Among the various post-COVID sequelae, thyroid function impairment stands as a significant concern. COVID-19-related primary hypothyroidism has been documented in the literature. This study aimed to determine the number of cases with subclinical hypothyroidism and a history of moderate COVID-19 pneumonia who progressed to clinically overt hypothyroidism at six months. A prospective case-control study enrolled adult patients with known subclinical hypothyroidism and a history of moderate COVID-19 pneumonia as cases. Detailed medical history and physical examinations were conducted for all participants. Thyroid profiles, including free T4 and TSH, were measured at baseline and again at six months for all cases. The results revealed that 20% of cases with a history of moderate COVID-19 exhibited low free T4 levels at six months following infection, indicating progression from subclinical to clinical hypothyroidism. The mean TSH level at baseline was 7.29 mU/L, which increased to 8.76 mU/L at six months. New-onset symptoms were more prevalent in these cases compared to the controls. Furthermore, the mean baseline TSH level for cases progressing to clinical hypothyroidism was significantly higher (9.17 ± 0.63 mU/L) compared to those who did not progress (6.82 ± 1.16 mU/L; p<0.001). These findings suggest that patients with subclinical hypothyroidism and a history of moderate to severe COVID-19 pneumonia should undergo periodic monitoring to ensure timely treatment initiation if overt hypothyroidism develops.
Chatterjee et al. (Sat,) studied this question.