Risk of incident autoimmune diseases in patients with thymectomy

Abstract

Objectives: The data concerning the association between Tx and ADs remain unclear and are scarce. This study was undertaken to investigate whether people with Tx are more likely to develop ADs, compared to those without Tx. Methods: Individuals who received Tx between 2002 and 2015 were identified and matched on age and sex with individuals without Tx. We performed multivariate and stratified analysis using the Kaplan-Meier method and Cox proportional hazards models in order to estimate the association between Tx and the risk of developing ADs. Results: A total of 2550 thymectomized (Txd) patients and 24,664.941 non-Txd comparison subjects were selected from NHIRD. Tx-MG (myasthenia gravis) as compared with general population (nonTx-nonMG), adjusted hazard ratio (aHR) were higher for incident Addison disease (aHR = 10.40, 95% CI 1.01-107), autoimmune hemolytic anemia (aHR = 21.54, 95% CI 2.06-14.8), Hashmoto thyroiditis (aHR = 5.52, 95% CI 1.34-34.7), ankylosing spondylitis (aHR = 2.73, 95% CI 1.09-6.84), rheumatoid arthritis (aHR = 5.25, 95% CI 1.79-15.47), primary Sjogren syndrome (pSS) (aHR = 3.77, 95% CI 1.30-11.0), and systemic lupus erythemtoasus (aHR = 10.40). Tx-nonMG as compared with general population, aHR were higher for incident autoimmune hemolytic anemia (aHR = 25.50), Hashmoto thyroiditis (aHR = 6.75) and systemic lupus erythematosus (SLE) (aHR = 13.38). NonTx-MG as compared with general population, aHR were higher for incident Hashmoto thyroiditis (aHR = 6.57), pSS (aHR = 4.50), SLE (aHR = 17.29), and systemic vasculitis (aHR = 25.86). Interpretation: In conclusion, based on a retrospective cohort study throughout Taiwan, patients with Tx have a higher risk of new onset ADs than patients without Tx.

Clinical characteristics of myasthenia gravis (MG) patients developing other autoimmune diseases after thymectomy from one single center cohort

“…14 Furthermore, thymectomy in patients without MG may also increase the risk of ADs, and the overall incidence rate of ADs has been reported to be 2.68 times higher in thymectomy patients than those who did not undergo thymectomy. 17 In this study, the incidence rate of patients developing a new AD after thymectomy was 4.3%, which was higher than the incidence rate of new onset ADs in patients without thymectomy after the diagnosis of MG (1.98%), and also higher than MG patients after thymectomy (3.3%) in the Taiwanese cohort. 17 The proportions of different types after surgery changed.…”

“…A total of 19 patients (4.3%) developed a new AD after thymectomy (Figure 2). The frequency was higher than the incidence rate of new onset ADs in patients in whom thymectomy was not performed after the diagnosis of MG (1.73%), and even higher than in MG patients in whom thymectomy was performed (3.3%) in a Taiwanese cohort study 17 . The median postoperative follow‐up period at the diagnosis of the new AD was 48 months (range, 6–108 months).…”

“…The frequency was higher than the incidence rate of new onset ADs in patients in whom thymectomy was not performed after the diagnosis of MG (1.73%), and even higher than in MG patients in whom thymectomy was performed (3.3%) in a Taiwanese cohort study. 17 The median postoperative follow‐up period at the diagnosis of the new AD was 48 months (range, 6–108 months). In this study, the most common type of new onset ADs after thymectomy was Hashimoto's thyroiditis (47.4%, 9/19), and the second was RA (31.6%, 6/19).…”

“…One cohort study from Taiwan revealed that thymectomy in patients with MG increased the risk of autoimmune rheumatic diseases 14 . Furthermore, thymectomy in patients without MG may also increase the risk of ADs, and the overall incidence rate of ADs has been reported to be 2.68 times higher in thymectomy patients than those who did not undergo thymectomy 17 …”

Comorbidities worsen the prognosis of generalized myasthenia gravis post-thymectomy

“…Thymoma-induced MG, on the other hand, is associated with hematological ADs and autoimmune myocarditis [1]. Interestingly, a recent Taiwanese study concluded that patients with or without MG who underwent thymectomy had a higher risk of new onset AD [19]. Currently, non-autoimmune comorbidities, such as type 2 diabetes, hypertension, and coronary diseases, are common in MG due to increased life expectancy and are understandably more common in patients with late-onset MG [20].…”