Postmarketing evidence of disease-modifying drugs in multiple sclerosis.

There is growing interest in the use of observational data to estimate treatment effects in chronic diseases such as multiple sclerosis (MS). The main results derived from postmarketing evaluations, in the last 2 years, of short-and long-term disease modifying drugs (DMDs) effectiveness will be reported in this Review. Moreover, some of the methodological improvements that may be useful to enhance the quality of observational studies will also be discussed.