Anemia Before and After Roux-en-Y Gastric Bypass: Prevalence and Evolution on Long-Term Follow-up

Anemia due to iron deficiency or inflammatory state is often associated with obesity. Bariatric surgery is responsible for increasing iron deficiency, but weight loss decreases the inflammatory state associated with obesity. The objective of our study was to investigate the prevalence and causes of anemia before and after bariatric surgery for severe obesity in a 5-year follow-up.

Retrospective study, with electronic record analysis of obese patients, submitted to Roux-en-Y gastric bypass. Laboratory data were collected before and up to 60 months after surgery. Diagnosis and classification of anemia were done according to hemoglobin levels, serum ferritin, and transferrin saturation.

Preoperatively, 8.8% of patients had anemia (93.2%, mild), and 43.8% of the patients had anemia due to chronic disease. After 24 months, there was a progressive increase of iron-deficiency anemia (72.4%) and decrease in anemia due to chronic disease (15.5%) and mixed (12.1%), with maintenance of this profile during long-term follow-up.

Anemia is very frequent in severely obese patients and must be investigated both before and after bariatric surgery. The cause of anemia must be determined in order to use the best treatment available. We observed a reduction in the prevalence of chronic disease anemia during long-term follow-up probably due to the improvement in the systemic inflammatory state.