Background: The prevalence of morbid obesity continues to increase and bariatric surgery remains the superior way to treat morbid obesity and related disorders. Although bariatric surgery can produce significant weight loss and alleviate comorbidities, it can also impact nutritional status in ways that have not been adequately studied.
Objective: The objective of the present study was to compare the incidence of nutritional deficiencies, significant complications, and amount of weight loss in patients undergoing three different bariatric surgery procedures: Vertical Sleeve Gastrectomy (VSG); Roux-en-y Gastric Bypass (RNY-GB); and Biliopancreatic Diversion with Duodenal Switch (BPD-DS). In addition, the role of the registered dietitian (RD) in the outcome of bariatric patients was explored.
Design: A review of all patients undergoing bariatric surgery between April 2006 and December 2007 (n = 119) was conducted from prospectively maintained medical records of a single bariatric surgery practice. Laboratory data related to specific nutrients, hyperlipidemia, and anemia, concerns about compliance with nutrient supplement intake and dietary protein intake, and complication and post-surgery hospitalization rates were compared among patients undergoing the three surgical procedures, VSG, RNY-GB, and BPD-DS. Patients were followed for a minimum of 6 months and a maximum of 18 months after surgery.
Results: Vitamin B12 and calcium deficiency were uncommon after surgery at 1.2% and 2.6%, respectively, among recipients of all surgery types (p = 0.506, and p = 0.092, respectively). The overall rate of folate deficiency was 7.2% and the rate of BPD-DS patients developing folate deficiency after surgery was 37.5% (p = 0.002). The overall rate of anemia was 33.8% and the rate of RNY-GB patients developing anemia following surgery was 50% (p = 0.010). Vitamin D deficiency was markedly high at 66.7% of all patients. All of the BPD-DS patients developed deficiency, which was significantly higher than the other groups (p = 0.003). Protein and vitamin A deficiency were present in 38% and 34.8% of all patients, respectively, but there were no significant differences among surgery types (p = 0.216, and p = 0.141, respectively). Patients who were documented as non-compliant with multivitamin/mineral intake were more likely to develop anemia (p = 0.015) and those who were documented as non-compliant with calcium supplements were more likely to develop vitamin D deficiency (p = 0.022). Weight loss over time among all surgery types was significantly different (p < 0.0001). At 12 months after surgery average percent excess body weight loss (EBWL) was 70.9% for BPD-DS, 59.7% for RNY-GB and 40.2% for VSG. There were no significant differences across groups in the risk of developing complications after surgery relative to weight loss (p = 0.079). Lower albumin levels following surgery were correlated with more complications (r = - 0.31, p = 0.008). RD visits were positively correlated with higher minimum albumin levels (r = 0.24, p=0.025) and greater EBWL (r = 0.30, p = 0.002).
Conclusions: Nutritional deficiencies and anemia occurred as a result of all bariatic surgery procedures, both restrictive (VSG) and malabsorptive procedures (RNY-GB and BPD-DS) in the 18 months post-surgery. The incidence of vitamin D deficiency (66.7%) was particularly concerning. Patient intake of recommended levels of nutrient supplements and dietary protein was poor and was related to some of the nutrient deficiencies and anemia. RD visits were beneficial as more RD visits were related to greater weight loss and higher albumin levels following surgery. Increased RD visits and monitoring of nutritional status, nutrient supplement intake and dietary intake of patients pre and post-bariatric surgery is warranted.