title: The modified iron avidity index: a promising phenotypic predictor in HFE-related haemochromatosis.
abstract: Phenotypes of the HFE-related haemochromatosis vary considerably, making it hard to predict the course of iron accumulation. The aim of this retrospective study was to determine if the Iron Avidity Index (IAI) is a good phenotypic predictor of the number of phlebotomies needed per year during maintenance treatment (NPDMT) in patients with homozygous p.C282Y hereditary haemochromatosis (HH).
  
  
  
  Patients with HH homozygous for p.C282Y, on maintenance treatment for at least 1 year were included. The IAI (ferritin level at diagnosis/age at diagnosis) was calculated.
  
  
  
  Ninety-five patients were included in the analysis. Linear regression analysis showed the confounding effect of sex on the relationship between IAI and NPDMT. A modified IAI, adjusted for sex, was calculated. As proton pump inhibitor (PPI) use was independently associated with NPDMT, the group was split in PPI- and non-PPI-users. A positive correlation between the modified IAI and the NPDMT was shown in both groups (PPI r = 0.367, P = 0.023; non-PPI r = 0.453, P < 0.001). An ROC was computed to measure the accuracy of the modified IAI to predict who needed 0-2 vs. ≥3 maintenance treatments per year. The AUROC in the PPI and non-PPI group were respectively 0.576 (0.368-0.784) and 0.752 (0.606-0.899).
  
  
  
  The modified IAI is a fairly good predictor in non-PPI-using homozygous C282Y HH patients, to differentiate who needs ≥3 maintenance phlebotomies per year. Therefore, this index might help to select patients that benefit from an alternative less frequent therapy, e.g. erythrocytapheresis.
authors.affiliation: Maastricht University Medical Center, Department of Internal Medicine, Division of Gastroenterology and Hepatology, Maastricht, the Netherlands.
authors.forename: Pauline L M
authors.initials: PL
authors.lastname: Verhaegh
authors.affiliation: Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, the Netherlands.
authors.forename: Wenke
authors.initials: W
authors.lastname: Moris
authors.affiliation: Maastricht University Medical Center, Department of Internal Medicine, Division of Gastroenterology and Hepatology, Maastricht, the Netherlands.
authors.forename: Ger H
authors.initials: GH
authors.lastname: Koek
authors.affiliation: Maastricht University Medical Center, Department of Internal Medicine, Division of Gastroenterology and Hepatology, Maastricht, the Netherlands. c.van.deursen@atriummc.nl.|Zuyderland Medical Center, Department of Internal Medicine, Gastroenterology and Geriatrics, Heerlen, the Netherlands. c.van.deursen@atriummc.nl.
authors.forename: Cees Th B M
authors.initials: CT
authors.lastname: van Deursen
mesh_terms: D000368:Aged; D005260:Female; D005293:Ferritins / Q000097:blood*; D006432:Hemochromatosis / Q000235:genetics / Q000628:therapy*; D000071020:Hemochromatosis Protein / Q000235:genetics; D006720:Homozygote; D006801:Humans; D007501:Iron / Q000378:metabolism*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D018962:Phlebotomy; D054328:Proton Pump Inhibitors / Q000627:therapeutic use*; D012372:ROC Curve; D012189:Retrospective Studies; D012720:Severity of Illness Index
chemical_list: C103673:HFE protein, human; D000071020:Hemochromatosis Protein; D054328:Proton Pump Inhibitors; D005293:Ferritins; D007501:Iron
keywords: C282Y; hereditary haemochromatosis; maintenance treatment; phenotypic predictor; phlebotomy