The American College of Rheumatology 1991 revised criteria for the classification of global functional status in rheumatoid arthritis.

Objective: To develop and validate revised criteria for global functional status in rheumatoid arthritis (RA).

Methods: Revised criteria were formulated and tested for criterion and discriminant validity in 325 patients with RA.

Results: The revised criteria developed are as follows: class I = able to perform usual activities of daily living (self-care, vocational, and avocational); class II = able to perform usual self-care and vocational activities, but limited in avocational activities; class III = able to perform usual self-care activities but limited in vocational and avocational activities; class IV = limited in ability to perform usual self-care, vocational, and avocational activities. Usual self-care activities include dressing, feeding, bathing, grooming, and toileting; vocational and avocational activities are both patient-desired and age-, and sex-specific. The distribution properties of this classification schema were superior to those of the original Steinbrocker criteria. Mean Health Assessment Questionnaire scores were significantly (P less than 0.0001) different between, and increased across, the 4 classes.

Conclusion: Although there are limitations inherent in the use of global ordinal scales, the American College of Rheumatology revised criteria will be useful in describing the functional consequences of RA. A more detailed quantitative measure of physical disability should be used, however, for optimal monitoring of patients' clinical status in office practice and clinical research.