NEW YORK - About a third of heart failure patients have anemia and most also have iron deficiency, according to UK researchers.
This observational analysis, Dr. John G.F. Cleland told Reuters Health by email, "shows that iron deficiency is very common in patients with heart failure and often leads to anemia and that the prevalence of both iron deficiency and anemia are both highly sensitive to the criteria used to define them."
In a June 29 online paper in JAMA Cardiology, Dr. Cleland, of the University of Hull, and colleagues report that they came to this conclusion after studying data on more than 4,400 patients seen at a local clinic over a 10-year period. All were referred because of suspected heart failure, and their median age was 73 years.
Data collected included hemoglobin, serum iron, transferrin saturation, and serum ferritin concentrations.
Overall, 1,237 patients (27.8%) had anemia, with a higher prevalence (33.3%) in patients who met the criteria for heart failure with or without left ventricular systolic dysfunction (LVSD).
Depending on the definition used, iron deficiency was present in 270 (43.2%) to 425 (68.0%) patients with anemia. This was the case in 260 (14.7%) to 624 (35.3%) of those without anemia.
Lower concentrations of hemoglobin (hazard ratio 0.92) and serum iron (HR 0.98) were independently associated with higher all-cause and cardiovascular mortality in multivariable analyses.
Moreover, said Dr. Cleland, "Serum iron and transferrin saturation were highly correlated (raising the question of the need to measure both) and both were strongly related to anemia. In contrast, serum ferritin, the most widely (supposed) measure of iron deficiency, was more strongly related to measures of inflammation than anemia."
"Lower concentrations of hemoglobin and serum iron and lower transferrin saturation," he stressed, "were associated with a higher mortality. In contrast, lower serum ferritin was associated with a better prognosis, probably because it is more a measure of inflammation than of iron deficiency."
Dr. Cleland concluded, "Serum ferritin is a poor measure of iron deficiency in patients with heart failure. Many patients with normal serum ferritin (defined by many as greater than 100 ng/mL) have iron deficiency. Clinical trials of intravenous iron for patients with heart failure should be aware of this issue to ensure they enroll appropriate patients."
The National Heart Service, Vifor Pharma, and Amgen supported this research. Dr. Cleland reported research support from Vifor and Amgen.
JAMA Cardiol 2016.