0 +/- 9.6 years). Mean values for all biochemical parameters pre- and post-LSG were within reference limits. After adjusting for age, weight, and supplement use, trend tests post-LSG were significant for mean differences in ferritin (p = 0.002), calcium (p = 0.017), and vitamin B-12 (p = 0.034). Pre-LSG, the proportion of patients with values below reference limits included 25-OH-D (20.4%), ferritin (12.3%), and Hgb (10.0%), while the proportion above reference limits included PTH (29.1%) and ferritin (17.4%). After adjustment, hypoalbuminemia was more prevalent after 1 year; the proportion of patients with PTH levels in the upper reference limit was higher 6 months post-LSG (p < 0.05). Multivitamin use increased presurgery from 44 to 88% 2 years postsurgery. Vitamin B-12 supplementation increased from 7% before surgery to 32% 2 years postsurgery. Abnormal serum biochemistries indicative of micronutrient deficiencies were prevalent before surgery; reduced abnormal values were observed after surgery, likely due to an increased use of multivitamins.