Multiple sclerosis (MS) is a disease of autoimmune system which attacks the central nervous system and that is one of the most common inflammatory diseases and has caused a heavy disease burden on patients. In the world, the prevalence of MS is on the rise, and the annual growth rate of MS patients in Taiwan is much higher than the whole world (3.78 times). However, it has no discussion or study in references at present, and it is worthwhile to research. MS is not a fatal disease, but its complications make the mortality of its patients three times higher than that of general population. This study will explore the survival and the causes of death for MS patients in Taiwan by cohort study of fourteen years. In addition, in the recent years, the MS patients in Taiwan and the medical resource consumption has increased largely, and it is necessary to conduct the research.

The study population is based on the 'National Health Insurance Research Database' (NHIRD) from 2001 to 2015 provided by Taiwan Ministry of Health and Welfare. The subjects are diagnosed as MS patients based on the 'Registry for Catastrophic Illness'. First, the investigators will perform the statistical analysis of the incidence, the prevalence, the mortality and the trend analysis of the MS patients diagnosed each year. First, Kaplan-Meier method will be employed to examine the survival curves. Next, Cox proportional hazards model will be used to analyze the survival and related factors. Last, multiple regression analysis will be then performed to analyze the influence of independent variables on patients' medical utilization in each year.

In response to the lack of data on population-based epidemiological studies on MS diseases in Asia, this research wishes to fill the gaps in the studies of global prevention and analyze the patient's survival, mortality risk factors and the medical utilization as a reference for national health policies.

Inclusion Criteria:

• The subjects are diagnosed as MS patients

Exclusion Criteria:

• The subjects are not diagnosed as MS patients

The study population is based on the 'National Health Insurance Research Database' (NHIRD) from 2001 to 2015 provided by Taiwan Ministry of Health and Welfare.