Thyrotropin Receptor Autoantibodies Are Independent Risk Factors for Graves’ Ophthalmopathy and Help to Predict Severity and Outcome of the Disease

Abstract

The objective of this study was to examine whether TSH-receptor antibody [TSH binding inhibitory antibodies (TBII)] levels are associated with the severity of Graves' ophthalmopathy (GO) over the entire course of the disease. A total of 159 patients with GO were followed for 12-24 months. One year after the first symptoms of GO, all patients were classified into mild or severe GO according to their clinical manifestations. TBII were measured every 3 months after onset of GO. Receiver operating characteristic plot analysis was performed to assess the power to discriminate both patient groups by TBII (specificity >90%). TBII levels and prevalence at each time point during follow-up were significantly higher in patients with a severe course of GO compared with patients with a mild course of GO. Prognostic statements on the course of the disease were possible for about half of the GO patients at all time points (except the first). If at first presentation and at consecutive time points TBII levels were less than 5.7, 2.6, 1.5, 1.5, 1.5, and 1.5 IU/liter, the patients had a 2.3- to 15.6-fold higher chance of a mild course. If 5-8 months after GO onset and at consecutive time points TBII levels were above 8.8, 5.1, 4.8, 2.8, and 2.8 IU/liter, the patients had a 8.7- to 31.1-fold higher risk of a severe course. This relationship of TBII to the severity was independent from age and smoking. Follow-up measurements of TBII allow, in half of the patients, assessment of the prognosis of GO and, therefore, could be of additional help for the disease management.