A comprehensive score to diagnose Hashimoto's thyroiditis: a proposal

The heterogeneity of diagnostic criteria of Hashimoto's thyroiditis leads to overdiagnosis and prevents strong conclusions from being drawn in clinical studies. The aim of this study is to propose a comprehensive scoring system. A case-control study compared a set of presurgical features of patients with lymphocytic infiltration of the thyroid (Hashimoto's thyroiditis) and controls, in order to design a multi-criteria scoring system. Given a dichotomous outcome (lymphocytic infiltration of the thyroid), a set of covariates was analyzed in 180 patients after total thyroidectomy. A different validation cohort of 1,171 patients was reviewed and classified according to the score. Variables associated with the diagnosis of Hashimoto's thyroiditis were first assessed by univariate analysis. Analysis showed that TPOAb (area under the ROC curve (AUC), 0.67; 95 % CI 0.57-0.77) and TgAb (0.63; 95 % CI 0.54-0.74) were univariate predictors of the diagnosis of HT, which is largely recognized. Combined covariates were then tested using stepwise logistic regression analysis. The final regression model included TPOAb, TgAb, and thyroid vascularity (AUC 0.72; 95 % CI 0.62-0.81). A scoring system was developed, which has a sensitivity of 45.5 % and a specificity of 89.0 %, with a cutoff of 1.7. The likelihood of incident hypothyroidism was higher (OR 2.30; p = 0.004) in the positive (≥1.7) score group. A scoring system has a better performance than any single predictor and is able to identify the subgroup of individuals at higher risk to develop subsequent hypothyroidism.