Evaluation of levothyroxine effect on pulmonary function in hypothyroidism

Background and Hypothyroidism is one of the most common diseases in endocrinology Thyroid hormone deficiency effects on nerve and muscle fibers, pulmonary system and alveolar ventilation. The aim of this study was to evaluate the effect of Levothyroxine therapy on pulmonary function in hypothyroidism patients in Imam Hospital. This study was performed on 50 patients with hypothyroidism in Imam Hospital, Sari, Iran, 2006-2007. After a detailed clinical history and systemic examination, level of TSH, T4 and ABG test, chest radiography and spirometery was performed in all patients. The spirometery indexes including FVC, FEV1, FEV1/FVC, FEF 25-75, PEF were recorded. All patients treated with Levothyroxine 1.6μg/kg. After that all systemic and clinical examination, and chest radiography and spirometery performed again. Results analyzed by means of SPSS (11) software and paired t test. The p value less than 0.05 was considered to be significant statistically 50 female patients, with mean age of 34.98±13.4 years were studied. The mean of TSH, T4 before treatment were 51.44±25.3 mIu/l and 2.8± 0.9 μg/dl and after treatment were 3.64±2.4 mIu/l and 9.80±4.9 μg/dl respectively (P= 0.0001). The ABG parameters were in normal range and there was no statistically significant difference between before and after treatment. Statistical analysis demonstrated significant differences between mean of FVC, FEV1, FEV1/FVC, FEF 25-75, and PEF before and after treatment. Our study demonstrates that treatment of hypothyroidism with Levothyroxine can improves the pulmonary function according to spirometery findings.