Danish validation of fibromyalgia criteria in a cohort of patients with chronic pain
Chronic pain syndromes are considered to share the same pathophysiology, with disturbances in pain modulation as the proposed cause of continued pain. Fibromyalgia (FM) is a well described subgroup defined by chronic widespread pain (CWP) and signs of generalized pressure pain hypersensitivity, and has traditionally been classified according to the ACR1990 criteria, where the presence of generalized hypersensitivity is estimated by a tender-point examination. New diagnostic criteria was proposed in 2010/11 and revised in 2016, abandoning the tender-point examination. These criteria are not validated in Danish, and have not been validated in a cohort of patients with different pain syndromes.
FM has traditionally been diagnosed by rheumatologists, and the gold standard for classification is the ACR-1990 criteria. Patients are classified as FM, if they have chronic widespread pain (CWP) for more than 3 months, with concomitant widespread mechanical hyperalgesia, defined as at least 11 out of 18 positive tender-points. The purpose of classification criteria is to be able to identify well defined homogeneous groups of patients for research purpose, and classification criteria must therefore have high specificity. The ACR-1990 criteria are shown to have high specificity in cohorts of patients with rheumatic diseases. The ACR1990 classification criteria have not been validated in at population of chronic pain patients.
New diagnostic criteria for FM were proposed in 2010/11, abandoning the tender-point examination. Diagnostic criteria must have high sensitivity, and these new criteria have been shown to have high sensitivity, when used in a cohort of patients with rheumatic diseases, but they seem to fail to diagnose FM correctly in a cohort of chronic pain patients. The reason for this could be that FM and other chronic pain syndromes share the same pathophysiology, with disturbances in pain modulation as the cause of continued pain, in spite of lack of peripheral pain drivers. In 2016, a revision of the 2010/11 criteria were proposed (ACR-2016 criteria), and they have been shown to improve the sensitivity of the criteria in cohorts of patients with different rheumatic diseases. The ACR-2016 criteria have not been validated in Danish, and have not been validated in a cohort of patients with chronic pain syndromes.
Alternative criteria have been proposed in 2013 from an independent research group (AltCr2013). The alternative criteria has not been validated in Danish and in a cohort of patients with chronic pain either.
Description of the cohort
The study is carried out in collaboration between Pain Centre Middelfart and Pain Centre South (OUH). One consultant from each center will include patients.
The ACR-2016 and Alt-2013 criteria are translated to Danish according to standardized guidelines: Forward translation, expert-panel back translation, pre-testing/interviewing and final version.
From November 2017, all patients referred to one of the two pain-centers, who have their first interview with one of the two involved consultants, will be invited to participate in the study. Based on medical history and tender-point examination, all the patients included in the study will be evaluated by the two consultants and given a clinical diagnosis of FM, CWP, Multifocal pain, regional pain or other pain. All patients will afterwards be classified according to the ACR1990, ACR2016 and Alt2013 criteria.
Data and biological material
The following data will be collected:
Collaborating researchers and departments
Pain Centre South, Odense University Hospital
- Consultant Karin Bruun Plesner, consultant, MD
- Morten Rune Blichfeldt-Eckhardt,consultant, PhD, MD
Pain Centre Middelfart, Middelfart Hospital
- Consultant Nina Kvorning, consultant, Dr.med., MD
- Hanne Irene Jensen, associate professor, PhD, MHSc, RN