Is Caruncular Oedema a Reliable Indicator in the Clinical Activity Score for Thyroid Eye Disease? An Analysis of Bias and Observer Variability
Authors' conclusion
Caruncular oedema scoring within the CAS shows poor inter-observer reliability and vulnerability to cognitive and visual biases. Conjunctival and caruncular hyperaemia act as significant confounders, inflating disease activity scores and potentially shifting patients across the CAS threshold (> 3) that guides immunosuppressive treatment. Given these limitations, refinement or replacement of this criterion, through either objective imaging tools or alternative markers such as ocular hypertension, should be considered to improve the reproducibility and diagnostic value of the CAS in both ophthalmology and endocrinology practice.
Study context
- Population
- Thyroid eye disease (TED) patients with standardised photographs773 photographs
- Participants
- 261 patients
- Outcome
- Inter-observer reliability of the caruncular oedema criterion within the Clinical Activity Score (CAS)
Methodological detailsthree independent graders
- Three independent graders
Main finding
As reported in the abstract
Caruncular oedema: slight agreement, κ
0.10
95% CI 0.06–0.15
Conjunctival hyperaemia, κ
0.30
95% CI 0.26–0.35
Observational data: associations, not effects.
Further findings
Sequential vs random reading order (repetition bias)
- Two graders: poor agreement, significant order-related bias
- P = 0.022 and < 0.001
- Third grader: moderate, non-significant agreement, κ (p = 0.147)
- 0.49
- Oedema more often identified in sequential order across graders, consistent with "yes-set" bias
Confounding by caruncular erythema and conjunctival hyperaemia
- Caruncular erythema and conjunctival hyperaemia strongly associated with oedema scoring; red or congested caruncle markedly increased false-positive oedema calls
Original publication
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