Database of Wards for Patients with Muscular Dystrophy in Japan

Twenty-seven hospitals in Japan specialize in treatment of muscular dystrophy patients, including inpatient care, of which 26 belong to the National Hospital Organization, and the other is the National Center of Neurology and Psychiatry. Since 1999, Japanese muscular dystrophy research groups investigating nervous and mental disorder have been developing a database of cases treated at these 27 institutions. In that regard, we conducted a survey of inpatients with muscular dystrophy and other neuromuscular disorders based on data collected by the National Hospital Organization and National Center of Neurology and Psychiatry. Herein, we examined data obtained between 1999 and 2010 in order to evaluate the medical condition of inpatients with muscular dystrophy in Japan.


Introduction
Twenty-seven hospitals in Japan specialize in treatment of muscular dystrophy patients, including inpatient care, of which 26 belong to the National Hospital Organization, and the other is the National Center of Neurology and Psychiatry.Since 1999, Japanese muscular dystrophy research groups investigating nervous and mental disorder have been developing a database of cases treated at these 27 institutions.In that regard, we conducted a survey of inpatients with muscular dystrophy and other neuromuscular disorders based on data collected by the National Hospital Organization and National Center of Neurology and Psychiatry.Herein, we examined data obtained between 1999 and 2010 in order to evaluate the medical condition of inpatients with muscular dystrophy in Japan.

Subjects and methods
The database includes numbers of inpatients, gender, age, diagnosis, respiratory condition, nutritional state, number of death cases, causes of death, and other relevant findings from data collected annually on October 1 every year since 1999.We examined these data using longitudinal and horizontal analyses.

Sequential changes in total numbers of inpatients treated at muscular dystrophy wards of National Hospital Organization and National Center of Neurology and Psychiatry
The total numbers of inpatients treated at the muscular dystrophy wards of the National Hospital Organization and National Center of Neurology and Psychiatry were quite consistent during the examination period.The lowest number of inpatients was 2066 in 2007 and the highest was 2193 in 2003 (Fig. 1).
The number with myotonic dystrophy has gradually increased every year.

Sequential changes in respiratory care for inpatients and rate of mechanical ventilation dependence
The rate of mechanical ventilation use in 1999 was 37.9%, which gradually increased to 62.9% in 2010 (Fig. 5), while that for Duchenne muscular dystrophy patients in 1999 was 58.7% and gradually increased to 85.1% in 2010 (Fig. 2).Although the total number of inpatients with Duchenne muscular dystrophy gradually decreased, cases of non-invasive ventilation gradually increased and tracheostomy cases were also slightly increased.The rate of mechanical ventilation use for myotonic dystrophy patients in 1999 was 20.3%, which gradually increased to 55.7% in 2010 (Fig. 3).
The rate of mechanical ventilation use in 1999 was 37.9%, which gradually increased to 62.9% in 2010.

Changes in age distribution of inpatients in muscular dystrophy wards
The age distribution of inpatients in muscular dystrophy wards in 1999 showed 2 peaks.Those with Duchenne muscular dystrophy largely constituted the younger age peak in the 20s, while those with myotonic dystrophy larger constituted the older age peak in the 50s.These age peaks shifted to a higher range and became slightly flattened in 2009 (Fig. 6).

Sequential changes in mean age of inpatients
The mean age of the inpatients in 1999 was 36.6 years old, which gradually increased to 45.3 years old in 2010.That of Duchenne muscular dystrophy patients in 1999 was 23.6 years old, which gradually increased to 29.4 years old in 2010, while that of myotonic dystrophy patients changed only slightly from 51.4 years old in 1999 to 53.6 years old in 2010 (Fig. 7).Gradual changes in age distribution of inpatients with Duchenne muscular dystrophy was observed.The age peak in 1999 shifted to a higher range and became slightly flattened in 2009 (Fig. 8).The proportion of patients with Duchenne muscular dystrophy receiving oral nutrition in 1999 was 95.1%, which gradually decreased to 70.6% in 2010.In contrast, the number who required tube feeding, including a nasal nutrition tube and undergoing a percutaneous endoscopic gastrostomy, gradually increased to 107 in 2010.
PEG, percutaneous endoscopic gastrostomy Fig. 9. Sequential changes in numbers of Duchenne muscular dystrophy patients and those who underwent an endoscopic gastrostomy patients receiving oral nutrition.

Death case analysis
The total number of deaths reported from 2000 to 2010 was 1307, which ranged from 95-174 annually in a variable pattern (Fig. 10).The number of Duchenne muscular dystrophy patients who died was 409, while that of myotonic dystrophy patients was 363.
The mean age of death among Duchenne muscular dystrophy patients was 26.7 years old in 2000, which gradually increased to 35.1 years old by 2010.On the other hand, the mean age of death for myotonic dystrophy patients was 59.0 years old in 2000 and 59.1 years old in 2010, which was not significantly different (Fig. 10).
The most frequent cause of death among Duchenne muscular dystrophy patients was heart failure, accounting for 47%.As for myotonic dystrophy patients, the most frequent cause was respiratory disorders, such as respiratory failure and respiratory tract infection, which accounted for 64% (Fig. 11).

Proportional changes in numbers of inpatients in muscular dystrophy wards of each institution
Twenty-seven hospitals in Japan specialize in treatment of muscular dystrophy patients are not same in terms of types of muscular dystrophy of inpatient, disease severity, and actual care.

Sequential changes in respiratory conditions of Duchenne muscular dystrophy patients at each institution (1999~2009).
The total number of Duchenne muscular dystrophy patients treated from 1999 to 2009 was 1427.The changes in motor function of the patients were nearly uniform, whereas the therapeutic respiratory conditions varied among the institutions.
Figure 13 presents the respiratory conditions of the patients for the 11-year period from 1999 to 2009.In the 10s, almost patients keep voluntary respiratory function.In the 20s, various respiratory patterns are observed, which seem not to be different among the institutions.In more than 30s, there were apparent differences among the institutions.Some institutes have no tracheostomy older patients, which generation is generally supposed not to be compensated by non-invasive positive pressure ventilation and use tracheotomy ventilation.

Conclusion
Wards for patients with muscular dystrophy were originally established in Japan in 1964 and then gradually expanded throughout the country.As a result, approximate 2500 beds are now provided among 27 institutions.In the early days, many of the patients were boys with Duchenne muscular dystrophy, who received education in schools near the hospital where they received care.However, over time, regular public elementary and junior high schools began to accept disabled children, and such patients were then able to receive an education at schools in their home town.Thus, cases of admission for the purpose of education gradually decreased.
On the other hand, progress in therapeutic strategies for respiratory failure (American Thoracic Society Documents, 2004), heart failure (Ishikawa, 1999;Matsumura, 2010) and other complications associated with muscular dystrophy prolonged the life span of affected individuals (Bushby 2010a, b).Now, most inpatients admitted to a muscular dystrophy ward have a severe general condition and many are assisted by mechanical ventilation (Tatara, 2008).In addition, in terms of nutritional control (American Thoracic Society Documents, 2004; Bushby 2010b), the number of percutaneous endoscopic gastrostomy patients with Duchenne muscular dystrophy has gradually increased.Thus, the age and disease severity of inpatients have been gradually progressed with this changing environment.And social welfare systems related to muscular dystrophy wards in Japan also have been changing during this research.The social role of wards for inpatients with muscular dystrophy has been changing.The gradual increase of number of inpatients with amyotrophic lateral sclerosis means that the ward for patients with muscular dystrophy is no longer only for patients with muscular dystrophy.Present wards have purpose for care and treatment for severe disabilities, not limited to patients with muscular dystrophy.
There are some reports concerned with prognosis of patients with Duchenne muscular dystrophy from single institution belonging to the National Hospital Organization (Ishikawa, 2011;Matsumura, 2011).Just as these reports, we showed the increasing mean age of death among Duchenne muscular dystrophy patients.Although the most frequent cause of death among Duchenne muscular dystrophy patients was heart failure, the progression for cardioprotection therapy to cardiomyopathy (Ishikawa, 1999;Matsumura, 2010) improved the prognosis.
However, the present findings showed that there are apparent differences in regard to the proportion of inpatients and therapeutic conditions among institutions.Hereafter, these differences will be more remarkable.So far almost same therapy has been offered among the National Hospital Organization and National Center of Neurology and Psychiatry.However, these conditions will not continue and may influence the prognosis of patients with muscular dystrophy in Japan.
Social role of wards for patients with muscular dystrophy at establishment, offering patients with muscular dystrophy opportunities of education and treatment, has changed into offering severe disabilities care and treatment.We should consider how to manage these conditions.

Acknowledgments
This study was supported by a Research Grant for Nervous and Mental Disorders from the Ministry of Health, Labour and Welfare of Japan.
Institutions specializing in muscular dystrophy treatment in Japan (Fig. 14)

Fig. 1 .
Fig. 1.Total numbers of inpatients in muscular dystrophy wards of National Hospital Organization and National Center of Neurology and Psychiatry.

Fig. 2 .
Fig. 2. Sequential changes in number of inpatients with Duchenne muscular dystrophy and rate of mechanical ventilation dependence.

Fig. 3 .
Fig. 3. Sequential changes in number of inpatients with myotonic dystrophy and rate of mechanical ventilation dependence.

Fig. 4 .
Fig. 4. Sequential changes in number of inpatients with amyotrophic lateral sclerosis.

Fig. 5 .
Fig. 5. Sequential changes in respiratory care for inpatients and rate of mechanical ventilation dependence.
% of respiration www.intechopen.comDatabase of Wards for Patients with Muscular Dystrophy in Japan 251 Upper: 1999.Lower: 2009.The age distribution of inpatients in muscular dystrophy wards shifted to a higher range over time.

Fig. 6 .
Fig. 6.Changes in age distribution of inpatients in muscular dystrophy wards.

Fig. 8 .
Fig. 8. Changes in age distribution of inpatients with Duchenne muscular dystrophy.

Fig. 10 .
Fig. 10.Sequential numbers of deaths and mean age at death reported to the database.
Fig. 12. Changes in proportions of inpatients in muscular dystrophy wards of each institution Fig. 13.Sequential changes in respiratory conditions of Duchenne muscular dystrophy patients treated at each institution (1999~2009).

Fig. 14 .
Fig. 14.Institutions specializing in muscular dystrophy treatment in Japan