Subacute thyroiditis at the time of SARS-CoV-2 pandemic

Brancatella, Alessandro; Viola, Nicola; Rutigliano, Grazia; Sgrò, Daniele; Santini, Ferruccio; Latrofa, Francesco

CONTEXT: Acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been related to subacute thyroiditis (SAT). OBJECTIVES: To compare SAT cases at the time of SARS-CoV-2 pandemic to those observed in the previous years. METHODS: A cross-sectional, retrospective study was conducted at the Endocrinology Unit of University-Hospital of Pisa, Italy. We included all patients observed from January 2016 to December 2020 because of an untreated SAT, who had developed the disease within 15 days prior to the visit. SAT cases from 2016 to 2019 (N=152) are referred as “pre-SARS-CoV-2”, while 2020 SAT patients are classified as “pos-SARS-CoV-2” (N=18) or “neg-SARS-CoV-2” (N=28), according to positive or negative test for SARS-CoV-2 performed up to 45 days from SAT onset. RESULTS: While during the years 2016-2019 most SAT cases were observed in the 3 (rd) quarter, in 2020 two peaks, superimposable to the outbreaks of SARS-CoV-2 pandemic of the 2 (nd) and the 4 (th) quarters, were seen. In the 2 (nd) and the 4 (th) quarters of 2020 we observed higher levels of free thyroxine (FT4), C-reactive protein (CRP) and thyroglobulin (Tg) compared to the same quarters of the years 2016-2019. Pos-SARS-CoV-2 had higher FT4 (28.4 vs 24.1 nmol/L), CRP (8.5 vs 3.6 mg/L) and Tg (155 vs 60 μg/L) (P<0.05 for all) and resulted more frequently in hypothyroidism (13/15 vs 30/152 at 3 months) (P<0.001) than to pre-SARS-CoV-2 patients. Neg-SARS-CoV-2 patients showed a clinical picture intermediate between the other two groups. CONCLUSIONS: SARS-CoV-2 pandemic has caused a shift in the annual timing and severity of SAT cases.