ABSTRACT
OBJECTIVE: There is an increasing body of literature on the impact of COVID-19 on the pituitary-thyroid axis. Therefore, we conducted a systematic review to assess the prevalence of hypothyroidism in patients with COVID-19. METHODS: A literature review was conducted using LitCOVID for study selection in PubMed and MEDLINE till May 2021. All relevant original articles evaluating thyroid dysfunction were included and information regarding the prevalence of hypothyroid disease in COVID-19 was retrieved from the eligible articles. RESULTS: Out of 32 articles, six articles qualified for the final analysis which included 1160 patients. There was significant heterogeneity among the included articles. Most of the patients had lower mean triiodothyronine (T3) and normal or low thyroid-stimulating hormone (TSH). Increased TSH ranged from 5.1% to 8% while low T3 was present in up to 28% of the patients. In these studies, the prevalence of altered thyroid hormones was significantly more in COVID-19 patients as compared to control groups. A positive correlation between low mean T3 and clinical severity of COVID-19 was reported. CONCLUSION: This systematic review reveals a significant proportion of hypothyroidism associated with COVID-19. Therefore, routine assessment of thyroid function is warranted in hospitalized COVID-19 patients.