Symptoms of Fibromyalgia According to the 2016 Revised Fibromyalgia Criteria in Chronic Pain Patients Referred to Multidisciplinary Pain Rehabilitation: Influence on Clinical and Experimental Pain Sensitivity.

UNLABELLED: Fibromyalgia (FM) is a condition with chronic widespread pain and signs of generalized pain hypersensitivity. FM has previously been classified according to the American College of Rheumatology-1990 criteria, where the presence of hypersensitivity is estimated by a tender point examination. Because of the limitations of these classification criteria, new diagnostic criteria have been proposed, abandoning this examination. This cross-sectional study investigated the prevalence of FM according to the revised 2016 FM criteria in a large cohort of chronic pain patients. Pain drawings, the FM Symptom Severity Scale, and questionnaires assessing manifestations of pain, pain-related disability, and psychological distress were collected from 1,343 patients with chronic nonmalignant pain referred to a multidisciplinary pain clinic. In addition, assessments of mechanical and thermal pain sensitivity were performed in 496 of the patients. Patients fulfilling the FM criteria (n = 498, 37%) reported significantly higher levels of pain, pain-related disability, psychological distress, and sensitivity to mechanical and heat stimuli (P < .05). Moreover, the proportion using opioids were significantly higher compared with patients not fulfilling the criteria (P = .015). Significant associations were found between heat and mechanical pain sensitivity (P < .001) indicating that patients who showed higher pain sensitivity to mechanical stimulation also showed higher pain sensitivity to thermal stimulation.

PERSPECTIVE: More than one-third of patients were classified as FM, and patients classified showed increased clinical and experimental pain profiles. Because no data were collected on whether the included patients had a clinical FM diagnosis, future studies validating the American College of Rheumatology-2016 criteria in a cohort of patients with chronic nonmalignant pain are warranted.