Subacute THYROiditis Related to SARS-CoV-2 VAccine and Covid-19 (THYROVAC Study): A Multicenter Nationwide Study
Authors: Batman Adnan , Yazıcı Dilek , Dikbaş Oğuz , Ağbaht Kemal , Saygılı Emre Sedar , Demirci İbrahim , Bursa Nurbanu , Ayas Görkem , Anıl Cüneyd , Cesur Mustafa , Korkmaz Fatma Nur , Bahçecioglu Adile Begüm , Çorapçıoğlu Demet , Erdoğan Murat Faik , Bostan Hayri , Calapkulu Murat , Hepşen Sema , Uçan Bekir , Çakal Erman , Güler Bağdagül Yüksel , Haymana Cem , İpekçi Süleyman Hilmi , Aydın Selami , Sezer Havva , Özışık Seçil , Deyneli Oğuzhan , Alagöl Faruk , Tanakol Refik , Eroğlu Mustafa , Mutlu Ümmü , Hacışahinoğulları Hülya , Üzüm Ayşe Kubat , Demir Canan , Koç Gönül , Fırat Sevde Nur , Omma Tülay , İnce Nurcan , Polat Şefika Burçak , Topaloğlu Oya , Aydın Cevdet , Çakır Bekir , Bahadır Çiğdem Tura , Güven Mehmet , Sözen Mehmet , Selek Alev , Cantürk Zeynep , Çetinarslan Berrin , Aydemir Mustafa , Taşkaldıran Işılay , Bozkuş Yusuf , İyidir Özlem Turhan , Haydardedeoğlu Filiz Ekşi , Basmaz Seda Erem , Ünal Mehmet Çağrı , Demir Tevfik , Oğuz Ayten , Çelik Özlem , Yilmaz Merve , Cimsir Aykut , Kayıhan Serdar , Uc Ziynet Alphan , Tekin Sakin , Topaloğlu Ömercan , Saydam Başak Özgen , Ünsal Yasemin Aydoğan , Özer Özge , Yorulmaz Göknur , Uğur Kader , Çakır Sezin Doğan , Aşık Mehmet , Unubol Mustafa , Genc Selin , Andac Burak , Okur Mine , Dogan Ozlem , Karakiliç Ersen , Kocabas Gokcen Unal , Kirac Cem Onur , Cansu Güven Barış , Uygur Meliha Melin , Pekkolay Zafer , Öztürk Sadettin , Güngüneş Aşkın , Gürkan Eren , Keskin Lezzan , Çağlayan Kenan , Günay Yasemin Emur , İmre Eren , Şener Selcuk Yusuf , Kalkan Ahmet Toygar , Gök Deniz Engin , Şahin Mustafa 
Published: April 2023

Abstract

Context
The aims of the study are to compare characteristics of subacute thyroiditis (SAT) related to different etiologies, and to identify predictors of recurrence of SAT and incident hypothyroidism.

Methods
This nationwide, multicenter, retrospective cohort study included 53 endocrinology centers in Turkey. The study participants were divided into either COVID-19–related SAT (Cov-SAT), SARS-CoV-2 vaccine–related SAT (Vac-SAT), or control SAT (Cont-SAT) groups.

Results
Of the 811 patients, 258 (31.8%) were included in the Vac-SAT group, 98 (12.1%) in the Cov-SAT group, and 455 (56.1%) in the Cont-SAT group. No difference was found between the groups with regard to laboratory and imaging findings. SAT etiology was not an independent predictor of recurrence or hypothyroidism. In the entire cohort, steroid therapy requirement and younger age were statistically significant predictors for SAT recurrence. C-reactive protein measured during SAT onset, female sex, absence of antithyroid peroxidase (TPO) positivity, and absence of steroid therapy were statistically significant predictors of incident (early) hypothyroidism, irrespective of SAT etiology. On the other hand, probable predictors of established hypothyroidism differed from that of incident hypothyroidism.

Conclusion
Since there is no difference in terms of follow-up parameters and outcomes, COVID-19– and SARS-CoV-2 vaccine–related SAT can be treated and followed up like classic SATs. Recurrence was determined by younger age and steroid therapy requirement. Steroid therapy independently predicts incident hypothyroidism that may sometimes be transient in overall SAT and is also associated with a lower risk of established hypothyroidism.