The clinical epidemiology of multiple sclerosis.

A comprehensive knowledge of the natural course and prognosis of multiple sclerosis is of utmost importance for a physician to make it affordable in simple descriptive terms to a patient when personal and medical decisions are to be taken. It is still topical because the currently acknowledged disease-modifying agents only marginally alter the overall prognosis of the disease. It provides reference for evaluating the efficacy of a therapeutic intervention in clinical trials; clues for public health services, health insurance companies, and pharmaceutical industry in their respective activities; and insights into the pathophysiology and the treatment of multiple sclerosis. Precise, consistent, and reliable data from appropriate cohorts have become available and knowledge is fairly comprehensive.