Endocrine Abstracts

Introduction: A possible association between the severe acute respiratory syndrome coronavirus (SARS-CoV)-2 pandemic, in terms of infection and/or vaccination, and subacute thyroiditis (SAT) has been recently reported. Although a higher SAT incidence in pandemic has been described, data are still conflicting.

Aim: To determine SAT incidence in Italy during the SARS-CoV-2 pandemic and to characterize clinical peculiarities and response to medical treatment of SAT cases, correlating them to virus exposure and/or vaccine.

Methods: We are performing a prospective, longitudinal, observational, 3-year, multi-centre study. All subjects with clinical diagnosis of SAT since November 2020 are enrolled and followed-up for 12 months. During medical history collection, SARS-CoV-2 infection (defined as a positive rhino-pharyngeal swab obtained before SAT onset) and vaccination were recorded. In order to evaluate SAT course, patients were evaluated at 1, 3, 6 and 12 months after onset with thyroid ultrasonography and blood examinations. This is an interim analysis considering baseline visit performed in two centres (Modena and Milan).

Results: A total of 51 subjects (40 females, 11 males) with SAT have been enrolled so far (age: 50.1+11.6 years, BMI: 23.5+3.5 kg/m²). Personal or familiar thyroid disease history was reported in 14 (28%) and 25 (50%) patients, respectively. One (2%) patient had familiar history of SAT. At SAT diagnosis, 36 patients were thyrotoxic (72%) and 5 hypothyroid (10%). TSH serum level was 2.3+7.3 microUI/ml, with mean fT4 20.0+14.0 pg/ml, and fT3 4.8+2.6 pg/ml. Moreover, 30 patients (60%) had elevated erythrocyte sedimentation rate (ESR), 27 (54%) elevated high-sensitivity C-reactive protein (hs-CRP), 12 (24%) high thyroglobulin (Tg) serum levels. The cohort was divided according to either SARS-Cov2 infection (9 patients – 18%) or vaccination (18 patients – 36%). Considering patients with previous infection, the thyrotoxicosis rate raised up to 88.9%. However, the thyrotoxicosis rate (P=0.286), ESR (P=0.520), hs-CRP (P=0.585) and Tg (P=0.178) elevations were not significantly different between patients with or without SARS-Cov2 infection. Similarly, thyrotoxicosis rate (72.2 vs 64.9%, P=0.468), ESR (P=0.268), hs-CRP (P=0.173) and Tg (P=0.712) elevations were not different between patients with or without SARS-Cov2 vaccination.

Conclusion: Our preliminary data suggest that both SARS-CoV-2 infection and vaccination have no impact on the general clinical SAT presentation. Only high thyrotoxicosis rate at diagnosis, especially in patients with previous SARS-CoV-2 infection has emerged. SAT incidence during pandemic will be evaluated at the end of the study.