Predictive score for the development or progression of Graves' orbitopathy in patients with newly diagnosed Graves' hyperthyroidism

Objective: To construct a predictive score for the development or progression of Graves' orbitopathy (GO) in Graves' hyperthyroidism (GH). Design: Prospective observational study in patients with newly diagnosed GH, treated with antithyroid drugs (ATD) for 18 months at ten participating centers from EUGOGO in 8 European countries. Methods: 348 patients were included with untreated GH but without obvious GO. Mixed effects logistic regression was used to determine the best predictors. A predictive score (called PREDIGO) was constructed. Results: GO occurred in 15% (mild in 13% and moderate to severe in 2%), predominantly at 6-12 months after start of ATD. Independent baseline determinants for the development of GO were clinical activity score (assigned 5 points if score > 0), TSH-binding inhibitory immunoglobulins (2 points if TBII 2-10 U/L, 5 points if TBII > 10 U/L), duration of hyperthyroid symptoms (1 point if 1-4 months, 3 points if >4 months) and smoking (2 points if current smoker). Based on the odds ratio of each of these four determinants, a quantitative predictive score (called PREDIGO) was constructed ranging from 0 to 15 with higher scores denoting higher risk; positive and negative predictive values were 0.28 (95% CI 0.20-0.37) and 0.91 (95% CI 0.87-0.94) respectively. Conclusions: In patients without GO at diagnosis, 15% will develop GO (13% mild, 2% moderate to severe) during subsequent treatment with ATD for 18 months. A predictive score called PREDIGO composed of four baseline determinants was better in predicting those patients who will not develop obvious GO than who will.