Abstract
Background: Pulmonary dysfunction is reported in patients with β-thalassaemia major but the associations with iron overload and the natural progression remain unclear.
Objectives: To determine the pattern of pulmonary impairment in patients with β-thalassaemia major and their associations with iron overload; and to examine lung function progression of a subgroup over a period of 13 years.
Methods: Subjects with β-thalassaemia major were recruited from four hospitals for full lung function assessment. Serum ferritin and magnetic resonance imaging (MRI) measurements of the liver and myocardium were used as surrogate index of body iron content. This study included 23 subjects who had lung function assessment 13 years ago.
Results: One hundred and one patients were recruited (mean age: 25.1±7.9 years). Thirty-one (30.7%) had restrictive disease and four (4%) had impaired diffusion capacity. There was a significant correlation between the severity of restrictive abnormality and myocardial T2* relaxation time in MRI measurement (r=0.33, p=0.03). Significantly shorter myocardial T2* relaxation time was observed in patients with restrictive disease when compared with those with normal lung function (26.3±14.0ms vs 39.0±18.5ms; p=0.02). Serum ferritin level was inversely correlated with the diffusion capacity (r=-0.32, p=0.002). As a group, 23 subjects did not demonstrate significant changes in pulmonary function over time but 3 patients who had normal lung function at baseline developed restrictive disease at follow-up.
Conclusions: Restrictive deficit is the predominant type of lung abnormality seen in β-thalassaemia major, and the severity correlates with iron overload. Lung function of the majority of patients does not worsen with time.
- Copyright ©ERS 2015