Jiann-Horng Yeh

Low frequency of MuSK antibody in generalized seronegative myasthenia gravis among Chinese

Approximately 15% of 1patients with generalized myasthenia gravis (MG) lack detectable circulating antibodies to the acetylcholine receptor (AChRAb), referred to as seronegative MG (SNMG). During the last 3 years, antibodies against muscle-specific tyrosine kinase (MuSKAb) were found in about 40 to 70% of patients with SNMG.1–5⇓⇓⇓⇓ We report the first MuSKAb survey among Chinese patients with SNMG and compare the features of MuSKAb-positive patients with those of Caucasian patients. During last 10 years, we collected data from 774 myasthenic patients (389 with the ocular type and 385 generalized type) at the Shin Kong Wu Ho-Su Memorial Hospital. Among patients with generalized MG, 38 (9.8%) were seronegative for AChRAb. We enrolled 26 of these patients, who had been monitored regularly; 20 were women and 6 were men (table). Twenty patients were in Osserman stage IIa, four were in IIb, and two patients were in stage III. Limb weakness was the most common …

Clinical features of myasthenia gravis patients with autoimmune thyroid disease in Taiwan

The aim of this study was to analyze the prevalence and clinical features of myasthenia gravis (MG) patients with and without autoimmune thyroid disease (ATD).

Increased risk of osteoporosis in patients with myasthenia gravis A population-based cohort study

Objective: To determine the risk of osteoporosis in patients with myasthenia gravis (MG) in a large cohort representing 99% of the population of Taiwan. Methods: Data from the Taiwan National Health Insurance Research Database were used to conduct retrospective cohort analyses. The study cohort consisted of 2,073 patients with MG who were 3-fold frequency-matched by age and sex and assigned the same index year as a comparison cohort without MG. Cox proportional hazard regression analysis was conducted to estimate the risk of osteoporosis. Results: The MG cohort had a 1.96-fold increased risk of developing osteoporosis compared with the comparison cohort (hazard ratio [HR] = 1.96, 95% confidence interval [CI] = 1.57–2.44). Patients with MG older than 30 years developed an increased risk of osteoporosis, with the highest risk in the age group from 30 to 44 years, compared with the control cohort. Corticosteroid-naïve patients with MG had a 1.52-fold increased risk of developing osteoporosis (HR = 1.52, 95% CI = 1.11–2.08), and the corticosteroid-treated cohort had a 2.37-fold increased risk of developing osteoporosis (HR = 2.37, 95% CI = 1.82–3.07). Conclusion: This population-based retrospective cohort study provides evidence that MG is associated with a high risk of osteoporosis regardless of corticosteroid use.

Hashimoto's Thyroiditis, Risk of Coronary Heart Disease, and L-Thyroxine Treatment: A Nationwide Cohort Study

OBJECTIVE Our objective was to investigate the risk of coronary heart disease (CHD) in patients with Hashimotos thyroiditis (HT). METHODS The Taiwan National Health Insurance Research Database was used to conduct a retrospective cohort analysis. The cohort study consisted of 1165 newly diagnosed HT patients and 4660 matched controls (non-HT patients) from 2000 to 2010. The median follow-up time was 5.46 years. The risk of developing CHD for HT patients was measured using the Cox proportional hazards model. RESULTS The risk of developing CHD in HT patients was increased compared with the non-HT controls, with an adjusted hazard ratio (HR) of 1.44 (95% confidence interval [CI] = 1.05-1.99). The risk was significant in women but not in men, and restricted to subjects younger than 49 years. HT remained an independent risk factor after adjusting for comorbidities; however, combining with hypertension or hyperlipidemia further increased the risk of CHD (adjusted HR = 2.06, 95% CI = 1.46-2.92; and adjusted HR = 1.83, 95% CI = 1.31-2.55, respectively). Furthermore, HT without T4 treatment and HT with treatment for less than 1 year were associated with higher risk of CHD (adjusted HR = 1.55, 95% CI = 0.98-2.46; and adjusted HR = 2.42, 95% CI = 1.43-3.97, respectively). The risk of CHD decreased after treatment with T4 for more than 1 year and did not differ from the non-HT cohort (adjusted HR = 0.84, 95% CI = 0.0.47-1.52). CONCLUSION Patients with HT, are at higher risk of developing CHD compared with the general population. Treatment with T4 reduces the risk of CHD.

Higher Risk of Myasthenia Gravis in Patients With Thyroid and Allergic Diseases: A National Population-Based Study

AbstractThe aim of this study was to determine the risk of myasthenia gravis (MG) in patients with allergic or autoimmune thyroid disease in a large cohort representing 99% of the population in Taiwan.Data from the Taiwan National Health Insurance Database were used to conduct retrospective analyses. The study comprised 1689 adult patients with MG who were 4-fold frequency matched to those without MG by sex, age, and assigned the same index year. Multivariate logistic regression models were used to calculate the odds ratios and 95% confidence intervals for the association between allergic or autoimmune thyroid disease and MG.An increased subsequent risk of MG was observed in the patients with allergic conjunctivitis (AC), allergic rhinitis, Hashimoto thyroiditis, and Graves disease. The adjusted odds ratios (aORs) were 1.93 (1.71–2.18), 1.26 (1.09–1.45), 2.87 (1.18–6.97), and 3.97 (2.71–5.83), respectively. The aORs increased from 1.63 (1.43–1.85) in a patient with only 1 allergic or autoimmune thyroid disease to 2.09 (1.75–2.49) in a patient with 2 thyroid or allergic diseases to 2.82 (2.19–3.64) in a patient with ≥3 thyroid or allergic diseases. MG was associated with the cumulative effect of concurrent allergic and autoimmune thyroid disease with combined AC and Hashimoto thyroiditis representing the highest risk (aOR = 15.62 [2.88–87.71]).This population-based case-control study demonstrates the association between allergic or autoimmune thyroid disease and the risk of MG. The highest risk of subsequent MG was associated with combined AC and Hashimoto thyroiditis.

Effects of double filtration plasmapheresis on nocturnal respiratory function in myasthenic patients.

Assessment of respiratory function using combined oximetry-cutaneous capnography has never been evaluated in patients with myasthenia gravis (MG). We investigated the effects of double filtration plasmapheresis (DFPP) on respiratory status in 18 MG patients. Results of combined oximetry and transcutaneous capnography, MG scores, and acetylcholine receptor antibody titers before and after DFPP treatment were compared. The respiratory monitoring was performed at three time periods (morning, afternoon, and sleep). Mean MG score was markedly lower after DFPP treatment (5.7) than before treatment (7.9). Before DFPP, the minimum pulse oximetric saturation (SpO2 ) level obtained during the night session was significantly lower (P = 0.0513 and P = 0.0199) than the levels obtained during the two daytime sessions. A similar phenomenon was noted for maximum transcutaneous carbon dioxide tension (PtcCO2 ). After DFPP treatment, the maximum and mean PtcCO2 levels were significantly higher (P = 0.0056) in the morning than in the afternoon. Of all the respiratory function parameters measured, only minimum SpO2 levels obtained during morning sessions before DFP treatment differed significantly from those obtained after DFPP treatment (P = 0.0322). Overall, however, minimum SpO2 levels as well as mean and maximum PtcCO2 levels improved significantly during sleep after DFPP. In conclusion, we found that respiratory function abnormalities were common in myasthenic patients without clinical respiratory symptoms. DFPP treatment resulted in minimal improvement of respiratory parameters.

Excessive risk of cancer and in particular lymphoid malignancy in myasthenia gravis patients: A population-based cohort study

The exact relationship between myasthenia gravis (MG) and extrathymic malignancies has not been established thus far. Occasional cases of MG have been reported in association with lymphoma or other lymphoproliferative disorders. To determine the risk of extrathymic malignancy with particular attention on lymphoid malignancy for MG patients in a large cohort representing 99% of the Taiwan population, claims data from the Taiwan National Health Insurance Database were used to conduct retrospective cohort analyses. The study cohort comprised 3671 MG patients who were 10-fold frequency matched by age and sex, and assigned the same index year without MG. Cox proportional hazard regression analysis was conducted to estimate the risk of cancer. The MG cohort had a 1.74-fold increased risk of developing cancer compared to the comparison cohort (HR=1.74, 95% CI=1.47-2.05). After adjusting for confounders and relative to the cohort, patients with MG had a 2.27-fold increased risk of developing lymphoid malignancies (HR=2.27, 95% CI=1.06-4.88) and a 118.47-fold increased risk of thymus cancer (HR=118.47, 95%=42.57-329.71). This population based retrospective case-control study confirms and extends previous observations on the association between MG and lymphoid malignancies.

Risk of diabetes mellitus among patients with myasthenia gravis

To determine the risk of diabetes mellitus (DM) in patients with myasthenia gravis (MG) in a large cohort representing 99% of the Taiwan population.