A 20-year study of autoimmune polyendocrine syndrome type II and III in Taiwan.

Purpose: Autoimmune polyendocrine syndrome (APS) is a rare immune-endocrinopathy characterized by the failure of at least two endocrine organs. Clinical characteristics have mainly been described in the Western population. This study comprehensively analyzed the demographic and clinical manifestations of APS II and APS III in Taiwan. Methods: Patients aged ≥20 years with a diagnosis of APS II or APS III in ten hospitals between 2001 and 2021 were enrolled. The clinical and serological characteristics of the patients were retrospectively reviewed. Results: Among the 187 enrolled patients (45 men and 142 women); only seven (3.7%) had APS II, while the others had APS III. Fifty-five patients developed hyperthyroidism and 44 patients developed hypothyroidism. Men were diagnosed with APS at a younger age than women (16.8 vs 27.8 years old, P = 0.007). Most patients were initially diagnosed with type 1 diabetes mellitus. There was a positive correlation between age at diagnosis and the likelihood of developing thyroid dysfunction. For every year older patients were diagnosed with APS III, the risk of developing hyperthyroidism increased by 3.6% (P = 0.002), and the risk of developing hypothyroidism increased by 3.7% (P = 0.035). Positive anti-parietal cell antibodies (APCA) were associated with a higher risk of anemia in patients with APS III (P < 0.001). Conclusion: This study provides the most comprehensive analysis of APS II and APS III in Asia. The percentage of patients with APS II was significantly lower than in the Western population. A second autoimmune endocrinopathy may develop several years after the first one. APCA examination is valuable when evaluating anemia in patients with APS.