Background/Purpose: Fibromyalgia (FM) is characterized by chronic widespread pain and tenderness making it difficult to manage. Accounting for FM heterogeneity might elicit an improvement in patient treatment. Chronic diseases are a dynamic process with increasing and decreasing symptomology and clinical manifestations. Several diseases similar to FM have known chronicity trends; rheumatoid arthritis has stages indicated by disease progression, and according to the Centers for Disease Control and Prevention, three different disease courses exist. The objective of this study was to cluster patients into stages, or similar disease profiles, based on severity of FM (i.e., patient co-morbidities, regions of pain, and procedures), as well as time.

Methods: We identified 2,529 FM patients with a total of 79,570 clinical visits between January 1999 and February 2014 from an administrative claims data. Patients were clustered based on similarity of co-morbidities (symptom severity), region of pain (widespread pain), and procedures (treatment intensity) by implementing a sequence of unsupervised and supervised learning techniques. Text analysis and a review of physician notes were conducted to obtain secondary conditions and diseases to assist in the understanding of stage classification.

Results: There were four parent stages of FM identified and labeled: 1) regional FM with classic symptoms; 2) generalized FM with increasing widespread pain and some additional symptoms; 3) FM with advanced and associated conditions, increasing widespread pain, increased sleep disturbances, and chemical sensitivity; and 4) secondary FM reactive to disease. Approximately 45% of patient observations were reclassified when the constraints of time were lifted. Most notably, the rate of stage misclassification dramatically reduced from 11.2% to 4.4% when patients were reclassified based on exponential increases in disease severity as opposed to time. These findings lend support that FM stages are more characterized by disease severity and are less time-dependent.

Conclusion: Generally, patients increase in their symptom severity and region of pain by stage. Parallels are beginning to emerge between the different stages and presentations of underlying conditions. General clustering seems to be occurring but requires more research. Nonetheless, this work makes a case for the presence of FM stages in which important clinical ramifications exist that may lead to a more precise treatment approach for FM patients.

ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-four-stages-of-fibromyalgia-potential-for-more-precise-treatment-approaches/