Disability, from rheumatoid arthritis

The choice of endpoints used in studies of new therapies may evolve over time as knowledge is gained about the natural history of the disease or the reliability of surrogate endpoints. Endpoints used to evaluate the benefits of new drugs are provided in Table 4.1 for a number of diseases. Many diseases are associated with numerous medical conditions of consequence to the patient (for example, pain and disability resulting from rheumatoid arthritis), which may be the target for a particular new therapy. 

Rheumatoid Arthritis. Figure 1 The development of disability overtime in a group of RA patients studied prior to the early 1990s. FDI = functional disease index where 1 = moderate disability, 2 = more marked disability, 3 = severe disability and 4 = very severe disability (from Wolfe, Cathey (1991) J Rheumatol 18 1298). 

About 1/4 of the people who get rheumatoid arthritis recover from the first attack without serious symptoms 1/2 suffer only minor discomfort while the remaining 1/4 develop chronic, progressive, disabling arthritis. 

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