Epidemiological Study Of Myasthenia Gravis Research Articles

Impact of COVID-19 pandemic on the incidence and severity of myasthenia gravis in Korea: using National Health Insurance Service database

Impact of COVID-19 pandemic on the incidence and severity of myasthenia gravis in Korea: using National Health Insurance Service database

Epidemiological Study of Myasthenia Gravis in Patients Referring to Farshchian Hospital in Hamadan

Background: Myasthenia gravis (MG) is an autoimmune disease that leads to fatigue and weakness after voluntary activities. If early diagnosed, MG can be treated, and a person’s performance and quality of life can be greatly improved as well. Materials and Methods: The study population of the present cross-sectional study included 80 patients with MG referring to Sina (Farshchian) hospital in Hamadan, Iran. The inclusion criterion included complete medical files. Finally, the variables were investigated using the chi-square test and two-sample t test by SPSS, version 16. Results: The mean (standard deviation) of the patients’ age was 45.6 ± 15.8 years and most patients (55.5%) were females and 72.5% of them were married. In addition, weakness, lethargy, and premature fatigue were the most common symptoms (47.5%) in patients while unsteady gait was the lowest prevalent symptom (11.3%). There was no significant relationship between gender and the incidence of symptoms in patients (P>0.05). However, a significant relationship was found between patients’ age with the shortness of breath and unsteady gait (P<0.05). Eventually, most women, especially married and elderly ones, contracted the disease. Conclusion: In general, there is a proper treatment for MG considering its early diagnosis. Accordingly, it is recommended that the level of awareness should be increased about the disease and provide appropriate medical and therapeutic facilities in this regard.

Hospital and healthcare insurance system record-based epidemiological study of myasthenia gravis in southern and northern China.

This is the first cross-region epidemiological study of myasthenia gravis (MG) in China. We estimated the incidence, prevalence, and medical costs of MG in southern China and explored the differences between the southern and northern Chinese populations. We collected and analyzed records from 20 hospitals in the southern city, Guangzhou, 13 hospitals in the northern city, Harbin, and two healthcare insurance systems: job based and residence based in Guangzhou during 2000-2017. (1) The estimated annual incidence of MG was 1.55-3.66 per 100,000, and the estimated prevalence of MG was 2.19-11.07 per 100,000 in southern China based on insurance records. (2) The proportion of hospitalized MG patients in the south-based hospital records was three times as high as that in the north-based hospital records. (3) Female MG prevalence was significantly higher than male MG prevalence in Guangzhou, while the similar gender difference in Harbin was not statistically significant due to higher variation in earlier years. (4) The average expense was $35-42 for each outpatient service and $2526-2673 for each hospitalization expense in the south. (5) Contrary to the increase of insurance-based estimate of MG prevalence, the proportion of hospitalized MG patients did not increase over the years, suggesting rising awareness and utilization of health insurance. The southern MG population had a significantly higher prevalence and a lower response threshold to medication than the northern MG population. These results are calling for further investigations on the genetic, cultural, and environmental variations of the Chinese MG populations between north and south.

A nationwide epidemiological study of myasthenia gravis in Latvia.

Myasthenia gravis (MG) is an autoimmune disorder characterized by fatigable muscle weakness due to antibody-mediated impairment of neuromuscular transmission. The aim of this study was to investigate the incidence and prevalence of MG in Latvia, and to characterize this population by well-established clinical parameters such as age at onset, presence of associated antibodies and thymus pathology. All prevalent cases on 1 January 2015 and cases of patients newly presenting with MG symptoms from 1 January 2010 to 31 December 2014 were selected from the database of the Neuromuscular Disease Clinic of Pauls Stradins Clinical University Hospital and Children's Clinical University Hospital. Crude rates were calculated based on population data. These were directly age-standardized to the European and World Health Organization world standard populations. The analysis of clinical characteristics was carried out in a cohort of patients who had undergone a complete set of electrophysiological, serological and radiological investigations (n=153; 68%). During the study period 99 incident and 226 prevalent cases were identified. The total crude MG incidence was 9.7 per million person-years. The prevalence of MG on 1 January 2015 was 113.8 per million. 54.2% of patients tested positive for acetylcholine receptor antibodies, 7.8% for muscle specific kinase antibodies and 1.3% for lipoprotein related protein 4 antibodies. This is the first study of MG in Latvia and the second population-based study of MG in Eastern Europe. Our epidemiological results are similar to those in some other European and Northern American countries, and show high prevalence and increasing incidence of late-onset MG.

Incidence and Prevalence of Myasthenia Gravis in Korea: A Population-Based Study Using the National Health Insurance Claims Database

Background and PurposeThere have been a few national population-based epidemiological studies of myasthenia gravis (MG) with wide variation of incidence and prevalence rates worldwide. Herein we report the first nationwide population-based epidemiological study of MG in Korea.MethodsWe attempted to estimate the incidence and prevalence rates of MG using the Korean National Health Insurance claims database for 2010 to 2013. Cases with MG were defined as those having claim records with a principal diagnosis of MG and the prescription of acetylcholinesterase inhibitors or immunosuppressive agents including corticosteroids and azathioprine within 2 years after the diagnosis. The year 2010 was set as a washout period, such that patients were defined as incident cases if their first records of MG were observed in 2011.ResultsIn 2011 there were 1,236 incident cases, and the standardized incidence rate was 2.44 per 100,000 person-years. The standardized prevalence rates were 9.67 and 10.66 per 100,000 persons in 2010 and 2011, respectively. The incidence and prevalence rates peaked in the elderly population aged 60 to 69 years for both sexes.ConclusionsThis is one of the largest national population-based epidemiological studies of MG, and it has confirmed the high incidence and prevalence rates of MG in the elderly population of South Korea.

The Epidemiology of Myasthenia Gravis in Korea.

PurposeAn epidemiological study of myasthenia gravis (MG) has not been performed in Korea. The purpose of this study was to estimate the prevalence and incidence of MG in Korea.Materials and MethodsHealth Insurance Review and Assessment (HIRA) data from 2010 to 2014 were searched for MG codes as defined by the International Classification of Diseases, 10th revision. After identifying MG cases, we estimated the prevalence and annual incidence of MG based on the HIRA database and Korean population data.ResultsDuring the study period, 10138 MG cases were identified. The prevalence of MG was 10.42 cases per 100000 people in 2010 and this increased every year to 12.99 cases per 100000 people in 2014. The average incidence of MG between 2011 and 2014 was 0.69 cases per 100000 person-years. The prevalence and incidence were higher in the older (≥50 years) age group than in the younger (<50 years) age group [prevalence: 9.26 vs. 19.24 per 100000, relative risk 2.077, 95% confidence interval (CI) 1.976-2.183, p<0.001; incidence: 0.47 vs. 1.18 per 100000, relative risk 2.490, 95% CI 2.006-3.091, p<0.001].ConclusionThis study was the first nationwide population-based epidemiological study of MG in Korea. The prevalence and incidence of MG were consistent with those of previous studies. We found an increase in the prevalence of MG and a predominance of elderly MG patients.

01 What is seronegative MG? analysis of the Northern Irish MG population

BackgroundSeronegative MG (SNMG) is the proportion of autoimmune MG without detectable pathogenic antibodies to AChR or MuSK on radio-immunoprecipitation or recently developed cell-based assays. The effect of the application of...

Nationwide Population-Based Epidemiological Study of Myasthenia Gravis in Taiwan

Background: The purpose of this study is to investigate the epidemiology and medical expenses of myasthenia gravis (MG) in Taiwan. Methods: Cases of MG were identified from the National Health Insurance Research Database with corresponding codes of the International Classification of Diseases, ninth revision (ICD-9), from January 2000 to December 2007. Age- and sex-specific incidences were estimated by dividing the incidence number by population data obtained from the Department of Statistics, Ministry of the Interior. Results: During the study period, 5,211 cases were identified. The incidence ratio of males to females was 0.68. The average annual incidence rate was 2.1/100,000. MG occurred in all age groups with a higher incidence in older individuals and the lowest incidence in the 10- to 14-year-olds for both sexes. Among the 5,211 cases, 615 (12%) had a neoplasm of the thymus. The prevalence increased steadily during the study period from 8.4/100,000 in 2000 to 14.0/ 100,000 in 2007. Conclusions: This is the first population-based epidemiological study of MG in Taiwan. The incidence rate and prevalence were higher than in most published studies, especially in old age groups.

Associated autoimmune diseases in myasthenia gravis. A population-based study.

During a comprehensive epidemiological study of myasthenia gravis (MG) in Western Denmark 1975-1989, we analyzed the occurrence, clinical characteristics and prognosis of associated autoimmune diseases (AAD) in MG patients. AAD were found in 20 of 212 incident cases (9%) and in 30 of 220 prevalent cases (14%). The most common diseases were: thyroid disorders and rheumatic arthritis. Clinically, it was not possible to identify a subgroup of MG patients with a higher risk of AAD. In most MG patients the AAD occurred before thymectomy. The severity of the AAD was not influenced by thymectomy. The remission rate was lower in MG patients with AAD than in MG patients without AAD suggesting that the autoimmune response in MG patients with AAD is more severe.

Epidemiological and clinical characteristics of myasthenia gravis in Belgrade, Yugoslavia (1983-1992).

This is the first epidemiological study of myasthenia gravis (MG) in the area of Belgrade. During the survey period (1983 1992), 124 incidental cases of MG were observed, producing an average annual incidence rate of 7.1 per million population (women, 8.3; men, 5.8). Age and sex specific incidence rates for females demonstrated a bimodal pattern, with the first peak in the age group between 20 and 40, and the second peak in the age group 70-80. The age-specific rates for males showed unimodal pattern, reaching a maximum in the age group between 60 and 80. There was a tendency of more frequent disease appearance in the urban as opposed to the suburban districts. On the prevalence day, December 31, 1992, the point prevalence rate was 121.5 per million (women, 142.5; men, 98.8). Only for incidental cases, the point prevalence rate was 77.1 (women, 83.2; men, 70.4). The average annual mortality rate was 0.47 per million (females, 0.52; males, 0.42), while cumulative lethality was 5.6 (women, 5.6; men, 5.7). Most frequently initial symptoms were ocular, occurring in 58% patients. Through the period of investigation ocular symptoms were generalized in 68%, most frequently in the first 2 years (62.5%). Thymoma was confirmed in 11.3% of patients. In this group there was equal presence of both sexes, older median age at onset, and more severe clinical course of MG. Associated autoimmune disease was found in 17 out of 124 incidental cases (13.7%). The most common were thyroid diseases (7.3%). Family history of MG was recorded in 2 cases belonging to 1 family (1.6%).

Incidence and Prevalence of Myasthenia gravis in the County of the Coast and Gorski kotar, Croatia, 1976 through 19961

For the period 1976 through 1996, we carried out an incidence and prevalence study of myasthenia gravis in the County of the Coast and Gorski kotar, Croatia. This was the first epidemiological study of myasthenia gravis in Croatia. A total of 43 incident cases were identified. Overall the average crude annual incidence rate was 6.52 per 1,000,000 person-years; 5.59 per 1,000,000 person-years for men and 7.41 per 1,000,000 person-years for women. The incidence rate was 6.30 (95% confidence intervals 4.56–8.51), age-adjusted to the European population and 5.17 (95% confidence intervals 3.74–6.98), age-adjusted to the world population. On 31 December 1996, there were 32 prevalent cases. The crude prevalence was 99 per 1,000,000 population (95% confidence intervals 67.7–139.6). The prevalence adjusted to the European and world populations was 101.9 (95% confidence intervals 69.7–143.7) and 75.9 (95% confidence intervals 51.9–107) per 1,000,000 population, respectively. Our incidence findings are similar to those reported in North-East Italy but lower than those in the United States. Our prevalence findings were generally higher than those in Northern European Countries but lower than those in the United States. Standardization of rates to the European or world population could facilitate comparison between different populations.

Mortality and survival in myasthenia gravis: a Danish population based study

OBJECTIVESTo study mortality and survival of patients with myasthenia gravis.METHODS290 patients with myasthenia gravis were studied, including 212 incident cases identified during a comprehensive epidemiological study of myasthenia gravis in...

Epidemiological study of myasthenia gravis in the province of Reggio Emilia, Italy.

We carried out a retrospective incidence, prevalence and mortality survey of myasthenia gravis in the province of Reggio Emilia in Northern Italy. Based on 49 patients, the mean incidence per year for the period 1980 through 1994 was 7.8 per 1,000,000. On 31 December 1994 the prevalence rate was 117.5 per 1,000,000 for all patients, either active or recovered (50 cases in a population of 427,493) and 103.4 per 1,000,000 for the active disease. In the 15-year period 1980-1994 the average mortality rate was 1.0 per 1,000,000 per year. The average age at onset was 44.6 +/- 21.0, and the average age at the time of prevalence determination was 51.1 +/- 19.6 for the active disease. At the time of diagnosis, 21 patients (36.8%) were classed in group I according to Osserman's criteria, 31 in group II (54.4%), (19 in group II-A and 12 in group II-B), and the other 5 (8.8%) in group III. Of all the prevalence cases, 6 (12%) were in remission without therapy and 6 with therapy, while most of the others 16 (32%) were classed in group I, 15 (30%) in group II, and 1 (2%) in group III. Thymectomy was performed in 20 patients (35.1%), 12 (21%) had thymoma (malignant in 4 cases), 6 had thymic hyperplasia while in two patients thymic histology was normal. The relation the grade of Osserman's scale at the time of incidence and the presence of thymoma were significant. Higher grades of Osserman's scale were associated were malignant thymoma. Furthermore the relationship between thymectomy and the grade of Osserman's scale at the date of prevalence was significant for the presence of lower grades of Osserman's scale in the patients submitted to thymectomy.

Epidemiological study of myasthenia gravis in the province of Ferrara, Italy.

The only prevalence rate of myasthenia gravis (MG) so far estimated in Italy by an epidemiological study carried out in Pavia, North Italy, indicates a prevalence quite similar to that observed in other countries. The purpose of the survey was to verify the frequency of the disease in a geographically well-defined and previously surveyed community. On the basis of 39 cases, on 31 December 1987 the prevalence per million was 105.3 (102.3 if standardized for the Italian population). This is the highest prevalence figure yet found, indicating a value similar to that established in Northern Europe. According to Kurtzke this high prevalence rate reflects the high standard of the local public health service, which permitted a more intensive search for affected subjects.

Epidemiology of myasthenia gravis in Finland

The epidemiological results of an investigation of myasthenia gravis in Finland which started in the autumn of 1963 are presented. Most of the material was collected from the years 1954–1966. The total number of cases ascertained was 183 of which 4 were cases of neonatal myasthenia in complete remission. For 1956–1965 the annual incidence of myasthenia gravis in the whole of Finland was 2.27 per million and in the central hospital district of Helsinki 3.52 per million. The age distribution of all the patients included at the onset of symptoms is presented as well as the duration of the disease up to the moment of diagnosis. The prevalence of myasthenia gravis in the whole of Finland on 1 January 1964 was 102 cases (plus 3 cases of neonatal myasthenia in complete remission), of which 77 were women and 25 men. On 1 January 1968 the corresponding prevalence figure was 117 (plus 3 cases of neonatal myasthenia), 85 women and 32 men, i.e. a frequency of 25 per million. The corresponding prevalence in the Helsinki central hospital district was 42 per million. The number of established cases in the central hospital districts in the eastern region of the country was relatively much lower than in the southern and western central hospital districts. Comparisons are drawn as to the distribution of the prevalence cases with regard to place of birth, place of residence at the onset of symptoms and the place of residence at the time of prevalence. No significant changes were observed. The possible significance in the differences of regional frequency between the hospital districts is discussed. It is estimated that the actual prevalence of myasthenia gravis in Finland is 50–75 per million inhabitants. The annual mortality for the years 1957–1966 of those cases of the series in which the diagnosis was confirmed was 0.74 per million. This figure is probably lower than the actual rate. If the number of other cases suffering from myasthenia gravis according to their death certificates is also taken into account, the corresponding annual mortality figure is 0.87 per million. Of the 48 deaths in patients belonging to the series of confirmed cases, myasthenia gravis was entered on the death certificate as the primary cause of death in 35 of the cases and as a contributory cause of death in 4 of them, but was omitted entirely in 9 of them. Of all deaths, 58.5% took place during the first 3 years of the illness. The results of this epidemiological study of myasthenia gravis carried out in Finland are compared with those of similar investigations carried out in England, USA, Norway and Iceland as well as with results of less comprehensive studies reported from Canada, New Zealand, Japan, Malta and Africa. The results concerning Finland are not inconsistent with those obtained elsewhere. The causes of variations in frequency are discussed.