Thyroid eye disease (TED) phenotype varies by ethnicity/race and genetic/environmental factors. This study compared demographic and clinical characteristics of TED patients from the US and India.

Observational pilot study .

Sixty-four patients with TED ages ≥18 years old with active disease (onset of symptoms ≤18 months or presenting clinical activity score (CAS) ≥4) were recruited between March and October 2021 from clinical practices in the United States (Philadelphia, PA) (n = 30) and India (Hyderabad, India) (n = 34). Data collection at baseline and 3 months included clinical measurements, thyroid disease history, and photographs. Ocular symptoms and quality of life data were obtained by phone interview. CAS was calculated using the standard 7-point scale.

There was no statistically significant difference in age, TED duration, or smoking status between patient groups. Both groups had good vision, a low rate of optic neuropathy, and comparable exophthalmometry. US patients were predominantly female (86.7% [26/30]), with a history of hyperthyroidism (96% 29/30). In comparison, Indian patients were 52.9% (18/34, P = .004) female; underlying thyroid disease was distributed between hyperthyroidism (52%), hypothyroidism (17.6%) and euthyroid (9.7%). Mean (SD) CAS in the US cohort was double the score in the India cohort (4.2 (1.7) vs 1.65 (1.7), respectively) (P < .0001). However, patients at both sites experienced subjective symptoms of TED at a similar frequency.

Observed differences in TED between US and Indian patients warrant further investigation to elucidate differences in pathogenesis, disease expression, or other factors that may influence TED in diverse populations.