OPA6 EXPANDING INTERSTITIAL LUNG DISEASE(ILD) BEYOND THE LUNG: A STUDY ON THYROID ANTIBODIES AND THYROID DYSFUNCTION IN PATIENTS WITH ILD

Kezreen Kaur Dhaliwal1, Che Athirah Che Azmi1, Arvindran Alaga1
1Respiratory Department, Hospital Sultanah Bahiyah, Alor Setar, Kedah.

Introduction:

Autoimmune thyroiditis(AT) is common in certain types of ILDs. Hypothyroidism is associated with an increased mortality in idiopathic pulmonary fibrosis(IPF). 

Objectives:

To evaluate the association between ILD and thyroid dysfunction and antibodies. 

Methodology:

This is a retrospective study, involving 20 patients with ILD who are under our review over two years; from March 2022 to March 2024. Thyroid function test and thyroid antibodies [thyroglobulin(TgAb), thyroid peroxidase(TPOAb) and TSH receptor(TRAb) antibodies] were sent for all patients. 

Results :

Majority of patients were females(65%) with median age of 60 years old. Autoimmune-related ILD(55%) was the most common ILD, followed by IIP(35%) and combined pulmonary fibrosis and emphysema(CPFE)(10%). Usual interstitial pneumonia(UIP) pattern was found in 60% of patients. At least one thyroid antibody was detected in 55% of patients, which is higher than general population(5-20%). The positivity of TPOAb, TRAb and TgAb were 35%, 30% and 20% respectively. Three patients had thyroid dysfunction; one subclinical hyperthyroidism, one subclinical hypothyroidism and another one overt hypothyroidism. All patients with CPFE and IPF were positive for thyroid antibodies. IIP patients with positive thyroid antibodies had higher rates of positive ANA/ENA/RF (50% vs 30%, p=0.66), higher ESR (mean:44mm/hr vs 23mm/hr, p=0.09) and CK (mean:100.3U/L vs 88.7U/L, p=0.77) levels, suggesting an autoimmune pathology in these patients. Thyroid antibody positivity did not affect FVC significantly. However, both patients with overt and subclinical hypothyroidism showed substantial decline in their FVC of 10% per year.  

Conclusions:

Thyroid antibodies occur frequently among in ILD patients. ILDs can no longer be considered isolated diseases of the lung. Regular screening for autoimmune thyroiditis should be incorporated when investigating ILD and vice versa. Further research is required to establish the prognostic value of thyroid dysfunction and antibodies.