Predictive demographic and clinical features for the development of dysthyroid optic neuropathy in a multi-ethnic TED population: a retrospective cohort study.

Background: Dysthyroid Optic Neuropathy (DON) is a sight-threatening complication of Thyroid Eye Disease (TED). This study aims to identify the risk and predictive factors for DON in a multi-ethnic TED cohort.

Methods: Retrospective, cohort study of consecutive TED patients attending a multidisciplinary service over an 11-year period. Consecutive patients aged over 18 years old with a minimum of 6 months follow-up post-diagnosis of TED were included. We compared those patients with DON and those without (no-DON) to determine which factors were more prevalent in patients with DON.

Results: There were 26 and 516 consecutive patients with DON and no-DON. The DON prevalence in the cohort was 5.0%. The DON group had a Mean Age at TED Diagnosis (MATD) of 57.8 vs. 46.1 years in the no-DON group. The mean presenting CAS, TRAb and Gorman Diplopia Score (GDS) were significantly higher 3.73 ± 1.80, 2.76 ± 1.05 and 11.31 ± 11.90 vs. 0.54 ± 0.80, 0.48 ± 0.90 and 6.95 ± 9.22 in the DON compared to the no-DON group respectively (p = 0.00, p = 0.00 and p = 0.04). On multivariable regression, we found the following risk factors for developing DON (Odds Ratios): MATD ≥ 53 years (5.2 p = 0.00), presenting CAS ≥ 4 (P = 0.00), presenting GDS ≥ 3 (7.5 p = 0.00), diabetes (5.7 p = 0.00), and baseline TRAb ≥ 5.0 IU/L (2.9 p = 0.04).

Conclusion: Patients with diabetes, increased MATD, and high presenting CAS, GDS, and TRAb are at increased risk of developing DON in our cohort. Clinicians should be especially vigilant of the risk of sight-threatening complications in TED patients with more than one of the above risk factors.