Evaluation of pulmonary function in beta-thalassemia major patients

ABSTRACT

To describe and quantify the functional change of the lung in patients with beta-thalassemia major [TM] and determine the correlation between pulmonary function test [PFT] results with hemoglobin, ferritin and age changes. Pulmonary function tests were performed on 60 transfusion-dependent patients with TM, ranging in age from 10 to 45 years. Percent-predicted values for forced expiratory volume in one second [FEV1], and forced expiratory flows [FEF] 25-75% were significantly reduced, whereas forced expiratory vital capacity [FVC] and FEV1/FVC were closed to normal limits, indicating a restrictive disease. All factors including; FVC, FEV1, and FEV1/FVC, FEF 25-75% were negatively correlated with age and ferritin levels. In contrast, all factors including; FVC, FEV1, and FEV1/FVC, FEF 25-75% were positively correlated with hemoglobin [Hb]. We performed linear regression analysis to study the simultaneous influence of the presence of age, ferritin, and Hb on obstructive PFT indexes. Pulmonary function test results were normal in only 32 [53.3%] of 60 patients and the rest 28 cases [46.7%] showed abnormal pulmonary function. FEV1 and FEF25%-75% have significant negative correlation with age [r=- 0.64 p[r]=0.003 and r=- 0.58 p[r]=0.02 respectively], also have significant positive correlation with Hb [r=0.31 p[r]=0.015 and r=0.33 p[r]=0.01 respectively], and only FEF25%-75% has significant negative correlation with ferritin [r=-0.26 p[r]=0.04]. The present study has shown that restrictive disease and reduced lung diffusing capacity are the predominant abnormalities of pulmonary function in patients with TM. The low hemoglobin concentration and a fall in the diffusing capacity of the alveolar-capillary membrane, together with the dependence of the reduced pulmonary diffusing capacity on age and serum ferritin levels, as well as of the entity of restrictive disease on age, suggests that pulmonary dysfunctions in patients with TM are due mainly to lung fibrosis and/or interstitial edema related to iron overload