The association between subclinical hypothyroidism and exacerbation in patients with chronic obstructive pulmonary disease

This study aimed to investigate the association between subclinical hypothyroidism and exacerbation in patients with chronic obstructive pulmonary disease (COPD). This descriptive-analytical study was performed on patients with COPD that were diagnosed by spirometry and GOLD guides. A modified medical research council (mMRC) questionnaire was also used for grading dyspnea. The severity of the disease was determined according to the GOLD criteria. Patients were divided into mild, moderate, severe, and very severe COPD. Then, the patients were included in high-risk (C and D) and low-risk (A and B) groups. Thyroid-stimulating hormone (TSH), free thyroxine, triiodothyronine (T3), and T3 resin uptake tests were assessed. Out of 119 patients with COPD, about 74.8% were males and 25.2% were females. Overall, 50.4% of participants were in an exacerbation state and 49.6% were stable. A significant association was reported between the number and years of cigarette smoking and the exacerbation of COPD (P0.05). There was a significant association between severity in exacerbation and stable groups (P 0.05). The frequency of dyspnea grade with high mMRC scores in the exacerbation group was higher than in the stable group. The mean difference in FEV1, FVC, FEV1/FVC, and T3 variables was significant between the two studied groups. There was a significant difference between the variables of "one-year hospitalization", "one-year exacerbation" and "duration of illness" among the two groups of stable and exacerbation (P0.05). It’s suggested that the mean level of T3 could be used in the future to predict disease exacerbation in COPD.