What exactly did the 2016 revision change from the 2010 criteria?▼
The 2016 revision made four changes to the 2010/2011 criteria. First and most important: it added a "generalized pain" criterion requiring pain in at least 4 of the 5 defined body regions. This addressed the finding that the 2010 criteria could incorrectly classify patients with severe regional pain disorders (e.g., bilateral rotator cuff disease, bilateral knee OA, and back pain) as having fibromyalgia. Jaw, chest, and abdominal pain are explicitly excluded from the region count. Second: it standardized the WPI minimum to 4 (Option B now reads WPI 4-6, not WPI 3-6). Third: it changed the duration wording from "symptoms present at a similar level for at least 3 months" to "symptoms generally present for at least 3 months," acknowledging that fibromyalgia symptoms fluctuate. Fourth: it removed the exclusion clause requiring that no other disorder explains the pain, replacing it with positive language affirming that fibromyalgia is valid even with other diagnoses.
Why are jaw, chest, and abdominal pain excluded from the generalized pain regions?▼
These regions were excluded from the generalized pain definition for two reasons. First, they represent overlapping territory with other common conditions: temporomandibular joint disorders (jaw), musculoskeletal chest pain or costochondritis (chest), and irritable bowel syndrome or functional abdominal pain (abdomen). Many non-fibromyalgia patients have pain in one or more of these regions, and including them would inflate the apparent "regionality" of pain. Second, the generalized pain definition was designed to differentiate fibromyalgia from peripheral or regional musculoskeletal disorders - these three areas were considered less central to that differentiation. Importantly, jaw, chest, and abdominal pain still count toward the WPI score; they just do not count when determining whether 4 of 5 regions are met.
How does the 2016 somatic symptom scoring differ from the 2010 version?▼
This represents the most operationally significant change for clinical practice. The 2010 criteria required a physician to estimate the overall somatic symptom burden from a 41-item checklist, assigning a score of 0-3 based on whether no symptoms, few (1-10), a moderate number (11-24), or many (25+) were present. This approach was inherently physician-dependent and difficult to standardize. The 2016 criteria replace this with three specific self-reportable items: (1) headaches, (2) pain or cramps in the lower abdomen, and (3) depression or depressive symptoms - each scored as present/absent (0 or 1). This means the 2016 somatic score is 0, 1, 2, or 3 based simply on how many of these three items are present. The change makes the criteria fully usable as a patient self-report questionnaire and eliminates physician subjectivity from the somatic component.
What are the 5 body regions and which WPI sites map to each?▼
The 5 regions are: (1) Left upper - left shoulder girdle, left upper arm, left lower arm; (2) Right upper - right shoulder girdle, right upper arm, right lower arm; (3) Left lower - left hip (buttock/trochanter), left upper leg, left lower leg; (4) Right lower - right hip (buttock/trochanter), right upper leg, right lower leg; (5) Axial - neck, upper back, lower back. A region is considered "active" (counts toward the 4-of-5 requirement) if the patient reports pain in any one or more of the sites within that region. The jaw (left and right), chest, and abdomen are the remaining 4 WPI sites that contribute to the WPI total but do not map to any of the 5 regions for generalized pain purposes.
Can fibromyalgia coexist with inflammatory diseases like RA or lupus in the 2016 criteria?▼
Yes, and this is explicitly stated as criterion 4 in the 2016 revision: "A diagnosis of fibromyalgia is valid irrespective of other diagnoses. A diagnosis of fibromyalgia does not exclude the presence of other clinically important illnesses." This is clinically crucial because fibromyalgia complicates approximately 20-30% of patients with rheumatoid arthritis, systemic lupus erythematosus, ankylosing spondylitis, and other inflammatory conditions. In these patients, fibromyalgia drives ongoing pain, fatigue, and poor sleep quality despite effective immunosuppressive therapy. Recognizing concurrent fibromyalgia helps explain why disease activity scores remain elevated in apparent remission, prevents inappropriate dose escalation of immunosuppressants, and allows for fibromyalgia-specific treatments (exercise, CBT, low-dose tricyclics, SNRIs, pregabalin/gabapentin) to be added.
How is the fibromyalgia severity (FS) score used in practice to monitor patients?▼
The FS score (WPI + SSS, range 0-31) was introduced in 2011 and carried forward through the 2016 revision. It serves as a continuous measure of fibromyalgia burden that can be used to: (1) track response to treatment over serial visits, where a meaningful clinically important difference is approximately 3-4 points; (2) quantify symptom burden in patients who formerly met criteria but may have improved below threshold; (3) compare fibromyalgia severity across patient populations in research. General bands used clinically: 0-12 mild, 13-19 moderate, 20-31 severe - though these were not formally derived through clinical trials. The FS score is particularly useful because it captures both pain distribution (WPI component) and multi-symptom burden (SSS component) in a single number.