Clinical and epidemiologic aspects of ankylosing spondylitis and spondyloarthropathies.

In the past decade the concept of spondyloarthropathy has become well established, and appropriate classification criteria have been developed. Now it is time to better define the terms in common use in order to facilitate scientific communication. Recently, new therapeutic approaches have been tested, but the design of some of these studies is weak. Clearly, the outcome of ankylosing spondylitis and spondyloarthritis is multidimensional. A number of new instruments for the assessment of ankylosing spondylitis are now available, but there is a need for core sets of outcome measures appropriate for the different settings in which assessment is done. Although criteria intended for use in epidemiologic studies might be useful in daily clinical practice to establish a diagnosis, improved recognition of the different elements of ankylosing spondylitis and spondyloarthritis requires more "problem orientation" and less "disease orientation."