Effect of thyroid function on COPD exacerbation frequency: a preliminary study

Abstract

BackgroundFrequent exacerbations of chronic obstructive pulmonary disease (COPD) have negative effects on quality of life and survival. Thus, factors related to exacerbations should be determined. We aimed to evaluate the effects of thyroid function on quality of life and exacerbation frequency in COPD patients.MethodsThe study population (n = 128) was divided into 3 groups (Group 1: COPD patients with hypothyroidism (n = 44); Group 2: COPD patients with normal thyroid function tests (n = 44); Group 3: Healthy subjects (n = 40)). Pulmonary function tests, maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP) measurements were performed. Quality of life questionnaire (Short Form 36, SF-36) was carried out. Patients were followed up for one year and number of exacerbations was recorded.ResultsFVC, FEV1/FVC, and FEF 25–75% measurements were statistically different between group 1 and 2 (p = 0.041, p = 0.001, p = 0.009 respectively). Although MEP values were significantly different between group 1 and 2 (p = 0.006), there was no significant difference in MIP values between groups (p = 0.77). Quality of life scores in group 1 and 2 were significantly lower than control group. Exacerbation frequency was significantly higher in group 1 than in group 2 (p = 0.017). TSH values and exacerbation frequency had positive correlation (p < 0.0001; r = 0.82).ConclusionsThe results of the present study suggest that thyroid function has an effect in exacerbation frequency of COPD. Decrease in exacerbation numbers with early detection of impairment in thyroid function will have positive contribution on quality of life in COPD patients.

Thyroid Gland in Chronic Obstructive Pulmonary Disease

“…Another study also confirmed lower values of MEP in COPD patients with hypothyroidism than in those without this condition [31]. The authors observed significantly lower values of FVC, FEV 1 /FVC, forced expiratory flow at 25 and 75% (FEF25-75%) in this group of patients [31]. Others reported on correlation between MEP and MIP values and thyroid function [2].…”

“…The association of free T3 (fT3) level with arterial blood gases and pulmonary function parameters (vital capacity [VC] or forced vital capacity [FVC], FEV 1 , peak expiratory flow [PEF]) has been demonstrated [14]. Another study also confirmed lower values of MEP in COPD patients with hypothyroidism than in those without this condition [31]. The authors observed significantly lower values of FVC, FEV 1 /FVC, forced expiratory flow at 25 and 75% (FEF25-75%) in this group of patients [31].…”

“…Others reported on correlation between MEP and MIP values and thyroid function [2]. Interestingly, there is also a positive correlation between TSH values and acute exacerbations frequency [31]. Among the patients with hypothyroidism, the exacerbations occurred more frequently than in patients without hypothyroidism, and TSH value turned out to be the only significant determinant of exacerbation frequency [31].…”

“…The muscle weakness may manifest in worse spirometry results [2]. In hypothyroidism mean inspiratory pressure (MIP) and mean expiratory pressure (MEP) are decreased [2,31], supposedly due to decreased respiratory muscle strength [33]. The association of free T3 (fT3) level with arterial blood gases and pulmonary function parameters (vital capacity [VC] or forced vital capacity [FVC], FEV 1 , peak expiratory flow [PEF]) has been demonstrated [14].…”

“…However, the exact mechanism of the above connection is not known. Muscle weakness is one of the symptoms of hypothyroidism [2,31]. The deterioration of main respiratory muscle function [32] aggravates already weakened ventilation in patients with COPD [2].…”