Abstract
Patients with chronic hypoxaemia develop a physiologically appropriate secondary polycythaemia that improves oxygen carrying capacity. Therefore, normal haemoglobin and haematocrit values in the presence of chronic arterial hypoxaemia in cystic fibrosis constitute 'relative anaemia'. We sought to determine whether relative anaemia in cystic fibrosis is iron deficiency anaemia or anaemia of chronic disease. We studied haematological indices and oxygen saturations at rest and during exercise in healthy volunteers (n=17), and in 2 groups of patients with conditions characterized by chronic hypoxaemia, cystic fibrosis (n=15) and Eisenmenger syndrome (n=5). Haemoglobin and haematocrit values in patients with cystic fibrosis did not differ significantly from normal volunteers. However, serum iron (p=0.002), transferrin (p=0.02), and total iron binding capacity (p=0.01) were lower in patients with cystic fibrosis. There were no significant differences in serum ferritin, percentage iron saturation, serum erythropoietin or red cell volume compared to normal volunteers. These results suggest anaemia of chronic disease. In contrast, in patients with Eisenmenger syndrome, haemoglobin (p=0.0004) and haematocrit values (p<0.0001), serum transferrin (p=0.02), total iron binding capacity (p=0.0008), serum erythropoietin (p<0.0001) and red cell volume (p<0.0001) were significantly higher than those of normal volunteers. Serum ferritin (p=0.006), serum iron concentrations (p=0.02) and percentage iron saturation (p=0.006) were lower than those of normal patients. These results suggest iron deficiency anaemia. Normal haemoglobin and haematocrit values seen in patients with cystic fibrosis represent a combination of arterial hypoxaemia leading to a tendency to polycythaemia counterbalanced by chronic inflammation leading to anaemia of chronic disease.
Original language | English |
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Pages (from-to) | A65 |
Journal | Thorax |
Volume | 55 |
Issue number | SUPPL. 3 |
Publication status | Published - Dec 2000 |
Externally published | Yes |