Study On The Relationship Between Thyroid Dysfunction And Severity Of Chronic Obstructive Pulmonary Disease

Objective:The aim of this study is to investigate the correlation between thyroid dysfunction and the severity of chronic obstructive pulmonary disease(COPD).Methods:72 cases of acute exacerbation of chronic obstructive pulmonary disease from outpatient and hospitalized patient in our hospital were selected and analyzed.According to the latest Global Initiative for Chronic Obstructive Lung Disease(GOLD)standard,patients were divided into three groups including group A(Mild,only use short-acting bronchodilator treatment),group B(Moderate,requiring short-acting bronchodilator combination with antibiotics and / or oral hormone therapy),group C(Severe,need hospitalization or emergency treatment,combined with acute respiratory failure)as the objects of observation.There were 23 cases in group A,30 cases in group B and 19 cases in group C respectively.According to the presence or absence of respiratory failure,the AECOPD group was divided into non-respiratory failure group and respiratory failure group.The thyroid function(T3,T4,FT3,FT4,TSH),arterial blood gas analysis were measured in all patients.Lung function(FEV1,FVC,the percentage of FEV1 from FVC,and the percentage of FEV1 from the projected value)before treatment were measured in some of the patients.We also measured the thyroid function and blood gas analysis data in COPD group after treatment.32 healthy subjects were used as the control group with age,sex,and weight matching with patients with chronic obstructive pulmonary disease.Thyroid function information was also tested after treatment.The changes in thyroid function parameters and their correlations with the severity AECOPD before and after treatment were studied.Results:Pulmonary function test results showed that FEV1,FVC,the percentage of FEV1 from FVC,and the percentage of FEV1 from the projected value in group B of AECOPD were significantly reduced compared with those in group A with statistically significance(P < 0.05).In three AECOPD patients groups,the mean value of T3 and FT3 before treatment in these groups was found gradually decreased with the severity of the disease.Among them T3 values in group A was 1.26 ± 0.421(Normal values from 0.89 to 2.49 nmol/L)and FT3 values was 3.53 ± 0.606(Normal values from 2.76 to 6.45 nmol/L).The T3 and FT3 values were 0.93 ± 0.153 and 2.93 ± 0.301 in group B,0.93 ± 0.153 and 2.93 ± 0.301 in group C respectively.There were significant difference in T3 and FT3 between group A and group B,group A and group C,group B and group C(P < 0.05).However,there was no significant difference of T4,TSH and FT4 between A,B and C groups(P > 0.05).With the deterioration of the AECOPD,PaO2 values decreased gradually while PaCO2 increased gradually.PaO2 were positively correlated with T3 and FT3 decrease in contrast to PaCO2 which were negatively correlated with T3 and FT3 decreased.After treatment,the mean value of T3 and FT3 in AECOPD patients groups gradually increased with the relief of the symptoms.The T3 and FT3 values in group A,B and C were 1.39±0.411 and 3.67±0.6;1.1±0.17 and 3.13±0.318;0.82±0.227 and 2.9±0.528.However,Level of T4 and FT4 except TSH in group A was similar compared with those in group B and C(P > 0.05).The T3 and FT3 values in the respiratory failure group were significantly lower in the non-respiratory failure group and the control group(P < 0.05).However,there was no significant difference in T4,TSH and FT4 among respiratory failure group,non-respiratory failure group and the control group(P > 0.05).Conclusion:1 Decreased T3 and FT3 were commonly found in AECOPD patients,but T4,FT4,and TSH basically normal,that is low T3 syndrome.2 The degree of hypoxia in AECOPD patients was positively correlated with the level of T3 and FT3 in contrast to carbon dioxide retention was negatively correlated with T3 and FT3.3 Changes of thyroid hormone levels in AECOPD patients can be used to predict the severity of prognosis of AECOPD.