Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 50 8 2021 07 21 1517 1525 EN Juan Xu Department of Internal Medicine, The People’s Hospital of Guandu District, 63 Yingfeng Road, Kunming 650200, China Yang Li Department of Clinical Laboratory, The Third Affiliated Hospital of Kunming Medical University, 519 Kunzhou Road, Kun-ming 650118, China Quansong Xia Department of Clinical Laboratory, The Third Affiliated Hospital of Kunming Medical University, 519 Kunzhou Road, Kun-ming 650118, China Qiong Shi Department of Clinical Laboratory, The Third Affiliated Hospital of Kunming Medical University, 519 Kunzhou Road, Kun-ming 650118, China 2021 04 16 2021 05 06 Background: COVID-19 has resulted in an emerging respiratory infection with a pandemical diffusion since December 2019. We aimed to elucidate whether the presence of thyroid disease might increase the risk of severe COVID-19 infection. Methods: Studies reporting seriously ill in COVID-19 patients with and without thyroid disease combined were searched and 11 relevant studies were subjected to our analysis, and pooled odds ratios (ORs) together with 95% confidence intervals (CIs) were calculated by using STATA and Review Manager Software. Results: In total, 2,995 COVID-19 patients were included in this study. The pooled ORs were calculated using a fixed-effects model according to the heterogeneity. The pooled results revealed that thyroid disease was associated with severe COVID-19 infection in patients (OR = 2.14, 95 % CI: 1.23–3.72, P = 0.007). In the subgroup analysis by type of thyroid disease, hypothyroidism was positively associated with risks of severe COVID-19 infection (OR = 4.78, 95 % CI: 1.59–14.36, P = 0.005), however, no obvious difference was found in the risk regarding the severe COVID-19 infection amongst hyperthyroidism or unclassified thyroid disease. In addition, subgroup analysis stratified by ethnic groups demonstrated that thyroid disease was linked to the risks of severe COVID-19 infection in Asian patients (OR = 2.41, 95 % CI: 1.30–4.48, P = 0.005) rather than non-Asian (OR = 1.31, 95 % CI: 0.35–4.87, P = 0.684). Conclusion: This study indicates a correlation between thyroid disease and severe COVID-19 infection. https://ijph.tums.ac.ir/index.php/ijph/article/view/24594 https://ijph.tums.ac.ir/index.php/ijph/article/download/24594/7309