Anemia and iron deficiency before and after bariatric surgery.

Background: Iron deficiency and anemia are changes often associated with obesity. Bariatric surgery is responsible for increasing the iron loss and reducing its absorption. The objective of this study was to evaluate anemia and iron deficiency before and after bariatric surgery and to relate them to possible predisposing factors.

Methods: A retrospective study was conducted on obese patients submitted to open Roux-en-Y gastric bypass, in which clinical and laboratory data were obtained up to 48 months postoperatively. Patients were divided into groups according to the presence or absence of anemia and to the presence or absence of iron deficiency (even without anemia), and all data were compared between these groups.

Results: Preoperatively, 21.5% of patients had anemia and 20% had iron deficiency. The number of patients with anemia did not vary through the 4 years of the study, but ferritin levels significantly decreased with time (P<.01). Younger patients and patients with greater weight loss had a higher incidence of anemia. Female gender was a variable associated with a greater incidence of iron deficiency.

Conclusions: Anemia and iron deficiency are frequent in obese patients and must be treated before surgery. Medical and nutritional surveillance is important in the postoperative period of bariatric surgery. Management of each condition must be directed at correcting the 2 major sources of iron deficiency and anemia: food intolerance (mostly meat intolerance) and losses (frequently due to menstruation). These are the factors more related to iron deficient anemia.