To develop criteria for the classification of fibromyalgia, we studied 558 consecutive patients: 293 patients with fibromyalgia and 265 control patients. Interviews and examinations were performed by trained, blinded assessors. Control patients for the group with primary fibromyalgia were matched for age and sex, and limited to patients with disorders that could be confused with primary fibromyalgia. Control patients for the group with secondary-concomitant fibromyalgia were matched for age, sex, and concomitant rheumatic disorders. Widespread pain (axial plus upper and lower segment plus left- and right-sided pain) was found in 97.6% of all patients with fibromyalgia and in 69.1% of all control patients. The combination of widespread pain and mild or greater tenderness in greater than or equal to 11 of 18 tender point sites yielded a sensitivity of 88.4% and a specificity of 81.1%. Primary fibromyalgia patients and secondary-concomitant fibromyalgia patients did not differ statistically in any major study variable, and the criteria performed equally well in patients with and those without concomitant rheumatic conditions. The newly proposed criteria for the classification of fibromyalgia are 1) widespread pain in combination with 2) tenderness at 11 or more of the 18 specific tender point sites. No exclusions are made for the presence of concomitant radiographic or laboratory abnormalities. At the diagnostic or classification level, the distinction between primary fibromyalgia and secondary-concomitant fibromyalgia (as defined in the text) is abandoned.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/art.1780330203

The American College of Rheumatology 1990 Criteria for the Classification of Fibromyalgia. Report of the Multicenter Criteria Committee.

Objective To develop simple, practical criteria for clinical diagnosis of fibromyalgia that are suitable for use in primary and specialty care and that do not require a tender point examination, and to provide a severity scale for characteristic fibromyalgia symptoms. Methods We performed a multicenter study of 829 previously diagnosed fibromyalgia patients and controls using physician physical and interview examinations, including a widespread pain index (WPI), a measure of the number of painful body regions. Random forest and recursive partitioning analyses were used to guide the development of a case definition of fibromyalgia, to develop criteria, and to construct a symptom severity (SS) scale. Results Approximately 25% of fibromyalgia patients did not satisfy the American College of Rheumatology (ACR) 1990 classification criteria at the time of the study. The most important diagnostic variables were WPI and categorical scales for cognitive symptoms, unrefreshed sleep, fatigue, and number of somatic symptoms. The categorical scales were summed to create an SS scale. We combined the SS scale and the WPI to recommend a new case definition of fibromyalgia: (WPI > or =7 AND SS > or =5) OR (WPI 3-6 AND SS > or =9). Conclusion This simple clinical case definition of fibromyalgia correctly classifies 88.1% of cases classified by the ACR classification criteria, and does not require a physical or tender point examination. The SS scale enables assessment of fibromyalgia symptom severity in persons with current or previous fibromyalgia, and in those to whom the criteria have not been applied. It will be especially useful in the longitudinal evaluation of patients with marked symptom variability.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/acr.20140

The American College of Rheumatology preliminary diagnostic criteria for fibromyalgia and measurement of symptom severity.

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 or 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.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/1529-0131%28199805%2941%3A5%3C778%3A%3AAID-ART4%3E3.0.CO%3B2-V

Estimates of the prevalence of arthritis and selected musculoskeletal disorders in the United States

Objective. To determine the prevalence and characteristics of fibromyalgia in the general population.

Methods. A random sample of 3,006 persons in Wichita, KS, were characterized according to the presence of no pain, non-widespread pain, and widespread pain. A subsample of 391 persons, including 193 with widespread pain, were examined and interviewed in detail.

Results. The prevalence of fibromyalgia was 2.0% (95% confidence interval [95% CI] 1.4, 2.7) for both sexes, 3.4% (95% CI 2.3, 4.6) for women, and 0.5% (95% CI 0.0, 1.0) for men. The prevalence of the syndrome increased with age, with highest values attained between 60 and 79 years (>7.0% in women). Demographic, psychological, dolorimetry, and symptom factors were associated with fibromyalgia.

Conclusion. Fibromyalgia is common in the population, and occurs often in older persons. Characteristic features of fibromyalgia–pain threshold and symptoms–are similar in community and clinic populations, but overall severity, pain, and functional disability are more severe in the clinic population.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/art.1780380104

The prevalence and characteristics of fibromyalgia in the general population

Objective. To develop a fibromyalgia (FM) survey questionnaire for epidemiologic and clinical studies using a modification of the 2010 American College of Rheumatology Preliminary Diagnostic Criteria for Fibromyalgia (ACR 2010). We also created a new FM symptom scale to further characterize FM severity. Methods. The ACR 2010 consists of 2 scales, the Widespread Pain Index (WPI) and the Symptom Severity (SS) scale. We modified these ACR 2010 criteria by eliminating the physician’s estimate of the extent of somatic symptoms and substituting the sum of 3 specific self-reported symptoms. We also created a 0–31 FM Symptom scale (FS) by adding the WPI to the modified SS scale. We administered the questionnaire to 729 patients previously diagnosed with FM, 845 with osteoarthritis (OA) or with other noninflammatory rheumatic conditions, 439 with systemic lupus erythematosus (SLE), and 5210 with rheumatoid arthritis (RA). Results. The modified ACR 2010 criteria were satisfied by 60% with a prior diagnosis of FM, 21.1% with RA, 16.8% with OA, and 36.7% with SLE. The criteria properly identified diagnostic groups based on FM severity variables. An FS score ≥ 13 best separated criteria+ and criteria− patients, classifying 93.0% correctly, with a sensitivity of 96.6% and a specificity of 91.8% in the study population. Conclusion. A modification to the ACR 2010 criteria will allow their use in epidemiologic and clinical studies without the requirement for an examiner. The criteria are simple to use and administer, but they are not to be used for self-diagnosis. The FS may have wide utility beyond the bounds of FM, including substitution for widespread pain in epidemiological studies.

https://www.jrheum.org/content/jrheum/38/6/1113.full.pdf

Fibromyalgia criteria and severity scales for clinical and epidemiological studies: a modification of the ACR Preliminary Diagnostic Criteria for Fibromyalgia

Primary fibromyalgia (fibrositis): Clinical study of 50 patients with matched normal controls

Juvenile rheumatoid arthritis: a general review and report of 100 patients observed for 15 years.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/art.1780100608

Cancer and arthritis.

THE relation of fever to juvenile rheumatoid arthritis appears to have been largely overlooked in the period of almost seventy years since Still1 first called attention to certain distinctive pyrex...

John J. Calabro

Papers

Primary fibromyalgia (fibrositis): Clinical study of 50 patients with matched normal controls

Juvenile rheumatoid arthritis: a general review and report of 100 patients observed for 15 years.

Cancer and arthritis.

Fever Associated with Juvenile Rheumatoid Arthritis

Rash associated with juvenilerheumatoid arthritis