Frank C. Arnett

The revised criteria for the classification of rheumatoid arthritis (RA) were formulated from a computerized analysis of 262 contemporary, consecutively studied patients with RA and 262 control subjects with rheumatic diseases other than RA (non-RA). The new criteria are as follows: 1) morning stiffness in and around joints lasting at least 1 hour before maximal improvement; 2) soft tissue swelling (arthritis) of 3 or more joint areas observed by a physician; 3) swelling (arthritis) of the proximal interphalangeal, metacarpophalangeal, or wrist joints; 4) symmetric swelling (arthritis); 5) rheumatoid nodules; 6) the presence of rheumatoid factor; and 7) radiographic erosions and/or periarticular osteopenia in hand and/or wrist joints. Criteria 1 through 4 must have been present for at least 6 weeks. Rheumatoid arthritis is defined by the presence of 4 or more criteria, and no further qualifications (classic, definite, or probable) or list of exclusions are required. In addition, a "classification tree" schema is presented which performs equally as well as the traditional (4 of 7) format. The new criteria demonstrated 91-94% sensitivity and 89% specificity for RA when compared with non-RA rheumatic disease control subjects.

The Bulletin on the Rheumatic Diseases has published all of the classification criteria for the rheumatic diseases to date. These new revised classification criteria for rheumatoid arthritis are very important as they should provide understanding of the possibly changing face of rheumatoid arthritis.

OBJECTIVE: To provide a single source for the best available estimates of the national prevalence of arthritis in general and of selected musculoskeletal disorders (osteoarthritis, rheumatoid arthritis, juvenile rheumatoid arthritis, the spondylarthropathies, systemic lupus erythematosus, scleroderma, polymyalgia rheumatica/giant cell arteritis, gout, fibromyalgia, and low back pain). METHODS: The National Arthritis Data Workgroup reviewed data from available surveys, such as the National Health and Nutrition Examination Survey series. For overall national estimates, we used surveys based on representative samples. Because data based on national population samples are unavailable for most specific musculoskeletal conditions, we derived data from various smaller survey samples from defined populations. Prevalence estimates from these surveys were linked to 1990 US Bureau of the Census population data to calculate national estimates. We also estimated the expected frequency of arthritis in the year 2020. RESULTS: Current national estimates are provided, with important caveats regarding their interpretation, for self-reported arthritis and selected conditions. An estimated 15% (40 million) of Americans had some form of arthritis in 1995. By the year 2020, an estimated 18.2% (59.4 million) will be affected. CONCLUSION: Given the limitations of the data on which they are based, this report provides the best available prevalence estimates for arthritis and other rheumatic conditions overall, and for selected musculoskeletal disorders, in the US population.

1. Among patients with SLE, 71 (51%) had significant neuropsychiatric problems during the course of the disease. In 52 (37%), the nervous system manifestations were secondary to SLE. 2. The most frequent manifestations were psychiatric dysfunction, seizures, long tract signs, cranial neuropathy, and peripheral neuropathy. 3. Psychiatric abnormalities secondary to SLE were characterized by organic features (present in 22 of 24) and by the association of neurologic lesions which were often diffuse or multifocal. 4. An abnormal cerebrospinal fluid was found in 32% of neuropsychiatric episodes in which specimens were obtained. The most frequently abnormal study was the electroencephalogram (71%), and the least frequent was the brain scan (8%). These studies did not correlate with specific clinical patterns. 5. In 63% of the patients, NP manifestations preceded the diagnosis of SLE or occurred within the first year of diagnosed disease, and in most episodes were associated with evidence of clinical and/or serologic activity of the underlying illness. 6. Only two clinical features showed significant and striking correlations with neuropsychiatric involvement, namely vasculitis and thrombocytopenia. The possible pathogenic implications have been discussed. 7. Only 2 of the 140 patients were felt to have steroid-induced psychoses. In approximately one-half of the NP episodes secondary to SLE, patients were receiving no corticosteriods on presentation. Of those developing while patients were on steroids, the majority occurred on low doses or after tapering from higher levels. 8. The immediate prognosis for improvement in neuropsychiatric function was good with 84% of episodes showing complete or partial resolution. Corticosteroids appeared to be of benefit in a substantial number of patients although their precise role is difficult to quantitate. 9. Five and 10 years survivals for the overall population were 94% and 82%, respectively. There were no significant differences in survival for patients with or without nervous system involvement.