Assessment of the respiratory muscles strenght in beta-thalassemia

Intolerance to exercise still remains a common feature in beta-thalassemia patients (BT), despite the transfusional regimen and iron chelation therapy. The most frequent spirometric deficit reported is of restrictive type, but the relative contribution by the lung parenchima and by the chest wall and respiratory muscles is unknown. We studied 27 BT patients (14M, 39.52±12.77 y) and 17 healthy subjects (7M, 32.25±10.69 y). We obtained the classical spirometric parameters and enrolled only BT patients having normal values. Measurements of maximal inspiratory and maximal expiratory pressure (MIP and MEP) at or near RV and TLC, respectively, were also performed. Statistical significance of differences betweeen groups was assessed by Student t-test, considering significant a p< 0.05. Previous studies showed a diminished exercise capacity in BT patients. Our data confirm these reports and suggest that BT patients, in spite of showing normal respiratory function values, may have a weakness in their respiratory muscles, probably due to iron deposition.