Endocrine Abstracts

Background

Subacute thyroiditis (SAT) has been related to acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We evaluated the incidence and the severity of SAT due to SARS-CoV-2.

Methods

A cross-sectional, retrospective study was conducted at the Endocrinology Unit of University-Hospital of Pisa, Italy. All patients experiencing SAT arisen within a period of 15 days earlier and yet untreated, assessed from January 2016 to December 2020, were included in the study. SAT cases from 2016 to 2019 (n = 152) were defined as “pre-SARS-CoV-2”, while 2020 SAT patients were classified as “pos-SARS-CoV-2” (n = 13) or “neg-SARS-CoV-2” (n = 24) according to positive or negative test for SARS-CoV-2 at SAT onset or within a period of 45 days earlier.

Results

While in the years 2016–2019 most SAT cases were observed in the 3rd quarter, in 2020 there were two peaks, in the 2nd and in the 4th quarters, superimposable to the two main outbreaks of SARS-CoV-2. Compared to the same quarters of the years 2016–2019, in the 2nd and the 4th quarters of 2020 we observed higher levels of free thyroxine (FT4), C-reactive protein (CRP) and thyroglobulin (Tg). Compared to pre-SARS-CoV-2, pos-SARS-CoV-2 had higher FT4 (28.1 vs 24.1 nmol/l), CRP (8.0 vs 3.6 mg/l) and Tg (155 vs 60 µg/l) (P<0.05 for all) and resulted more frequently in hypothyroidism at 3 months (9/10 vs 30/152) (P <0.001). Neg-SARS-CoV-2 patients showed a clinical picture intermediate between pre-SARS-CoV-2 and pos-SARS-CoV-2 patients.

Interpretation

Most SAT cases in 2020 were associated with SARS-CoV-2 infection and were more severe than those previously observed.

Funding

This study was supported by “Fondi di Ateneo”, University of Pisa.