IV Administration More Effective Than Oral Route For Iron Supplementation to Correct Anemia

Author: Michael Vlessides

Anesthesiology News

Although epoetin alfa with iron is frequently administered to anemic patients prior to major orthopedic surgery, there are questions about the optimal route of iron administration.

Now, a team of French researchers has found that following preoperative administration of erythropoietin, both iron stores and erythropoiesis stimulation were greater in patients who received IV ferric carboxymaltose than in their counterparts receiving oral ferrous sulfate supplementation.

“Preoperative anemia is common and one of the riskiest parameters concerning potential mortality and morbidity in noncardiac surgical patients,” said Xavier Capdevila, MD, PhD, a professor and the chair of anesthesiology and critical care medicine at Lapeyronie University Hospital in Montpellier, France. “With this in mind, it is very important to address anemia in the preoperative, intraoperative and postoperative periods.

“The reason why we decided to perform this prospective, randomized trial was to compare the two [administration] methods … in combination with epoetin alfa,” he said.

The two groups of patients were similar on preoperative levels of hemoglobin, ferritin, transferrin saturation and C-reactive protein. Of the initial total of 939 patients, approximately 11% scheduled for total hip or total knee arthroplasty were documented to have anemia. More than half the patients in each surgical group showed anemia with iron deficiency.

This changed markedly by the day prior to surgery, however, which saw greater hemoglobin and serum ferritin levels in patients who received IV iron. Median hemoglobin level at that point was 14.9 g/dL in IV iron patients (interquartile range [IQR], 14.1-15.6 g/dL) and 13.9 g/dL (IQR, 13.2-15.1 g/dL) in oral iron patients (group difference, 0.65 g/dL; 95% CI, 0.1-1.2 g/dL; P=0.017).

Increases in hemoglobin level also were significantly greater in IV iron recipients than in the oral iron group: 2.6 g/dL (IQR, 2.1-3.2 g/dL) versus 1.9 g/dL (IQR, 1.4-2.5 g/dL) (P<0.001). In addition, serum ferritin level was higher in IV iron patients, at 325 mcg/L (IQR, 217-476 mcg/L) versus 64.5 mcg/L (IQR, 44-107 mcg/L) (P<0.001).

“There was always a 1-g/dL difference in hemoglobin levels favoring the IV iron group on days 1, 3 and 5 after surgery,” Dr. Capdevila said. “What was also interesting was when we looked at the production of red blood cells on postoperative day 3, it was negative in the patients receiving oral iron and always positive in the patients receiving intravenous iron.”

“So, as a discussion and conclusion, it is important to keep in mind that the IV group probably represents the best possibility to increase hemoglobin levels in certain patients,” Dr. Capdevila said. “This is what we strive to do in our center: give IV iron supplementation in patients suffering from inflammation, high [body mass index], low baseline hemoglobin, and those in whom we anticipate major blood loss.”

IV Administration Inconvenient, More Expensive

Discussing the findings with Anesthesiology News, Hilary P. Grocott, MD, a professor of anesthesiology, perioperative and pain medicine, and surgery at the University of Manitoba, in Winnipeg, said the findings confirm what has been known for some time: Iron deficiency is a leading cause of preoperative anemia, and replacing iron stores can be an effective way to reduce preoperative anemia, whether through oral or IV administration.

Daniel Bainbridge, MD, a professor of anesthesia and perioperative medicine and director of cardiac anesthesia at Western University’s Schulich School of Medicine & Dentistry, in London, Ontario, agreed that administering IV iron preparations presents challenges that oral iron does not. He noted that new scientific findings may lead to increased absorption of oral iron preparations. “The science behind oral iron seems to be changing, with an eye toward maximizing absorption,” Dr. Bainbridge said.

“As such, there seems to be a trend away from daily iron consumption to every second day,” he added. “Certainly, doing things like taking an iron tablet at night with orange juice, which has lots of vitamin C, can actually increase the uptake of oral iron.”

Nevertheless, Dr. Bainbridge noted that a certain subset of the population can’t tolerate or doesn’t respond to oral iron. “For these people, IV is the obvious choice,” he said.