The alterations and clinical significance of serum thyroid hormone levels in patients with acute exacerbation of chronic obstructive pulmonary disease

Abstract

Objective: To observe the alterations of serum thyroid hormone levels in acute exacerbation of chronic obstructive pulmonary disease (AECOPD) patients without thyroid disease and therefore to investigate the association between serum thyroid hormone levels and the severity and prognosis of AECOPD. Methods: Serum thyroid hormone levels including TT4, TT3, TSH, FT4 and FT3 were measured by chemiluminescence immunoassay in 84 hospitalized patients with AECOPD [male 52, female 32, aged 50-93 years, average (78±10) years] and in 35 healthy subjects [male 20, female 15, aged 51-87 years, average (73±11) years] from 2013 to 2014. Results: The serum TT4, TT3 and FT3 levels in AECOPD patients before therapy were significantly lower than those after therapy(P<0.05). The serum TT4, TT3 and FT3 levels in AECOPD post-therapy were significantly lower than those in the healthy control group(TT4: 80±18, 89±18, 113±21; TT3: 0.84±0.25, 1.37±0.31, 1.60±0.35; FT3: 2.57±0.73, 3.49±0.64, 4.21±0.75, P<0.05). The serum FT4 level in AECOPD pre-therapy was significantly lower than that in AECOPD post-therapy and the control group(15.0±2.8, 16.3±2.5, 16.7±2.4, P<0.05). The difference of serum FT4 level between AECOPD post-therapy group and the control group was not statistically significant(P>0.05). The Serum TT4, TT3, FT4 and FT3 levels in type Ⅰ respiratory failure subgroup and type Ⅱ respiratory failure subgroup were both significantly lower than those in the non-respiratory failure subgroup(TT4: 78±14, 70±16, 92±17; TT3: 0.73±0.16, 0.73±0.23, 1.04±0.21; FT4: 14.4±2.4, 14.1±2.4, 16.3±2.9; FT3: 2.27±0.65, 2.32±0.66, 3.05±0.62, P<0.05). The differences of serum TT4, TT3, FT4 and FT3 levels between type Ⅰ respiratory failure subgroup and type Ⅱ respiratory failure subgroup were not statistically significant(P>0.05). The serum TT3 and FT3 levels in the survival subgroup were significantly higher than those in the fatal subgroup(TT3: 0.90±0.25, 0.68±0.18; FT3: 2.76±0.67, 2.07±0.68, P<0.05). The differences of serum TT4(82±18, 75±17), FT4(15.2±2.8, 14.2±2.7) and TSH(1.1±1.1, 1.5±1.5) levels between the 2 subgroups were not statistically significant(P>0.05). Conclusion: Serum thyroid hormone levels are related to the condition of AECOPD. They are reduced in patients with AECOPD and can recover to different degrees as the primary disease improves. Hypoxia and carbon dioxide retention can result in decreased levels of serum thyroid hormones. Serum thyroid hormone levels are significantly associated with the severity and prognosis of patients with AECOPD.