Low clinical activity score, ‘progressive’ thyroid eye disease: presentations of 1439 patients from a tertiary centre in Hong Kong

Background To report the presenting clinical, serological and treatment profiles of 1439 patients with thyroid eye disease (TED) from a tertiary centre in Hong Kong. Study populations Consecutive patients with TED presented to the Thyroid Eye Clinic (TEC), the Chinese University of Hong Kong between 2014 and 2023. Methods Prospective cohort and masked review of medical records and orbital images. Results A total of 1439 (70% female, 98% Han Chinese) patients with TED (26% ex/current smoker), presented at 43±5.9 years old, were reviewed. The first TED symptoms to TEC evaluation was 6±3 months. 85% had Graves’ disease and 12% were given radioactive iodine before presentation. 35% of patients had a family history of autoimmune thyroid diseases. Baseline thyroid-stimulating hormone receptor antibody, thyroid-stimulating immunoglobulin and thyroid peroxidase antibody were elevated in 75%, 69% and 57% tested. Euthyroid TED (E-TED) was diagnosed in 6%, associated with asymmetric presentation (p<0.001). The most common signs were exophthalmos (69%), upper eyelid retraction (53%), swelling (36%), conjunctival injection (34%) and lower eyelid retraction (32%). Notably, 547 (38%) presented with moderate-to-severe and 150 (10%) vision-threatening TED, whose clinical activity score (CAS) was just 2.4±1.4 and 2.6±1.5, respectively. Male and TED onset after 40 were associated with higher CAS and NOSPEC (No physical signs or symptoms, Only signs, Soft tissue involvement, Proptosis, Extraocular muscle signs, Corneal involvement, and Sight loss) score (both p<0.05). 471 (33%), 361 (25%), 263 (18%) and 138 (9%) patients received intravenous methylprednisolone, orbital radiotherapy, steroid-sparing immunosuppressants and surgical decompression, respectively. Conclusions Around one-third (34%) of our cohort presented with ‘low-CAS, progressive’, moderate-to-severe or vision-threatening TED, while only one-fifth (18%) were clinically active (CAS≥3). Our results showed the limitations and unmet need of the existing ‘high-CAS only’ approach, especially in managing ‘non-inflammatory’ TED, prevalent in non-Caucasian populations.