Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement
Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.
The Course of FibromyalgiaA Long-Term Longitudinal Cohort Study.
Walitt5, Brian, Hauser3, Winfried, Hassett4, Afton, Katz2, Robert S., Wolfe1, Frederick
Fibromyalgia (FM) is a chronic condition in which treatment is of limited effectiveness. However, the ACR 2010 criteria study reported that 25% of FM patients improved sufficiently so that they did not meet classification criteria at follow-up. Other studies have also reported various degrees of improvement. Much of the uncertainty about the course of FM can be attributed to selection bias and non-standardized measures of improvement. In this report, we followed 1,555 criteria positive FM patients for a mean of 4.0 years (range 1.0 to 11.5 years) to determine the symptomatic course.
Patients were participants in a longitudinal study of FM outcomes. They were assessed semi-annually in 11,006 observations (6,251 pt-years). Assessments included the Widespread Pain Index, fatigue, sleep disturbance, functional status and a general measure of FM severity (the Fibromyalgianess Scale). Criteria status was assessed with a survey modification of the ACR 2010 diagnostic criteria. We used generalized estimating equations (GEE) to assess the rate of change of study variables over time and Cox regression to assess incidence of loss and regain of FM diagnostic status.
Patients switched between criteria positive and negative states. 716 patients became criteria negative during the study (44.0%), for an incident rate of 16.9 (15.7, 18.2) per 100 pt-years; and 378 patients (24.3%) who satisfied FM criteria at entry no longer satisfied criteria at the study close, an incident rate 6.0 (5.5, 6.6) per 100 pt-years. All FM related variables predicted the transition between positive and negative states. The strongest predictor was the 031 fibromyalgianess scale, which decreased by -.36 (0.32, 0.40) units annually. Other study variables also decreased during the study. Figure 1 shows fibromyalgianess in patients remaining criteria positive (23.8 ±4.5) and those who became criteria negative (12.9 ±4.2).
Figure 2 demonstrates minimum and maximum pain, symptom count, fatigue, and mood scores during follow-up.
FM patients often switch between criteria positive and negative states and have a wide variation in symptoms. These data indicate limitations in the usefulness of the discrete diagnosis of FM. Symptom severity, as opposed to diagnosis, appears to be more clinically reliable and relevant. The fluctuating nature of FM diagnosis has important implications for clinical care and treatment indications.
To cite this abstract, please use the following information:
Walitt, Brian, Hauser, Winfried, Hassett, Afton, Katz, Robert S., Wolfe, Frederick; The Course of FibromyalgiaA Long-Term Longitudinal Cohort Study. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :110