Pattern of Thyroid Autoimmunity in Chinese Patients With Pernicious Anemia

Abstract

BackgroundAutoimmune thyroid disease (AITD) often coexists with pernicious anemia (PA) among whites. The study aimed to determine thyroid autoimmunity in Chinese patients with PA MethodsFrom the data of a hospital-based longitudinal study of Chinese PA patients (1994–2007), those with complete information of antibodies to thyroid peroxidase (TPO), thyroglobulin (Tg), and gastric parietal cell; serum thyroid-stimulating hormone and free thyroxine; gastric mucosal histology; and family history of AITD were analyzed. ResultsAmong 126 Chinese PA patients, 44% had TPO/Tg antibodies and 13.5% AITD. TPO/Tg antibodies occurred in 33% (16 of 49) of male and 52% (40 of 77) of female patients (P=0.034). Graves disease (8 patients) tended to antedate PA and was associated with no or low titers of TPO/Tg antibodies. Primary hypothyroidism (9 patients) developed during follow-up and was associated with high TPO/Tg antibody titers. The TPO/Tg antibodies did not affect the clinical course of PA but was associated with an enhanced risk of developing AITD and vitiligo. Overall, AITD (before and after PA) occurred in 23% (13 of 56) and 5.7% (4 of 70) of PA patients with and without antibodies (P=004). During follow-up (mean duration of 75.24±46.39 months), 10 patients developed AITD—7 new onset of hypothyroidism and 3 progression/relapse of prior AITD. Logistic regression analysis of presenting features of PA revealed 2 independent factors for AITD development during follow-up—presence of thyroid antibodies (odds ratio 20.2, 95% confidence interval 1.8–223) and history of prior AITD (odds ratio 39.8, 95% confidence interval 2.3–679). ConclusionIt is recommended to screen thyroid antibodies and monitor thyroid function during follow-up.