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.