Association of thyroid dysfunction and COVID-19: A systematic review and meta-analysis

This systematic review and meta-analysis was conducted to evaluate the effect of COVID-19 on thyroid function and the role of thyroid hormones alterations in predicting the severity of COVID-19. Online databases, including Scopus, Medline/PubMed, EMBASE, Google Scholar, and Cochrane were searched up to August 2, 2022. After screening titles, abstracts, and full manuscripts, respectively, 30 reports were enrolled. The risk of bias (ROB) was evaluated using the QUADAS-2 tool. In addition, odds ratio (OR) and hazard ratio (HR) analysis for assessing the OR of abnormal thyroid function tests (TFT) in predicting the COVID-19 severity and poor outcomes. Among 30 enrolled studies, ROB of the current study is estimated low to moderate. The average number of patients in each study was 325 (range: 40-3,703), with an overall mean age of 57.6, and the female proportion of 40.4%. Overall, the pooled analysis showed that the prevalence of thyroid dysfunction among 9,707 COVID-19 cases was 15%. Among mild to moderate COVID-19 patients, 6.2% had abnormal TFT, and among patients who experienced severe to critical COVID-19, 20.8% had abnormal TFT. The pooled OR for abnormal TFT and the severity of COVID-19 obtained from 3,865 COVID-19 patients was 3.77 (2.03, 6.99). The pooled HR of TSH level of COVID-19 mortality was 1.57 (0.91, 2.72). Our results demonstrate a high prevalence of thyroid dysfunction in COVID-19, and that among patients severe cases had a 3.77-fold higher risk of abnormal TFT compared to mild to moderate COVID-19. Further studies are required to evaluate the longer-term prognostic role of thyroid dysfunction in severe COVID-19, and investigate potential therapeutic strategies.