ObjectiveTo investigate the association between serum thyroid hormone levels and prognosis for patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) without thyroid disease, and explore the prognostic value of serum thyroid hormone levels for patients with AECOPD.MethodsThe clinical data of 239 hospitalized cases of AECOPD [149 males, 90 females, aged 42-92 (77.7±8.9) years] from January 2013 to November 2017 were retrospectively analyzed. Serum thyroid hormone levels including total tetraiodothyronin (TT4), total triiodothyronin (TT3), thyroid stimulating hormone (TSH), free tetraiodothyronin (FT4) and free triiodothyronin (FT3) were measured by chemiluminescence immunoassay. All patients were divided into a survival group and a death group according to the prognosis. Serum thyroid hormone levels were compared between two groups. Correlations of serum thyroid hormone levels with the occurrence of death in AECOPD patients were analyzed. The prognostic value of serum thyroid hormone levels for AECOPD patients was explored by receiveroperating characteristic (ROC) curve analysis. And the best cut-off value of serum thyroid hormone level in predicting the risk of death was calculated.ResultsSerum TT4, TT3, FT4 and FT3 levels in the survival group were significantly higher than those in the death group [TT4: (89.35±21.45) nmol/L vs. (76.84±21.33) nmol/L; TT3: (1.05±0.34) nmol/L vs. (0.72±0.19) nmol/L; FT4: (16.17±2.91) pmol/L vs. (14.45±2.85) pmol/L; FT3: (3.06±0.81) pmol/L vs. (2.24±0.72) pmol/L; all P<0.05]. The differences of serum TSH level between two groups were not statistically significant [0.98 (0.54-1.83)vs. 0.57 (0.31-1.84), P>0.05]. Spearman correlation analysis showed that serum TT4, TT3, FT4 and FT3 levels were significant correlated with the occurrence of death (r values were 0.226, 0.417, 0.220, 0.387, respectively, P<0.05). And there was no significant correlation between serum TSH level and the occurrence of death (P>0.05). ROC curve analysis was done between serum thyroid hormone levels (TT4, TT3, TSH, FT4 and FT3) and the occurrence of death in the AECOPD patients. The areas under ROC curve were 0.659, 0.793, 0.588, 0.655 and 0.772, respectively. Serum TT3 was the best indicator for predicting the occurrence of death. When serum TT3 level was 0.85nmol/L, the Youden index was the highest (0.486), with a sensitivity of 70.2%, and a specificity of 78.3%. It was the best cut-offl value of serum TT3 to predict the risk of death in AECOPD patients.ConculsionsSerum thyroid hormone levels are significant associated with the prognostic for AECOPD patients. There is certain value of serum thyroid hormone levels in prognostic evaluation of AECOPD patients.