Performance of the 2016 diagnostic criteria for fibromyalgia in a tertiary care pain rehabilitation setting: a diagnostic accuracy study

Fibromyalgia: A Review of the Pathophysiological Mechanisms and Multidisciplinary Treatment Strategies

Fibromyalgia is a syndrome characterized by chronic widespread musculoskeletal pain, which may or may not be associated with muscle or joint stiffness, accompanied by other symptoms such as fatigue, sleep disturbances, anxiety, and depression. It is a highly prevalent condition globally, being considered the third most common musculoskeletal disorder, following lower back pain and osteoarthritis. It is more prevalent in women than in men, and although it can occur at any age, it is more common between the ages of thirty and thirty-five. Although the pathophysiology and etiopathogenesis remain largely unknown, three underlying processes in fibromyalgia have been investigated. These include central sensitization, associated with an increase in the release of both excitatory and inhibitory neurotransmitters; peripheral sensitization, involving alterations in peripheral nociceptor signaling; and inflammatory and immune mechanisms that develop concurrently with the aforementioned processes. Furthermore, it has been determined that genetic, endocrine, psychological, and sleep disorders may influence the development of this pathology. The accurate diagnosis of fibromyalgia remains challenging as it lacks specific diagnostic biomarkers, which are still under investigation. Nonetheless, diagnostic approaches to the condition have evolved based on the use of scales and questionnaires for pain identification. The complexity associated with this pathology makes it difficult to establish a single effective treatment. Therefore, treatment is multidisciplinary, involving both pharmacological and non-pharmacological interventions aimed at alleviating symptoms. The non-pharmacological treatments outlined in this review are primarily related to physiotherapy interventions. The effectiveness of physical exercise, both on land and in water, as well as the application of electrotherapy combined with transcranial therapy and manual therapy has been highlighted. All of these interventions aim to improve the quality of life of patients highly affected by fibromyalgia.

Health inequities and societal costs for patients with fibromyalgia and their spouses: a Danish cohort study

OBJECTIVE

To assess the burden of illness of people with fibromyalgia (FM) and their spouses compared with selected match populations in Denmark.

METHODS

Population-based, cohort case-control study using data from Danish registries from 1994 to 2021. Individuals with an FM diagnosis were identified from the National Patient Register (2008-2019) and randomly matched to a 1:4 general population comparator. Spouses or persons co-living with subjects with FM at the time of diagnosis were compared with matched comparator spouses. Healthcare and societal costs, socioeconomic status and occurrence of comorbidities were evaluated for subjects with FM, spouses and controls.

RESULTS

9712 subjects with FM (94.9% females, mean age 50 years) and 5946 spouses were included. At year of diagnosis, subjects with FM had significantly more comorbidities compared with controls, including significantly more comorbid rheumatic disorders. The highest risk at the time of FM diagnosis was a comorbid diagnosis of ankylosing spondylitis (OR 7.0, 95% CI 4.9 to 10.0). Significantly more comorbidities were also observed in spouses. Subjects with FM and spouses had higher healthcare and public transfer costs and lower income from employment at all timepoints. Loss of income from employment in subjects with FM occurred years before establishment of the FM diagnosis. The employment rate after diagnosis was 22%. 10 years after the FM diagnosis, 50% received disability pension as compared with 11% of matched controls. The observed net average increased societal cost for subjects with FM amounted to €27 193 per patient-year after diagnosis.

CONCLUSION

FM has major health and socioeconomic consequences for patients, their partners and society and call for improved healthcare strategies matching patients' needs.

Naltrexone 6 mg once daily versus placebo in women with fibromyalgia: a randomised, double-blind, placebo-controlled trial

BACKGROUND

Low-dose naltrexone is used to treat fibromyalgia despite minimal evidence for its efficacy. This trial aimed to investigate whether 12-week treatment with 6 mg low-dose naltrexone was superior to placebo for reducing pain in women with fibromyalgia.

METHODS

We did a single-centre, randomised, double-blind, placebo-controlled trial in Denmark. We enrolled women aged 18-64 years who were diagnosed with fibromyalgia. Participants were randomly assigned 1:1 to receive low-dose naltrexone (6 mg) or an identical-appearing placebo, using a computerised algorithm with no stratifications applied. Participants, investigators, outcome assessors, and statistical analysts were all masked to treatment allocation. The primary outcome was change in pain intensity on an 11-point numeric rating scale from baseline to week 12, in the intention-to-treat population. Safety was assessed in participants in the intention-to-treat population who received at least one dose of their allocated intervention. This trial was registered with ClincalTrials.gov (NCT04270877) and EudraCT (2019-000702-30).

FINDINGS

We screened 158 participants for eligibility from Jan 6, 2021, to Dec 27, 2022, and 99 patients were randomly assigned to low-dose naltrexone (n=49) or placebo (n=50). The mean age was 50·6 years (SD 8·8), one (1%) of 99 participants was Arctic Asian and 98 (99%) were White. No participants were lost to follow-up. The mean change in pain intensity was -1·3 points (95% CI -1·7 to -0·8) in the low-dose naltrexone group and -0·9 (-1·4 to -0·5) in the placebo group, corresponding to a between-group difference of -0·34 (-0·95 to 0·27; p=0·27, Cohen's d 0·23). Discontinuations due to adverse events were four (8%) of 49 in the low-dose naltrexone group and three (6%) of 50 in the placebo group. 41 (84%) of 49 patients in the low-dose naltrexone group had an adverse event versus 43 (86%) of 50 in the placebo group. One serious adverse event occurred in the placebo group and no deaths occurred.

INTERPRETATION

This study did not show that treatment with low-dose naltrexone was superior to placebo in relieving pain. Our results indicate that low-dose naltrexone might improve memory problems associated with fibromyalgia, and we suggest that future trials investigate this further.

FUNDING

The Danish Rheumatism Association, Odense University Hospital, Danielsen's Foundation, and the Oak Foundation.

Modulation of Central Nociceptive Transmission by Manual Pressure Techniques in Patients with Migraine: An Observational Study

Background: Manual pressure in the upper cervical spine is used to provoke and reduce the familiar migraine headache. Information is scarce on the segmental levels, myofascial structure provocation, and reduction occurrences. The required dosage (amount of pressure, number of repetitions, and duration) has not been objectified yet. Methods: Prospective observational study. Thirty patients with migraine were examined interictally. Manual pressure was applied at four sites: the posterior arch of C1, the articular pillar of C2, the rectus capitis posterior major muscle, and the obliquus capitis inferior muscle, bilaterally. On sites where the familiar headache was provoked, the pressure was sustained to induce pain reduction (three repetitions). Provocation of familiar headache (yes/no), headache intensity (numerical pain rating scale), time to obtain a reduction of the headache (seconds), and applied pressure (g/cm2) were recorded. Results: Provocation of the familiar headache occurred at the posterior arches C1 in 92%, and at one of the articular pillars of C2 in 65.3% of cases. At one of the rectus capitis major muscles, the familiar headache was provoked in 84.6% of cases; at one of the oblique capitis inferior muscles, the familiar headache was provoked in 76.9% of cases. The applied mean pressure ranged from 0.82 to 1.2 kg/cm2. Maintaining the pressure reduced headache pain intensity significantly between the start and end of each of the three consecutive trials (p < 0.04). This reduction occurred faster in the third application than in the first application (p = 0.03). Conclusion: Manual pressure at upper cervical segments provokes familiar referred migraine headaches, with low manual pressure. Maintaining the pressure reduces the referred head pain significantly, indicating modulation of central nociceptive transmission.

The Evolution of Fibromyalgia, Its Concepts, and Criteria

Fibromyalgia developed in the 1950s from a substrate of difficult to explain regional and widespread pain mixed with symptoms of psychosocial distress. Controversies regarding psychological issues were common. Multiple criteria arose to define the disorder, but each identified a different set of patients. The identification of widespread pain as a criterion changed the nature of the disorder by effectively eliminating regional pain as a component condition. The easy-to-measure and relatively reliable widespread pain criterion then came to define the disorder. In the primary care community, diagnostic criteria were largely ignored, and a substantial fraction of diagnosed patients with lower pain scores, particularly women and those with high non-pain symptom scores, were diagnosed. Non-pain symptoms were added back to the fibromyalgia definition and criteria in 2010. Recognition grew that fibromyalgia fit the description of a functional somatic disorder. The idea of fibromyalgia as a primary pain disorder with a neurobiological basis contended with fibromyalgia as a broader biopsychosocial disorder. It is increasingly recognized that fibromyalgia represents a dimensional, non-binary condition and that features of fibromyalgia extend to persons who do not satisfy the criteria. Severity assessments are now available but rarely used. The course of fibromyalgia is not well studied, and improvement and remission criteria have not been successfully defined. The future of fibromyalgia as a discrete disorder remains uncertain as features of fibromyalgia are increasingly observed in patients with multiple different medical conditions.