New concepts in the diagnosis and management approach to iron deficiency in candidates for metabolic surgery: should we change our practice?

The near universal presence of chronic low-grade systemic inflammation among patients with severe obesity disrupts iron homeostasis and underlies the association between obesity and iron deficiency. Immune activation and inflammation result in a reduction in circulating iron and diminished iron bioavailability for erythropoiesis. Inflammation also alters blood levels of commonly measured markers of iron nutrition status, which makes the diagnosis of iron deficiency difficult and has led to new recommendations regarding laboratory markers for the diagnosis. Recent evidence using these newly recommended laboratory markers, which include levels of ferritin, C-reactive protein, and transferrin saturation, suggests that the actual prevalence of iron deficiency among candidates for metabolic surgery may be double or triple the prevalence identified by low levels of ferritin alone. Thus large numbers of surgical candidates have iron deficiency that has been heretofore largely unrecognized and inadequately treated. The assessment of iron status using the currently recommended markers in the presence of chronic inflammatory diseases and repletion of depleted stores for surgical candidates with deficiency during the preoperative period present an important opportunity for mitigating this condition in postoperative patients.