Comparison of nutritional deficiencies after Roux-en-Y gastric bypass and after biliopancreatic diversion with Roux-en-Y gastric bypass.

BACKGROUND: Patients undergoing either Roux-en-Y gastric bypass (RYGBP) or biliopancreatic diversion (BPD) with RYGBP are at risk of developing metabolic sequelae secondary to malabsorption. We compared the differences in nutritional complications between these two bariatric operations.

METHODS: A retrospective analysis of a prospective database was done. From June 1994 to December 2001, 243 morbidly obese patients underwent various bariatric procedures at our institution. Of these patients, 79 (BMI 45.6 +/- SD = 4.9) who underwent RYGBP (gastric pouch 15 +/- 5 ml, biliopancreatic limb 60-80 cm, alimentary limb 80-100 cm and common limb the remainder of the small intestine), and 95 super obese (BMI 57.2 +/- 6.1) who underwent a BPD (gastric pouch 15 +/- 5 ml, biliopancreatic limb 150-200 cm, common limb 100 cm and alimentary limb the remainder of the small intestine), were selected and studied for the incidence of micronutrient deficiencies and level of serum albumin at yearly intervals postoperatively. A variety of nutritional parameters including Hb, Fe, ferritin, folic acid, vitamin B12 and serum albumin were measured preoperatively and compared postoperatively at 1, 3, 6, 12, 18 and 24 months, and yearly thereafter.

RESULTS: Nutritional parameters were compared preoperatively and at similar periods postoperatively. No statistically significant (P < 0.05) difference in the occurrence of deficiency was observed between the groups for any of the nutritional parameters studied, except for ferritin, which showed a significant difference at the 2-year follow-up (37.7% low ferritin levels after RYGBP vs. 15.2% after BPD, P = 0.0294). All of these deficiencies were mild, without clinical symptomatology and were easily corrected with additional supplementation of the deficient micronutrient, with no need for hospitalization. Regarding serum albumin, there was only one patient with a level below 3 g/dl in the RYGBP group and two in the BPD group. These three patients were hospitalized and received total parenteral nutrition for 3 weeks, without further complications.

CONCLUSION: There was no significant difference in the incidence of deficiency of the nutritional parameters studied, except for ferritin, following RYGBP vs. BPD with RYGBP. The most common deficiencies encountered were of iron and vitamin B12. The incidence of hypoalbuminemia was negligible in both groups, with mean values above 4 g/dl.