Ätiologie und Pathophysiologie des Fibromyalgiesyndroms

Measuring interpersonal trauma: Development and validation of the German version of the victimization experience schedule (VES)

OBJECTIVE

Interpersonal victimization experiences (VEs) significantly affect mental and physical health, particularly in disorders associated with life-time adversities, like fibromyalgia syndrome (FMS) and major depressive disorder (MDD). However, assessing VEs comprehensively remains challenging due to limited tools that encompass sub-traumatic events, such as bullying or discrimination, and contextual dimensions. We aimed to address this gap by validating the Victimization Experience Schedule (VES) in German, examining its reliability, and assessing VEs in clinical populations with FMS and MDD.

METHODS

We investigated the relationship between VEs and clinical symptoms in individuals with FMS, MDD and healthy controls (N = 105) in a case-control study. We also analyzed correlations between different types of VEs and categories of early childhood abuse and posttraumatic-stress-disorder instruments. Additionally, we validated our findings in an independent sample of individuals with FMS (N = 97) from a clinical study.

RESULTS

We observed excellent inter-rater reliability (Kw = 0.90-0.99), and VEs assessed using the VES were in alignment with subcategories of early childhood abuse. The prevalence of VEs extended beyond the categories covered by traditional survey instruments and was higher in individuals with MDD (4.0 ± 2.6) and FMS (5.9 ± 3.1) compared to controls (1.5 ± 1.7). We consistently identified a significant association between the number of VEs, the associated subjective distress, and clinical scores. Furthermore, distinct correlation patterns between VEs and clinical outcomes emerged across different cohorts.

CONCLUSION

Our study emphasizes the VES's value in understanding VEs within MDD and FMS. These experiences span from traumatic to sub-traumatic and correlate with posttraumatic-stress and clinical symptoms, underscoring the VES's importance as an assessment tool.

Fibromyalgia-associated hyperalgesia is related to psychopathological alterations but not to gut microbiome changes

Fibromyalgia-syndrome (FMS) is a complex disease characterized by chronic widespread pain and additional symptoms including depression, cognitive dysfunction ("fibro-fog") and maldigestion. Our research team examined whether FMS-related pain parameters assessed by quantitative sensory testing (QST) and psychological disturbances are accompanied by alterations of the fecal microbiome. We recruited 25 patients with FMS and 26 age- and sex-matched healthy controls. Medical background, food habits, psychopathology and quality of life were assessed through questionnaires. Stool samples were analyzed by 16S rRNA gene amplification and sequencing. QST was performed according to the protocol of the German Network for Neuropathic Pain. QST showed that both lemniscal and spinothalamic afferent pathways are altered in FMS patients relative to healthy controls and that peripheral as well as central pain sensitization processes are manifest. Psychometric assessment revealed enhanced scores of depression, anxiety and stress. In contrast, neither the composition nor the alpha- and beta-diversity of the fecal microbiome was changed in FMS patients. FMS patients segregate from healthy controls in various parameters of QST and psychopathology, but not in terms of composition and diversity of the fecal microbiome. Despite consideration of several confounding factors, we conclude that the contribution of the gut microbiome to the pathophysiology of FMS is limited.

"My private theory is that it's all in the head": Understandings of chronic widespread pain among social workers from municipality job centers in Denmark

People with chronic widespread pain (CWP) are often unfit for work, and consequently they are dependent on the municipality job center to receive social support and sickness benefits. The job center's case management is based on a social worker's assessment of the citizen's health condition. This qualitative study investigates social workers' understandings of CWP. Interviews were carried out with 12 social workers. The results showed that the participants predominantly experienced the citizens' illnesses as psychosocially mediated-referring to trauma, or a lack of meaning in the citizens' lives. Only a few participants mentioned possibilities for somatic explanations of CWP.

Tramadol for management of fibromyalgia pain and symptoms: Systematic review

BACKGROUND

Fibromyalgia is a heterogeneous condition that appears to be associated with physiological and biochemical disturbances of pain modulation, and that consequently affects numerous other facets of life. Tramadol is currently being explored as an option to manage fibromyalgia pain and other symptoms because of its inhibitory activity of reuptake of neurotransmitters, but its safety and efficacy have not yet been established in these patients.

OBJECTIVE

To evaluate the effectiveness and safety of tramadol on the management of symptoms of the syndrome.

METHODS

We searched CENTRAL, MEDLINE, EMBASE, LILACS, Opengrey, ClinicalTrials.gov and WHO-ICTRP for randomised controlled trials analysing the association between tramadol used for fibromyalgia either single-agent or in combination with other drugs. Two reviewers independently extracted data and assessed risk of bias using the Cochrane risk-of-bias tool for all included studies. Quality of the evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE).

RESULTS

Four RCTs comprising 459 patients were included. Tramadol-either as a single-agent or in combination with an antidepressant or analgesic-had a positive effect on pain. Tramadol combined with analgesic showed improved quality of life over placebo as measured by the Fibromyalgia Impact Questionnaire at 91 days. However, this difference did not hold for tramadol as a single agent against placebo. The evidence in these articles was rated "low" using the GRADE approach. No serious adverse events were reported. No improvement in depression and quality of sleep were observed.

CONCLUSIONS

This systematic review found a dearth of clinical trials on tramadol in patients with fibromyalgia. Although the combination of monoamine and opioid mechanism of tramadol has shown positive effects for fibromyalgia, the available evidence is not sufficient to support or refute the use of tramadol in clinical practice for pain or symptom management. Protocol registration number in the PROSPERO database: CRD42017062139.

5'UTR polymorphism in the serotonergic receptor HTR3A gene is differently associated with striatal Dopamine D2/D3 receptor availability in the right putamen in Fibromyalgia patients and healthy controls-Preliminary evidence

BACKGROUND

Extensive literature has investigated the role of serotonin (5-HT) in the control of the central dopamine (DA) systems, and their dysfunction in the pathological conditions. 5-HT stimulates the local DA release in striatal regions via activation of various receptors including serotonin receptor-3 (5-HT3). Several studies have related polymorphisms (SNPs) in the serotonin receptor-3 (HTR3) genes to be associated with the pain modulation and endogenous pain suppression. A few studies suggested a functional role of 5'UTR SNP in the serotonergic receptor HTR3A gene (rs1062613) in the development of the chronic pain and Fibromyalgia syndrome (FMS) in particular. Here, we investigated the effect of a 5'UTR SNP in the serotonergic receptor HTR3A gene (rs1062613) on striatal dopamine D2/D3 receptor (DRD2) availability and reward-associated DA release in response to unpredictable monetary rewards in 23 women with FMS and 17 age-matched healthy female controls. Furthermore, we aimed to examine if SNP rs1062613 is associated with thermal pain and pain tolerance thresholds.

METHODS

We used PET and [¹¹ C]raclopride to assess the DRD2 availability. In the same participants we used the [¹¹ C]raclopride PET bolus-plus-infusion method to measure the [¹¹ C]raclopride receptor binding potential (ΔBP) between an unpredictable reward condition and a sensorimotor control condition. DRD2 availability and ΔBP were assessed in MRI-based striatal regions of interest. Thermal pain and pain tolerance thresholds were assessed outside the scanner.

RESULTS

The frequency of SNP rs1062613 genotype differed significantly between groups, indicating that CC homozygotes were more frequent in FMS patients (82.6%) than in healthy controls (41.3%). Our results showed a significant main effect of SNP rs1062613 on [¹¹ C]raclopride binding potential in the right caudate nucleus indicating a higher DRD2 receptor availability for CC-genotype of this SNP. Furthermore, we found a significant group × SNP interaction on [¹¹ C]raclopride binding potential in the right putamen, indicating a higher DRD2 availability in T-carriers compared to CC genotype of SNP rs1062613 in FMS patients, whereas this effect was not present in healthy controls. However, we did not find an influence of SNP rs1062613 on reward-related DA release. In addition, there was no association between SNP rs1062613 and pain threshold or pain tolerance threshold in our data.

CONCLUSION

These preliminary results indicate that SNP rs1062613 in the serotonergic receptor HTR3A gene possibly modulates the DRD2 receptor availability.

Cortisol and Subjective Stress Responses to Acute Psychosocial Stress in Fibromyalgia Patients and Control Participants

OBJECTIVE

Hypothalamic-pituitary-adrenal axis dysfunction may play a role in fibromyalgia (FM) pathogenesis but it remains understudied in this disorder. Furthermore, early childhood adversities (ECA) are common in FM, but whether they moderate stress reactivity is unknown. Hence, we investigated cortisol and subjective responses to acute psychosocial stress in FM and controls, while adjusting for ECA.

METHODS

Twenty-seven female FM patients and 24 age-matched female controls were recruited in a tertiary care center and through advertisements, respectively. The Childhood Trauma Questionnaire was used to measure ECA history. Salivary cortisol levels and subjective stress ratings were measured at multiple time points before and after the Trier Social Stress Test (TSST) was administered.

RESULTS

Significant main effects of group [F(1,43) = 7.04, p = .011, lower in FM] and ECA [F(1,43) = 5.18, p = .028, higher in participants with ECA] were found for cortisol responses. When excluding controls with ECA (n = 5), a significant group-by-time interaction was found [F(6,39) = 2.60, p = .032], driven by a blunted response to the stressor in FM compared with controls (p = .037). For subjective stress responses, a significant main effect of group [F(1,45) = 10.69, p = .002, higher in FM] and a trend toward a group-by-time interaction effect [F(6,45) = 2.05, p = .078, higher in FM 30 minutes before and 30 and 75 minutes after the TSST, and impaired recovery (difference immediately after - 30 minutes after the TSST) in FM] were found.

CONCLUSIONS

Blunted cortisol responsivity to the TSST was observed in FM patients compared with controls without ECA. FM patients had higher subjective stress levels compared with controls, particularly at baseline and during recovery from the TSST. In FM patients, ECA history was not associated with cortisol or subjective stress levels or with responsivity to the TSST. Future research should investigate the mechanisms underlying hypothalamic-pituitary-adrenal axis dysregulation in FM.

Increased cutaneous miR-let-7d expression correlates with small nerve fiber pathology in patients with fibromyalgia syndrome

Fibromyalgia syndrome (FMS) is a chronic widespread pain condition probably comprising subgroups with different underlying pathomechanisms. There is increasing evidence for small nerve fiber impairment in subgroups of patients with FMS. MicroRNAs (miRNAs) regulate molecular factors determining nerve de- and re-generation. We investigated whether systemic and cutaneous miRNA expression in patients with FMS is related to small nerve fiber pathology. We confirmed previous findings of disturbed small fiber function and reduced intraepidermal nerve fiber density in subgroups of patients with FMS. We found 51 aberrantly expressed miRNAs in white blood cells of patients with FMS, of which miR-let-7d correlated with reduced small nerve fiber density in patients with FMS. Furthermore, we demonstrated miR-let-7d and its downstream target insulin-like growth factor-1 receptor as being aberrantly expressed in skin of patients with FMS with small nerve fiber impairment. Our study gives further evidence of small nerve fiber pathology in FMS subgroups and provides a missing link in the pathomechanism that may lead to small fiber loss in subgroups of patients with FMS.

WITHDRAWN: Anticonvulsants for fibromyalgia

BACKGROUND

Fibromyalgia (FM) is a clinically well-defined chronic condition of unknown aetiology characterised by chronic widespread pain that often co-exists with sleep problems and fatigue. People often report high disability levels and poor health-related quality of life (HRQoL). Drug therapy focuses on reducing key symptoms and disability, and improving HRQoL. Anticonvulsants (antiepileptic drugs) are drugs frequently used for the treatment of chronic pain syndromes.

OBJECTIVES

To assess the benefits and harms of anticonvulsants for treating FM symptoms.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 8, 2013), MEDLINE (1966 to August 2013), PsycINFO (1966 to August 2013), SCOPUS (1980 to August 2013) and the reference lists of reviewed articles for published studies and www.clinicaltrials.gov (to August 2013) for unpublished trials.

SELECTION CRITERIA

We selected randomised controlled trials of any formulation of anticonvulsants used for the treatment of people with FM of any age.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted the data of all included studies and assessed the risks of bias of the studies. We resolved discrepancies by discussion.

MAIN RESULTS

We included eight studies: five with pregabalin and one study each with gabapentin, lacosamide and levetiracetam. A total of 2480 people were included into anticonvulsants groups and 1099 people in placebo groups. The median therapy phase of the studies was 13 weeks. The amount and quality of evidence were insufficient to draw definite conclusions on the efficacy and safety of gabapentin, lacosamide and levetiracetam in FM. The amount and quality of evidence was sufficient to draw definite conclusions on the efficacy and safety of pregabalin in FM. Therefore, we focused on our interpretation of the evidence for pregabalin due to our greater certainty about its effects and its greater relevance to clinical practice. All pregabalin studies had a low risk of bias. Reporting a 50% or greater reduction in pain was more frequent with pregabalin use than with a placebo (risk ratio (RR) 1.59; 95% confidence interval (CI) 1.33 to 1.90; number needed to treat for an additional beneficial outcome (NNTB) 12; 95% CI 9 to 21). The number of people who reported being 'much' or 'very much' improved was higher with pregabalin than with placebo (RR 1.38; 95% CI 1.23 to 1.55; NNTB 9; 95% CI 7 to 15). Pregabalin did not substantially reduce fatigue (SMD -0.17; 95% CI -0.25 to -0.09; 2.7% absolute improvement on a 1 to 50 scale) compared with placebo. Pregabalin had a small benefit over placebo in reducing sleep problems by 6.2% fewer points on a scale of 0 to 100 (standardised mean difference (SMD) -0.35; 95% CI -0.43 to -0.27). The dropout rate due to adverse events was higher with pregabalin use than with placebo use (RR 1.68; 95% CI 1.36 to 2.07; number needed to treat for an additional harmful outcome (NNTH) 13; 95% CI 9 to 23). There was no significant difference in serious adverse events between pregabalin and placebo use (RR 1.03; 95% CI 0.71 to 1.49). Dizziness was reported as an adverse event more frequently with pregabalin use than with placebo use (RR 3.77; 95% CI 3.06 to 4.63; NNTH 4; 95% CI 3 to 5).

AUTHORS' CONCLUSIONS

The anticonvulsant, pregabalin, demonstrated a small benefit over placebo in reducing pain and sleep problems. Pregabalin use was shown not to substantially reduce fatigue compared with placebo. Study dropout rates due to adverse events were higher with pregabalin use compared with placebo. Dizziness was a particularly frequent adverse event seen with pregabalin use. At the time of writing this review, pregabalin is the only anticonvulsant drug approved for treating FM in the US and in 25 other non-European countries. However, pregabalin has not been approved for treating FM in Europe. The amount and quality of evidence were insufficient to draw definite conclusions on the efficacy and safety of gabapentin, lacosamide and levetiracetam in FM.

Severe forms of fibromyalgia with acute exacerbation of pain: costs, comorbidities, and length of stay in inpatient care

Background and purpose

As a disease of the musculoskeletal system, fibromyalgia is becoming increasingly important, because of the direct and indirect costs to health systems. The purpose of this study of health economics was to obtain information about staff costs differentiated by service provider, and staff and material costs of the nonmedical infrastructure in inpatient care.

Patients and methods

This study looked at 263 patients who received interdisciplinary inpatient treatment for severe forms of fibromyalgia with acute exacerbation of pain between 2011 and 2014. Standardized cost accounting and an analysis of additional diagnoses were performed.

Results

The average cost per patient was €3,725.84, with staff and material costs of the nonmedical infrastructure and staff costs of doctors and nurses accounting for the highest proportions of the costs. Each fibromyalgia patient had an average of 6.1 additional diagnoses.

Conclusion

Severe forms of fibromyalgia are accompanied by many concomitant diseases and associated with both high clinical staff costs and high medical and nonmedical infrastructure costs. Indication-based cost calculations provide important information for health policy and hospital managers if they include all elements that incur costs in both a differentiated and standardized way.

Oral nonsteroidal anti-inflammatory drugs for fibromyalgia in adults

BACKGROUND

Oral nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used in the treatment of pain in fibromyalgia, despite being considered not to be effective.

OBJECTIVES

To assess the analgesic efficacy, tolerability (drop-out due to adverse events), and safety (serious adverse events) of oral nonsteroidal anti-inflammatory drugs for fibromyalgia in adults.

SEARCH METHODS

We searched CENTRAL, MEDLINE, and Embase for randomised controlled trials from inception to January 2017. We also searched the reference lists of retrieved studies and reviews, and online clinical trial registries.

SELECTION CRITERIA

We included randomised, double-blind trials of two weeks' duration or longer, comparing any oral NSAID with placebo or another active treatment for relief of pain in fibromyalgia, with subjective pain assessment by the participant.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed trial quality and potential bias. Primary outcomes were participants with substantial pain relief (at least 50% pain relief over baseline or very much improved on Patient Global Impression of Change scale (PGIC)) or moderate pain relief (at least 30% pain relief over baseline or much or very much improved on PGIC), serious adverse events, and withdrawals due to adverse events; secondary outcomes were adverse events, withdrawals due to lack of efficacy, and outcomes relating to sleep, fatigue, and quality of life. Where pooled analysis was possible, we used dichotomous data to calculate risk difference (RD) and number needed to treat for an additional beneficial outcome (NNT), using standard methods. We assessed the quality of the evidence using GRADE and created a 'Summary of findings' table.

MAIN RESULTS

Our searches identified six randomised, double-blind studies involving 292 participants in suitably characterised fibromyalgia. The mean age of participants was between 39 and 50 years, and 89% to 100% were women. The initial pain intensity was around 7/10 on a 0 to 10 pain scale, indicating severe pain. NSAIDs tested were etoricoxib 90 mg daily, ibuprofen 2400 mg daily, naproxen 1000 mg daily, and tenoxicam 20 mg daily; 146 participants received NSAID and 146 placebo. The duration of treatment in the double-blind phase varied between three and eight weeks.Not all studies reported all the outcomes of interest. Analyses consistently showed no significant difference between NSAID and placebo: substantial benefit (at least 50% pain intensity reduction) (risk difference (RD) -0.07 (95% confidence interval (CI) -0.18 to 0.04) 2 studies, 146 participants; moderate benefit (at least 30% pain intensity reduction) (RD -0.04 (95% CI -0.16 to 0.08) 3 studies, 192 participants; withdrawals due to adverse events (RD 0.04 (95% CI -0.02 to 0.09) 4 studies, 230 participants; participants experiencing any adverse event (RD 0.08 (95% CI -0.03 to 0.19) 4 studies, 230 participants; all-cause withdrawals (RD 0.03 (95% CI -0.07 to 0.14) 3 studies, 192 participants. There were no serious adverse events or deaths. Although most studies had some measures of health-related quality of life, fibromyalgia impact, or other outcomes, none reported the outcomes beyond saying that there was no or little difference between the treatment groups.We downgraded evidence on all outcomes to very low quality, meaning that this research does not provide a reliable indication of the likely effect. The likelihood that the effect could be substantially different is very high. This is based on the small numbers of studies, participants, and events, as well as other deficiencies of reporting study quality allowing possible risks of bias.

AUTHORS' CONCLUSIONS

There is only a modest amount of very low-quality evidence about the use of NSAIDs in fibromyalgia, and that comes from small, largely inadequate studies with potential risk of bias. That bias would normally be to increase the apparent benefits of NSAIDs, but no such benefits were seen. Consequently, NSAIDs cannot be regarded as useful for treating fibromyalgia.

Gabapentin for fibromyalgia pain in adults

BACKGROUND

This review replaces part of an earlier review that evaluated gabapentin for both neuropathic pain and fibromyalgia, now split into separate reviews for the two conditions. This review will consider pain in fibromyalgia only.Fibromyalgia is associated with widespread pain lasting longer than three months, and is frequently associated with symptoms such as poor sleep, fatigue, depression, and reduced quality of life. Fibromyalgia is more common in women.Gabapentin is an antiepileptic drug widely licensed for treatment of neuropathic pain. It is not licensed for the treatment of fibromyalgia, but is commonly used because fibromyalgia can respond to the same medicines as neuropathic pain.

OBJECTIVES

To assess the analgesic efficacy of gabapentin for fibromyalgia pain in adults and the adverse events associated with its use in clinical trials.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) via the Cochrane Register of Studies Online, MEDLINE via Ovid and Embase via Ovid from inception to 24 May 2016. We also searched the reference lists of retrieved studies and reviews, and searched online clinical trial registries.

SELECTION CRITERIA

Randomised, double-blind trials of eight weeks' duration or longer for treating fibromyalgia pain in adults, comparing gabapentin with placebo or an active comparator.

DATA COLLECTION AND ANALYSIS

Two independent review authors extracted data and assessed trial quality and risk of bias. We planned to use dichotomous data to calculate risk ratio and number needed to treat for one additional event, using standard methods. We assessed the evidence using GRADE (Grading of Recommendations Assessment, Development and Evaluation) and created a 'Summary of findings' table.

MAIN RESULTS

Two studies tested gabapentin to treat fibromyalgia pain. One was identified in previous versions of the review and is included here. We identified another study as a conference abstract, with insufficient detail to determine eligibility for inclusion; it is awaiting assessment. The one included study of 150 participants was a 12-week, multi-centre, randomised, double-blind, placebo-controlled, parallel-group study using last-observation-carried-forward imputation for withdrawals. The maximum dose was 2400 mg daily. The overall risk of bias was low, except for attrition bias.At the end of the trial, the outcome of 50% reduction in pain over baseline was not reported. The outcome of 30% or greater reduction in pain over baseline was achieved by 38/75 participants (49%) with gabapentin compared with 23/75 (31%) with placebo (very low quality). A patient global impression of change any category of "better" was achieved by 68/75 (91%) with gabapentin and 35/75 (47%) with placebo (very low quality).Nineteen participants discontinued the study because of adverse events: 12 in the gabapentin group (16%) and 7 in the placebo group (9%) (very low quality). The number of serious adverse events were not reported, and no deaths were reported (very low quality).

AUTHORS' CONCLUSIONS

We have only very low quality evidence and are very uncertain about estimates of benefit and harm because of a small amount of data from a single trial. There is insufficient evidence to support or refute the suggestion that gabapentin reduces pain in fibromyalgia.

Stress, Inflammation and Pain: A Potential Role for Monocytes in Fibromyalgia-related Symptom Severity

The possibility that immunological changes might contribute to symptom severity in fibromyalgia (FM) prompted this proof-of-concept study to determine whether differences in monocyte subpopulations might be present in persons with FM compared with healthy controls. Relationships were assessed by comparing specific symptoms in those with FM (n = 20) and patterns of monocyte subpopulations with healthy age-matched and gender-matched controls (n = 20). Within the same time frame, all participants provided a blood sample and completed measures related to pain, fatigue, sleep disturbances, perceived stress, positive and negative affect and depressed mood (and the Fibromyalgia Impact Questionnaire for those with FM). Monocyte subpopulations were assessed using flow cytometry. No differences were observed in total percentages of circulating monocytes between the groups; however, pain was inversely correlated with percentages of circulating classical (r = -0.568, p = 0.011) and intermediate (r = -0.511, p = 0.025) monocytes in the FM group. Stress and pain were highly correlated (r = 0.608, p = 0.004) in the FM group. The emerging pattern of changes in the percentages of circulating monocyte subpopulations concomitant with higher ratings of perceived pain and the correlation between stress and pain found in the FM group warrant further investigation. Copyright © 2015 John Wiley & Sons, Ltd.

[Treatment of fibromyalgia syndrome with gamma-hydroxybutyrate : A randomized controlled study]

BACKGROUND

The etiology of fibromyalgia syndrome is not yet fully understood. Current hypotheses suggest a potential role of gamma-hydroxybutyrate (GHB) in influencing endocrinological abnormalities in patients with fibromyalgia.

OBJECTIVE

The aim of the study was to investigate whether low dose GHB as a growth-hormone releasing substance reduces pain intensity and improves depressive mood, physical impairment and sleep quality in outpatients with fibromyalgia. Additionally, adverse events were recorded.

MATERIAL AND METHODS

The pilot study was conducted in the outpatient clinic for pain at the clinic for anesthesiology and surgical intensive care of the Charité Universitätsmedizin Berlin. In the study 25 female patients with fibromyalgia according to the criteria of the American College of Rheumatology were randomized into 2 groups. Over 15 weeks patients of the intervention group received 25 mg/kg body weight oral GHB before going to bed and were compared with a placebo control group. In addition, all patients participated in operant behavioral pain treatment in a group setting. Dependent variables were pain intensity, depressive mood, physical impairment and quality of sleep.

RESULTS

There were no group differences in the course of pain intensity (p = 0.61), depressive mood (p = 0.16), physical impairment (p = 0.25) and quality of sleep (p = 0.44); however, all symptoms improved across the groups from pretherapy to posttherapy. Low dose GHB did not increase growth hormone blood concentrations. The number of adverse events that were reported more than two times was similar in both groups.

DISCUSSION

Administration of low dose GHB did not yield clinical improvements in female outpatients with fibromyalgia. General improvement in the course of treatment may have resulted from operant behavioral pain therapy. Future studies on GHB should control hypothetical risk factors for identification of non-responders.

Pregabalin for pain in fibromyalgia in adults

BACKGROUND

This review updates part of an earlier Cochrane review on 'Pregabalin for acute and chronic pain in adults' (Moore 2009), and considers only fibromyalgia pain.Antiepileptic drugs have been used in pain management since the 1960s. Pregabalin is an antiepileptic drug also used in management of chronic pain conditions, including fibromyalgia. Pain response with pregabalin is associated with major benefits for other symptoms, and improved quality of life and function in people with chronic painful conditions.

OBJECTIVES

To assess the analgesic efficacy and adverse events of pregabalin for pain in fibromyalgia in adults, compared with placebo or any active comparator.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and EMBASE for randomised controlled trials from inception to May 2009 for the original review and to 16 March 2016 for this update. We also searched the reference lists of retrieved studies and reviews, and online clinical trial registries.

SELECTION CRITERIA

We included randomised, double-blind trials of eight weeks' duration or longer, comparing pregabalin with placebo or another active treatment for relief of pain in fibromyalgia, and reporting on the analgesic effect of pregabalin, with subjective pain assessment by the participant.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed trial quality and potential bias. Primary outcomes were participants with moderate pain relief (at least 30% pain relief over baseline or much or very much improved on Patient Global Impression of Change scale (PGIC)) or substantial pain relief (at least 50% pain relief over baseline or very much improved on PGIC). Where pooled analysis was possible, we used dichotomous data to calculate risk ratio and number needed to treat (NNT), using standard methods. We assessed the quality of the evidence using GRADE (Grading of Recommendations Assessment, Development and Evaluation) and created 'Summary of findings' tables.

MAIN RESULTS

Our searches identified two new published studies with classic design, and one new published study with an enriched enrolment randomised withdrawal (EERW) design.We included eight studies. Five (3283 participants) had a classic design in which participants were randomised at the start of the study to pregabalin (150, 300, 450, or 600 mg daily) or placebo, with assessment after 8 to 13 weeks of stable treatment. No studies included active comparators. Studies had low risk of bias, except that the last observation carried forward (LOCF) imputation method used in analyses of the primary outcomes could overestimate treatment effect.Pregabalin increased the number of participants experiencing substantial benefit (at least 50% pain intensity reduction after 12 or 13 weeks' stable treatment (450 mg: RR 1.8, 95% CI 1.4 to 2.1, 1874 participants, 5 studies, high quality evidence)). Substantial benefit with pregabalin 300 to 600 mg was experienced by about 14% of participants with placebo, but about 9% more with pregabalin 300 to 600 mg (22% to 24%) (high quality evidence). Pregabalin increased the number of participants experiencing moderate benefit (at least 30% pain intensity reduction after 12 or 13 weeks' stable treatment) (450 mg: RR 1.5, 95% CI (1.3 to 1.7), 1874 participants, 5 studies, high quality evidence). Moderate benefit with pregabalin 300 to 600 mg was experienced by about 28% of participants with placebo, but about 11% more with pregabalin 300 to 600 mg (39% to 43%) (high quality evidence). A similar magnitude of effect was found using PGIC of 'very much improved' and 'much or very much improved'. NNTs for these outcomes ranged between 7 and 14 (high quality evidence).A small study (177 participants) compared nightly with twice-daily pregabalin, and concluded there was no difference in effect.Two studies (1492 participants began initial dose titration, 687 participants randomised) had an EERW design in which those with good pain relief after titration were randomised, double blind, to continuing the effective dose (300 to 600 mg pregabalin daily) or a short down-titration to placebo for 13 or 26 weeks. We calculated the outcome of maintained therapeutic response (MTR) without withdrawal, equivalent to a moderate benefit. Of those randomised, 40% had MTR with pregabalin and 20% with placebo (high quality evidence). The NNT was 5, but normalised to the starting population tested it was 12. About 10% of the initial population would have achieved the MTR outcome, similar to the result from studies of classic design. MTR had no imputation concerns.The majority (70% to 90%) of participants in all treatment groups experienced adverse events. Specific adverse events were more common with pregabalin than placebo, in particular dizziness, somnolence, weight gain, and peripheral oedema, with number needed to harm of 3.7, 7.4, 18, and 19 respectively for all doses combined (high quality evidence). Serious adverse events did not differ between active treatment groups and placebo (very low quality evidence). Withdrawals for any reason were more common with pregabalin than placebo only with the 600 mg dose in studies of classic design. Withdrawals due to adverse events were about 10% higher with pregabalin than placebo, but withdrawals due to lack of efficacy were about 6% lower (high quality evidence).

AUTHORS' CONCLUSIONS

Pregabalin 300 to 600 mg produces a major reduction in pain intensity over 12 to 26 weeks with tolerable adverse events for a small proportion of people (about 10% more than placebo) with moderate or severe pain due to fibromyalgia. The degree of pain relief is known to be accompanied by improvements in other symptoms, quality of life, and function. These results are similar to other effective medicines in fibromyalgia (milnacipran, duloxetine).

Oxycodone for pain in fibromyalgia in adults

BACKGROUND

This review replaces part of an earlier review that evaluated oxycodone for both neuropathic pain and fibromyalgia, which has now been split into separate reviews for the two conditions. This review will consider pain in fibromyalgia only.Opioid drugs are commonly used to treat fibromyalgia, but they may not be beneficial for people with this condition. Most reviews have examined all opioids together. This review sought evidence specifically for oxycodone, at any dose, and by any route of administration.

OBJECTIVES

To assess the analgesic efficacy and adverse events of oxycodone for treating pain in fibromyalgia in adults.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and EMBASE for randomised controlled trials from inception to 25 July 2016. We also searched the reference lists of retrieved studies and reviews, and searched online clinical trial registries.

SELECTION CRITERIA

We planned to include randomised, double-blind trials of eight weeks' duration or longer, comparing oxycodone (alone or in fixed-dose combination with naloxone) with placebo or another active treatment. We did not include observational studies.

DATA COLLECTION AND ANALYSIS

The plan was for two independent review authors to extract data and assess trial quality and potential bias. Where pooled analysis was possible, we planned to use dichotomous data to calculate risk ratio and numbers needed to treat for one additional event, using standard methods.

MAIN RESULTS

No study satisfied the inclusion criteria. Effects of interventions were not assessed as there were no included studies. We have only very low quality evidence and are very uncertain about estimates of benefit and harm.

AUTHORS' CONCLUSIONS

There is no randomised trial evidence to support or refute the suggestion that oxycodone, alone or in combination with naloxone, reduces pain in fibromyalgia.

Cannabinoids for fibromyalgia

BACKGROUND

This review is one of a series on drugs used to treat fibromyalgia. Fibromyalgia is a clinically well-defined chronic condition of unknown aetiology characterised by chronic widespread pain that often co-exists with sleep problems and fatigue affecting approximately 2% of the general population. People often report high disability levels and poor health-related quality of life (HRQoL). Drug therapy focuses on reducing key symptoms and disability, and improving HRQoL. Cannabis has been used for millennia to reduce pain and other somatic and psychological symptoms.

OBJECTIVES

To assess the efficacy, tolerability and safety of cannabinoids for fibromyalgia symptoms in adults.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE to April 2016, together with reference lists of retrieved papers and reviews, three clinical trial registries, and contact with trial authors.

SELECTION CRITERIA

We selected randomised controlled trials of at least four weeks' duration of any formulation of cannabis products used for the treatment of adults with fibromyalgia.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted the data of all included studies and assessed risk of bias. We resolved discrepancies by discussion. We performed analysis using three tiers of evidence. First tier evidence was derived from data meeting current best standards and subject to minimal risk of bias (outcome equivalent to substantial pain intensity reduction, intention-to-treat analysis without imputation for drop-outs; at least 200 participants in the comparison, eight to 12 weeks' duration, parallel design), second tier evidence from data that did not meet one or more of these criteria and were considered at some risk of bias but with adequate numbers (i.e. data from at least 200 participants) in the comparison, and third tier evidence from data involving small numbers of participants that were considered very likely to be biased or used outcomes of limited clinical utility, or both. We assessed the evidence using GRADE (Grading of Recommendations Assessment, Development and Evaluation).

MAIN RESULTS

We included two studies with 72 participants. Overall, the two studies were at moderate risk of bias. The evidence was derived from group mean data and completer analysis (very low quality evidence overall). We rated the quality of all outcomes according to GRADE as very low due to indirectness, imprecision and potential reporting bias.The primary outcomes in our review were participant-reported pain relief of 50% or greater, Patient Global Impression of Change (PGIC) much or very much improved, withdrawal due to adverse events (tolerability) and serious adverse events (safety). Nabilone was compared to placebo and to amitriptyline in one study each. Study sizes were 32 and 40 participants. One study used a cross-over design and one used a parallel group design; study duration was four or six weeks. Both studies used nabilone, a synthetic cannabinoid, with a bedtime dosage of 1 mg/day. No study reported the proportion of participants experiencing at least 30% or 50% pain relief or who were very much improved. No study provided first or second tier (high to moderate quality) evidence for an outcome of efficacy, tolerability and safety. Third tier (very low quality) evidence indicated greater reduction of pain and limitations of HRQoL compared to placebo in one study. There were no significant differences to placebo noted for fatigue and depression (very low quality evidence). Third tier evidence indicated better effects of nabilone on sleep than amitriptyline (very low quality evidence). There were no significant differences between the two drugs noted for pain, mood and HRQoL (very low quality evidence). More participants dropped out due to adverse events in the nabilone groups (4/52 participants) than in the control groups (1/20 in placebo and 0/32 in amitriptyline group). The most frequent adverse events were dizziness, nausea, dry mouth and drowsiness (six participants with nabilone). Neither study reported serious adverse events during the period of both studies. We planned to create a GRADE 'Summary of findings' table, but due to the scarcity of data we were unable to do this. We found no relevant study with herbal cannabis, plant-based cannabinoids or synthetic cannabinoids other than nabilone in fibromyalgia.

AUTHORS' CONCLUSIONS

We found no convincing, unbiased, high quality evidence suggesting that nabilone is of value in treating people with fibromyalgia. The tolerability of nabilone was low in people with fibromyalgia.

Antipsychotics for fibromyalgia in adults

BACKGROUND

This review is one of a series on drugs used to treat fibromyalgia. Fibromyalgia is a clinically well-defined chronic condition of unknown aetiology characterised by chronic widespread pain that often co-exists with sleep problems and fatigue. It affects approximately 2% of the general population. Up to 70% of patients with fibromyalgia meet the criteria for a depressive or anxiety disorder. People often report high disability levels and poor health-related quality of life. Drug therapy focuses on reducing key symptoms and disability, and improving health-related quality of life. Antipsychotics might reduce fibromyalgia and associated mental health symptoms.

OBJECTIVES

To assess the efficacy, tolerability and safety of antipsychotics in fibromyalgia in adults.

SEARCH METHODS

We searched CENTRAL (2016, Issue 4), MEDLINE and EMBASE to 20 May 2016, together with reference lists of retrieved papers and reviews and two clinical trial registries. We also contacted trial authors.

SELECTION CRITERIA

We selected controlled trials of at least four weeks duration of any formulation of antipsychotics used for the treatment of fibromyalgia in adults.

DATA COLLECTION AND ANALYSIS

We extracted the data from all included studies and two review authors independently assessed study risks of bias. We resolved discrepancies by discussion. We performed analysis using three tiers of evidence. We derived first tier evidence from data meeting current best standards and subject to minimal risk of bias (outcome equivalent to substantial pain intensity reduction, intention-to-treat analysis without imputation for drop-outs, at least 200 participants in the comparison, eight to 12 weeks duration, parallel design), second tier evidence from data that failed to meet one or more of these criteria and that we considered at some risk of bias but with adequate numbers in the comparison, and third tier evidence from data involving small numbers of participants that we considered very likely to be biased or used outcomes of limited clinical utility, or both. We rated the quality of evidence using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

We included a total of four studies with 296 participants.Three studies with 206 participants compared quetiapine, an atypical (second-generation) antipsychotic, with placebo. One study used a cross-over design and two studies a parallel-group design. Study duration was eight or 12 weeks. Quetiapine was used in all studies with a bedtime dosage between 50 and 300 mg/day. All studies had one or more sources of potential major bias and we judged them to be at moderate risk of bias overall. The primary outcomes in this review were participant-reported pain relief of 50% or greater, Patient Global Impression of Change (PGIC) much or very much improved, withdrawal due to adverse events (tolerability) and serious adverse events (safety).Second tier evidence indicated that quetiapine was not statistically superior to placebo in the number of participants with a 50% or more pain reduction (very low quality evidence). No study reported data on PGIC. A greater proportion of participants on quetiapine reported a 30% or more pain reduction (risk difference (RD) 0.12, 95% confidence interval (CI) 0.00 to 0.23; number needed to treat for an additional benefit (NNTB) 8, 95% CI 5 to 100) (very low quality evidence). A greater proportion of participants on quetiapine reported a clinically relevant improvement of health-related quality of life compared to placebo ( RD 0.18, 95% CI 0.05 to 0.31; NNTB 5, 95% CI 3 to 20) (very low quality evidence). Quetiapine was statistically superior to placebo in reducing sleep problems (standardised mean difference (SMD) -0.67, 95% CI -1.10 to -0.23), depression (SMD -0.39, 95% CI -0.74 to -0.04) and anxiety (SMD -0.40, 95% CI -0.69 to -0.11) (very low quality evidence). Quetiapine was statistically superior to placebo in reducing the risk of withdrawing from the study due to a lack of efficacy (RD -0.14, 95% CI -0.23 to -0.05) (very low quality evidence). There was no statistically significant difference between quetiapine and placebo in the proportion of participants withdrawing due to adverse events (tolerability) (very low quality evidence), in the frequency of serious adverse events (safety) (very low quality evidence) and in the proportion of participants reporting dizziness and somnolence as an adverse event (very low quality evidence). In more participants in the quetiapine group a substantial weight gain was noted (RD 0.08, 95% CI 0.02 to 0.15; number needed to treat for an additional harm (NNTH) 12, 95% CI 6 to 50) (very low quality evidence). We downgraded the quality of evidence by three levels to a very low quality rating because of limitations of study design, indirectness (patients with major medical diseases and mental disorders were excluded) and imprecision (fewer than 400 patients were analysed).One parallel design study with 90 participants compared quetiapine (50 to 300 mg/day flexible at bedtime) to amitriptyline (10 to 75 mg/day flexible at bedtime). The study had three major risks of bias and we judged it to be at moderate risk of bias overall. We downgraded the quality of evidence by two levels to a low quality rating because of indirectness (patients with major medical diseases and mental disorders were excluded) and imprecision (fewer than 400 patients were analysed). Third tier evidence indicated no statistically significant differences between the two drugs. Both drugs did not statistically significantly differ in the reduction of average scores for pain, fatigue, sleep problems, depression, anxiety and for limitations of health-related quality of life and in the proportion of participants reporting dizziness, somnolence and weight gain as a side effect (low quality evidence). Compared to amitriptyline, more participants left the study due to adverse events (low quality evidence). No serious adverse events were reported (low quality evidence).We found no relevant study with other antipsychotics than quetiapine in fibromyalgia.

AUTHORS' CONCLUSIONS

Very low quality evidence suggests that quetiapine may be considered for a time-limited trial (4 to 12 weeks) to reduce pain, sleep problems, depression and anxiety in fibromyalgia patients with major depression. Potential side effects such as weight gain should be balanced against the potential benefits in shared decision making with the patient.

[Fibromyalgia syndrome: A disease of the small nerve fibers?]

Fibromyalgia syndrome (FMS) is characterized by chronic widespread pain and additional associated symptoms, such as fatigue, sleep disturbances and depressive moods. The pathophysiology of pain in FMS is unclear. In recent years, an involvement of the thinly myelinated A-delta and the unmyelinated C-nerve fibers has been reported in FMS patients. Independent research groups published consistent objective and multidimensional findings of damage to these small nerve fibers, such as disturbances of fiber function, electrical properties and morphological changes. All these alterations are not specific for FMS; however, they were described for the first time in subgroups of FMS patients. While the reasons for this small fiber pathology and its contribution to FMS pain are still unclear, a new research field has now been opened that will focus on uncovering the underlying pathophysiology. This review article summarizes these new findings and discusses the significance for the understanding of FMS.

Programmed symptoms: disparate effects united by purpose

Central sensitivity syndromes (CSS) share features of similar multiple symptoms, virtually unknown mechanisms and lack of effective treatments. The CSS nomenclature was chosen over alternatives because it focused on a putative physiological mechanism of central sensitization common to disorders such as fibromyalgia, irritable bowel syndrome, vulvodynia and temporomandibular disorder. Increasing evidence from multiple biological systems suggests a further development. In this new model central sensitization is part of a ensemble that includes also the symptoms of widespread pain, fatigue, unrefreshing sleep and dyscognition. The main feature is an intrinsic program that produces this ensemble to guide behavior to restore normal function in conditions that threaten survival. The well known “illness response” is a classic example that is triggered in response to the specific threat of viral infection. The major leap for this model in the context of CSS is that the symptom complex is not a reactive result of pathology, but a purposeful feeling state enlisted to combat pathology. Once triggered, this state is produced by potential mechanisms that likely include contributions of the peripheral and central immune systems, as well as stress response systems such as the autonomic system and the hypothalamic–pituitary–adrenal (HPA) axis. These act in concert to alter behavior in a beneficial direction. This concept explains similar symptoms for many triggering conditions, the poorly understood pathology, and the resistance to treatment.

Exploring Genetic Susceptibility to Fibromyalgia

Fibromyalgia (FM) affects 1% to 5% of the population, and approximately 90% of the affected individuals are women. FM patients experience impaired quality of life and the disorder places a considerable economic burden on the medical care system. With the recognition of FM as a major health problem, many recent studies have evaluated the pathophysiology of FM. Although the etiology of FM remains unknown, it is thought to involve some combination of genetic susceptibility and environmental exposure that triggers further alterations in gene expression. Because FM shows marked familial aggregation, most previous research has focused on genetic predisposition to FM and has revealed associations between genetic factors and the development of FM, including specific gene polymorphisms involved in the serotonergic, dopaminergic, and catecholaminergic pathways. The aim of this review was to discuss the current evidence regarding genetic factors that may play a role in the development and symptom severity of FM.

Fibromyalgia

Fibromyalgia is a common illness characterized by chronic widespread pain, sleep problems (including unrefreshing sleep), physical exhaustion and cognitive difficulties. The definition, pathogenesis and treatment are controversial, and some even contest the existence of this disorder. In 1990, the American College of Rheumatology (ACR) defined classification criteria that required multiple tender points (areas of tenderness occurring in muscles and muscle-tendon junctions) and chronic widespread pain. In 2010, the ACR preliminary diagnostic criteria excluded tender points, allowed less extensive pain and placed reliance on patient-reported somatic symptoms and cognitive difficulties. Fibromyalgia occurs in all populations worldwide, and symptom prevalence ranges between 2% and 4% in the general population. The prevalence of people who are actually diagnosed with fibromyalgia ('administrative prevalence') is much lower. A model of fibromyalgia pathogenesis has been suggested in which biological and psychosocial variables interact to influence the predisposition, triggering and aggravation of a chronic disease, but the details are unclear. Diagnosis requires the history of a typical cluster of symptoms and the exclusion of a somatic disease that sufficiently explains the symptoms by medical examination. Current evidence-based guidelines emphasize the value of multimodal treatments, which encompass both non-pharmacological and selected pharmacological treatments tailored to individual symptoms, including pain, fatigue, sleep problems and mood problems. For an illustrated summary of this Primer, visit: http://go.nature.com/LIBdDX.

Selective serotonin reuptake inhibitors for fibromyalgia syndrome

BACKGROUND

Fibromyalgia is a clinically well-defined chronic condition with a biopsychosocial aetiology. Fibromyalgia is characterized by chronic widespread musculoskeletal pain, sleep problems, cognitive dysfunction, and fatigue. Patients often report high disability levels and poor quality of life. Since there is no specific treatment that alters the pathogenesis of fibromyalgia, drug therapy focuses on pain reduction and improvement of other aversive symptoms.

OBJECTIVES

The objective was to assess the benefits and harms of selective serotonin reuptake inhibitors (SSRIs) in the treatment of fibromyalgia.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2014, Issue 5), MEDLINE (1966 to June 2014), EMBASE (1946 to June 2014), and the reference lists of reviewed articles.

SELECTION CRITERIA

We selected all randomized, double-blind trials of SSRIs used for the treatment of fibromyalgia symptoms in adult participants. We considered the following SSRIs in this review: citalopram, fluoxetine, escitalopram, fluvoxamine, paroxetine, and sertraline.

DATA COLLECTION AND ANALYSIS

Three authors extracted the data of all included studies and assessed the risks of bias of the studies. We resolved discrepancies by discussion.

MAIN RESULTS

The quality of evidence was very low for each outcome. We downgraded the quality of evidence to very low due to concerns about risk of bias and studies with few participants. We included seven placebo-controlled studies, two with citalopram, three with fluoxetine and two with paroxetine, with a median study duration of eight weeks (4 to 16 weeks) and 383 participants, who were pooled together.All studies had one or more sources of potential major bias. There was a small (10%) difference in patients who reported a 30% pain reduction between SSRIs (56/172 (32.6%)) and placebo (39/171 (22.8%)) risk difference (RD) 0.10, 95% confidence interval (CI) 0.01 to 0.20; number needed to treat for an additional beneficial outcome (NNTB) 10, 95% CI 5 to 100; and in global improvement (proportion of patients who reported to be much or very much improved: 50/168 (29.8%) of patients with SSRIs and 26/162 (16.0%) of patients with placebo) RD 0.14, 95% CI 0.06 to 0.23; NNTB 7, 95% CI 4 to 17.SSRIs did not statistically, or clinically, significantly reduce fatigue: standard mean difference (SMD) -0.26, 95% CI -0.55 to 0.03; 7.0% absolute improvement on a 0 to 10 scale, 95% CI 14.6% relative improvement to 0.8% relative deterioration; nor sleep problems: SMD 0.03, 95 % CI -0.26 to 0.31; 0.8 % absolute deterioration on a 0 to 100 scale, 95% CI 8.3% relative deterioration to 6.9% relative improvement.SSRIs were superior to placebo in the reduction of depression: SMD -0.39, 95% CI -0.65 to -0.14; 7.6% absolute improvement on a 0 to 10 scale, 95% CI 2.7% to 13.8% relative improvement; NNTB 13, 95% CI 7 to 37. The dropout rate due to adverse events was not higher with SSRI use than with placebo use (23/146 (15.8%) of patients with SSRIs and 14/138 (10.1%) of patients with placebo) RD 0.04, 95% CI -0.06 to 0.14. There was no statistically or clinically significant difference in serious adverse events with SSRI use and placebo use (3/84 (3.6%) in patients with SSRIs and 4/84 (4.8%) and patients with placebo) RD -0.01, 95% CI -0.07 to 0.05.

AUTHORS' CONCLUSIONS

There is no unbiased evidence that SSRIs are superior to placebo in treating the key symptoms of fibromyalgia, namely pain, fatigue and sleep problems. SSRIs might be considered for treating depression in people with fibromyalgia. The black box warning for increased suicidal tendency in young adults aged 18 to 24, with major depressive disorder, who have taken SSRIs, should be considered when appropriate.

Discerning primary and secondary factors responsible for clinical fatigue in multisystem diseases

Fatigue is a common symptom of numerous acute and chronic diseases, including myalgic encephalomyelitis/chronic fatigue syndrome, multiple sclerosis, heart failure, cancer, and many others. In these multi-system diseases the physiological determinants of enhanced fatigue encompass a combination of metabolic, neurological, and myofibrillar adaptations. Previous research studies have focused on adaptations specific to skeletal muscle and their role in fatigue. However, most have neglected the contribution of physical inactivity in assessing disease syndromes, which, through deconditioning, likely contributes to symptomatic fatigue. In this commentary, we briefly review disease-related muscle phenotypes in the context of whether they relate to the primary disease or whether they develop secondary to reduced physical activity. Knowledge of the etiology of the skeletal muscle adaptations in these conditions and their contribution to fatigue symptoms is important for understanding the utility of exercise rehabilitation as an intervention to alleviate the physiological precipitants of fatigue.

An insight into the gastrointestinal component of fibromyalgia: clinical manifestations and potential underlying mechanisms

Fibromyalgia syndrome is characterized by chronic generalized pain accompanied by a broad symptomatologic spectrum. Besides chronic fatigue, sleep disturbances, headaches and cognitive dysfunction that are extensively described in the literature, a considerable proportion of patients with fibromyalgia experience gastrointestinal symptoms that are commonly overlooked in the studies that are not specifically dedicated to evaluate these manifestations. Nevertheless, various attempts were undertaken to explore the gastrointestinal dimension of fibromyalgia. Several studies have demonstrated an elevated comorbidity of irritable bowel syndrome (IBS) among patients with fibromyalgia. Other studies have investigated the frequency of presentation of gastrointestinal symptoms in fibromyalgia in a nonspecific approach describing several gastrointestinal complaints frequently reported by these patients such as abdominal pain, dyspepsia and bowel changes, among others. Several underlying mechanisms that require further investigation could serve as potential explanatory hypotheses for the appearance of such manifestations. These include sensitivity to dietary constituents such as gluten, lactose or FODMAPs or alterations in the brain-gut axis as a result of small intestinal bacterial overgrowth or subclinical enteric infections such as giardiasis. The gastrointestinal component of fibromyalgia constitutes a relevant element of the multidisciplinary pathophysiologic mechanisms underlying fibromyalgia that need to be unveiled, as this would contribute to the adequate designation of relevant treatment alternatives corresponding to these manifestations.

Childhood stressors in the development of fatigue syndromes: a review of the past 20 years of research

BACKGROUND

Chronic fatigue syndrome (CFS) and fibromyalgia (FM) are both highly prevalent conditions associated with extreme disability and with the development of co-morbid psychiatric disorders, such as depression and anxiety. Childhood stressors have been shown to induce persistent changes in the function of biological systems potentially relevant to the pathogenesis of both CFS and FM, such as the inflammatory system and the hypothalamic-pituitary-adrenal (HPA) axis. In this review, we examined whether multiple forms of childhood stressors are contributing factors to the development of these disorders, and of the associated psychiatric symptoms.

METHOD

Using PubMed, we identified 31 papers relevant to this narrative review. We included cohort studies and case-control studies, without any exclusion in terms of age and gender. No study characteristics or publication date restrictions were imposed.

RESULTS

Most studies across the literature consistently show that there is a strong association between experiences of childhood stressors and the presence of CFS and FM, with rates of CFS/FM being two- to three-fold higher in exposed than in unexposed subjects. We also found evidence for an increased risk for the development of additional symptoms, such as depression, anxiety and pain, in individuals with CFS and FM with a previous history of childhood stressors, compared with individuals with CFS/FM and no such history.

CONCLUSIONS

Our review confirms that exposure to childhood stressors is associated with the subsequent development of fatigue syndromes such as CFS and FM, and related symptoms. Further studies are needed to identify the mechanisms underlying these associations.

Fibromyalgia syndrome: a somatoform disorder?

BACKGROUND AND OBJECTIVE

Whether fibromyalgia syndrome (FMS) can be classified as a somatoform disorder is under debate.

DATABASES AND DATA TREATMENT

Literature searches on the classification of FMS as a somatoform disorder were performed in Medline and in evidence-based guideline databases.

RESULTS

A somatoform disorder is defined by medically unexplained somatic symptoms that persist for at least 6 months and lead to a significant impairment of the ability to function in everyday life. The nature and extent of the symptoms or the distress and pre-occupation of the patient cannot be explained fully by a general medical condition or by the direct effect of a substance, and are not attributable to another mental disorder. Emotional and psychosocial conflicts play a major role in the onset, severity, exacerbation or maintenance of the physical symptoms. There is disagreement in the FMS research community on the existence of somatic factors sufficiently explaining FMS symptoms. Psychosocial factors play a major role in the onset, exacerbation or maintenance of FMS symptoms in the majority of patients. A biopsychosocial model of interacting biological and psychosocial factors in the predisposition, onset and maintenance of FMS symptoms is more appropriate than the dichotomy between a somatic disease and a mental (somatoform) disorder.

CONCLUSIONS

The clinical features of FMS and persistent somatoform pain disorder or somatization disorder according to the International Classification of Diseases (ICD)-10 overlap in individuals with chronic widespread pain without specific somatic disease factors. FMS is not synonymous with somatoform disorder.

Classification and clinical diagnosis of fibromyalgia syndrome: recommendations of recent evidence-based interdisciplinary guidelines

Objectives. Fibromyalgia syndrome (FMS), characterized by subjective complaints without physical or biomarker abnormality, courts controversy. Recommendations in recent guidelines addressing classification and diagnosis were examined for consistencies or differences. Methods. Systematic searches from January 2008 to February 2013 of the US-American National Guideline Clearing House, the Scottish Intercollegiate Guidelines Network, Guidelines International Network, and Medline for evidence-based guidelines for the management of FMS were conducted. Results. Three evidence-based interdisciplinary guidelines, independently developed in Canada, Germany, and Israel, recommended that FMS can be clinically diagnosed by a typical cluster of symptoms following a defined evaluation including history, physical examination, and selected laboratory tests, to exclude another somatic disease. Specialist referral is only recommended when some other physical or mental illness is reasonably suspected. The diagnosis can be based on the (modified) preliminary American College of Rheumatology (ACR) 2010 diagnostic criteria. Discussion. Guidelines from three continents showed remarkable consistency regarding the clinical concept of FMS, acknowledging that FMS is neither a distinct rheumatic nor mental disorder, but rather a cluster of symptoms, not explained by another somatic disease. While FMS remains an integral part of rheumatology, it is not an exclusive rheumatic condition and spans a broad range of medical disciplines.

Anticonvulsants for fibromyalgia

BACKGROUND

Fibromyalgia (FM) is a clinically well-defined chronic condition of unknown aetiology characterised by chronic widespread pain that often co-exists with sleep problems and fatigue. People often report high disability levels and poor health-related quality of life (HRQoL). Drug therapy focuses on reducing key symptoms and disability, and improving HRQoL. Anticonvulsants (antiepileptic drugs) are drugs frequently used for the treatment of chronic pain syndromes.

OBJECTIVES

To assess the benefits and harms of anticonvulsants for treating FM symptoms.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 8, 2013), MEDLINE (1966 to August 2013), PsycINFO (1966 to August 2013), SCOPUS (1980 to August 2013) and the reference lists of reviewed articles for published studies and www.clinicaltrials.gov (to August 2013) for unpublished trials.

SELECTION CRITERIA

We selected randomised controlled trials of any formulation of anticonvulsants used for the treatment of people with FM of any age.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted the data of all included studies and assessed the risks of bias of the studies. We resolved discrepancies by discussion.

MAIN RESULTS

We included eight studies: five with pregabalin and one study each with gabapentin, lacosamide and levetiracetam. A total of 2480 people were included into anticonvulsants groups and 1099 people in placebo groups. The median therapy phase of the studies was 13 weeks. The amount and quality of evidence were insufficient to draw definite conclusions on the efficacy and safety of gabapentin, lacosamide and levetiracetam in FM. The amount and quality of evidence was sufficient to draw definite conclusions on the efficacy and safety of pregabalin in FM. Therefore, we focused on our interpretation of the evidence for pregabalin due to our greater certainty about its effects and its greater relevance to clinical practice. All pregabalin studies had a low risk of bias. Reporting a 50% or greater reduction in pain was more frequent with pregabalin use than with a placebo (risk ratio (RR) 1.59; 95% confidence interval (CI) 1.33 to 1.90; number needed to treat for an additional beneficial outcome (NNTB) 12; 95% CI 9 to 21). The number of people who reported being 'much' or 'very much' improved was higher with pregabalin than with placebo (RR 1.38; 95% CI 1.23 to 1.55; NNTB 9; 95% CI 7 to 15). Pregabalin did not substantially reduce fatigue (SMD -0.17; 95% CI -0.25 to -0.09; 2.7% absolute improvement on a 1 to 50 scale) compared with placebo. Pregabalin had a small benefit over placebo in reducing sleep problems by 6.2% fewer points on a scale of 0 to 100 (standardised mean difference (SMD) -0.35; 95% CI -0.43 to -0.27). The dropout rate due to adverse events was higher with pregabalin use than with placebo use (RR 1.68; 95% CI 1.36 to 2.07; number needed to treat for an additional harmful outcome (NNTH) 13; 95% CI 9 to 23). There was no significant difference in serious adverse events between pregabalin and placebo use (RR 1.03; 95% CI 0.71 to 1.49). Dizziness was reported as an adverse event more frequently with pregabalin use than with placebo use (RR 3.77; 95% CI 3.06 to 4.63; NNTH 4; 95% CI 3 to 5).

AUTHORS' CONCLUSIONS

The anticonvulsant, pregabalin, demonstrated a small benefit over placebo in reducing pain and sleep problems. Pregabalin use was shown not to substantially reduce fatigue compared with placebo. Study dropout rates due to adverse events were higher with pregabalin use compared with placebo. Dizziness was a particularly frequent adverse event seen with pregabalin use. At the time of writing this review, pregabalin is the only anticonvulsant drug approved for treating FM in the US and in 25 other non-European countries. However, pregabalin has not been approved for treating FM in Europe. The amount and quality of evidence were insufficient to draw definite conclusions on the efficacy and safety of gabapentin, lacosamide and levetiracetam in FM.

Cognitive behavioural therapies for fibromyalgia

BACKGROUND

Fibromyalgia (FM) is a clinically well-defined chronic condition of unknown aetiology characterized by chronic widespread pain that often co-exists with sleep disturbances, cognitive dysfunction and fatigue. Patients often report high disability levels and negative mood. Psychotherapies focus on reducing key symptoms, improving daily functioning, mood and sense of personal control over pain.

OBJECTIVES

To assess the benefits and harms of cognitive behavioural therapies (CBTs) for treating FM at end of treatment and at long-term (at least six months) follow-up.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 8), MEDLINE (1966 to 28 August 2013), PsycINFO (1966 to 28 August 2013) and SCOPUS (1980 to 28 August 2013). We searched http://www.clinicaltrials.gov (web site of the US National Institutes of Health) and the World Health Organization Clinical Trials Registry Platform (ICTRP) (http://www.who.int/ictrp/en/) for ongoing trials (last search 28 August,2013), and the reference lists of reviewed articles.

SELECTION CRITERIA

We selected randomised controlled trials of CBTs with children, adolescents and adults diagnosed with FM.

DATA COLLECTION AND ANALYSIS

The data of all included studies were extracted and the risks of bias of the studies were assessed independently by two review authors. Discrepancies were resolved by discussion.

MAIN RESULTS

Twenty-three studies with 24 study arms with CBTs were included. A total of 2031 patients were included; 1073 patients in CBT groups and 958 patients in control groups. Only two studies were without any risk of bias. The GRADE quality of evidence of the studies was low. CBTs were superior to controls in reducing pain at end of treatment by 0.5 points on a scale of 0 to 10 (standardised mean difference (SMD) - 0.29; 95% confidence interval (CI) -0.49 to -0.17) and by 0.6 points at long-term follow-up (median 6 months) (SMD -0.40; 95% CI -0.62 to -0.17); in reducing negative mood at end of treatment by 0.7 points on a scale of 0 to 10 (SMD - 0.33; 95% CI -0.49 to -0.17) and by 1.3 points at long-term follow-up (median 6 months) (SMD -0.43; 95% CI -0.75 to -0.11); and in reducing disability at end of treatment by 0.7 points on a scale of 0 to 10 (SMD - 0.30; 95% CI -0.51 to -0.08) and at long-term follow-up (median 6 months) by 1.2 points (SMD -0.52; 95% CI -0.86 to -0.18). There was no statistically significant difference in dropout rates for any reasons between CBTs and controls (risk ratio (RR) 0.94; 95% CI 0.65 to 1.35).

AUTHORS' CONCLUSIONS

CBTs provided a small incremental benefit over control interventions in reducing pain, negative mood and disability at the end of treatment and at long-term follow-up. The dropout rates due to any reason did not differ between CBTs and controls.

[Fibromyalgia syndrome as a psychosomatic disorder - diagnosis and therapy according to current evidence-based guidelines]

OBJECTIVES

The classification and therapy of patients with chronic widespread pain without evidence of somatic factors as an explanation is currently a matter of debate. The diagnostic label "fibromyalgia syndrome"(FMS) has been rejected by some representatives of general and psychosomatic medicine.

METHODS

A summary is given of the main recommendations from current evidence-based guidelines on FMS and nonspecific/functional/somatoform bodily complaints.

RESULTS

The criteria of FMS and of persistent somatoform pain disorder or chronic pain disorder with somatic and psychological factors partly overlap. They include differential clinical characteristics of persons with chronic widespread pain but without sufficiently explaining somatic factors. Not all patients diagnosed with FMS meet the criteria of a persistent somatoform pain disorder. FMS is a functional disorder, in which in most patients psychosocial factors play an important role in both the etiology and course of illness. FMS can be diagnosed by looking at the history of a typical symptom cluster and excluding somatic differential diagnoses (without a tender point examination) using the modified 2010 diagnostic criteria of the American College of Rheumatology. Various levels of severity of FMS can be distinguished from a psychosomatic point of view, ranging from slight (single functional syndrome) to severe (meeting the criteria of multiple functional syndromes) forms of chronic pain disorder with somatic and psychological factors, of persistent somatoform pain disorder or of a somatization disorder. The diagnosis of FMS as a functional syndrome/stress-associated disorder should be explicitly communicated to the patient. A therapy within collaborative care adapted to the severity should be provided. For long-term management, nonpharmacological therapies such as aerobic exercise are recommended. In more severe cases, psychotherapy of comorbid mental disorders should be conducted.

CONCLUSIONS

The coordinated recommendations of both guidelines can synthesize general medical, somatic, and psychosocial perspectives, and can promote graduated care of patients diagnosed with FMS.

Serotonin and noradrenaline reuptake inhibitors (SNRIs) for fibromyalgia syndrome

BACKGROUND

Fibromyalgia syndrome (FMS) is a clinically well-defined chronic condition of unknown etiology characterized by chronic widespread pain that often co-exists with sleep disturbances, cognitive dysfunction and fatigue. Patients often report high disability levels and poor quality of life (QOL). Drug therapy focuses on reducing key symptoms and improving quality of life.

OBJECTIVES

To assess the benefits and harms of serotonin and noradrenaline reuptake inhibitors (SNRIs) compared with placebo for treating FMS symptoms in adults.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), (The Cochrane Library 2012, Issue 9), MEDLINE (1966 to September 2012), EMBASE (1980 to September 2012), www.clinicalstudyresults.org (U.S.-marketed pharmaceuticals) (to September 2012) and www.clinicaltrials.gov (to September 2012) for published and ongoing trials and examined the reference lists of reviewed articles.

SELECTION CRITERIA

We selected randomized, controlled trials of any formulation of SNRIs against placebo for the treatment of FMS in adults.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted the data from the included studies, and assessed the risks of bias of the studies. Discrepancies were resolved by discussion.

MAIN RESULTS

Ten studies were included with a total of 6038 participants. Five studies investigated duloxetine against placebo, and five investigated milnacipran against placebo. A total of 3611 participants were included into duloxetine or milnacipran groups and 2427 participants into placebo groups. The studies had a low risk of bias in general. Duloxetine and milnacipran had a small incremental effect over placebo in reducing pain (standardized mean difference (SMD) -0.23; 95% confidence interval (CI) -0.29 to -0.18; 6.1% relative improvement). One-hundred and ninety-two participants per 1000 on placebo reported an at least 50% pain reduction compared to 280 per 1000 on SNRIs (Risk ratio (RR) 1.49, 95% CI 1.35 to 1.64; number needed to treat to benefit (NNTB) 11, 95% CI 9 to 15). Duloxetine and milnacipran did not reduce fatigue substantially (SMD -0.14; 95% CI -0.19 to -0.08; 2.5% relative improvement; NNTB 17, 95% CI 12 to 29), and did not improve QOL substantially (SMD -0.20; 95% CI -0.25 to -0.14; 4.6% relative improvement; NNTB 12, 95% CI 9 to 17) compared to placebo. There were no statistically significant differences between either duloxetine or milnacipran and placebo in reducing sleep problems (SMD -0.07; 95% CI -0.16 to 0.03; 2.5% relative improvement). One-hundred and seven participants per 1000 on placebo dropped out due to adverse events compared to 196 per 1000 on SNRIs. The dropout rate due to adverse events in the duloxetine and milnacipran groups was statistically significantly higher than in placebo groups (RR 1.83, 95% CI 1.53 to 2.18; number needed to treat to harm (NNTH) 11, 95% CI 9 to 13). There was no statistically significant difference in serious adverse events between either duloxetine or milnacipran and placebo (RR 0.78, 95% CI 0.55 to 1.12).

AUTHORS' CONCLUSIONS

The SNRIs duloxetine and milnacipran provided a small incremental benefit over placebo in reducing pain. The superiority of duloxetine and milnacipran over placebo in reducing fatigue and limitations of QOL was not substantial. Duloxetine and milnacipran were not superior to placebo in reducing sleep problems. The dropout rates due to adverse events were higher for duloxetine and milnacipran than for placebo. The most frequently reported symptoms leading to stopping medication were nausea, dry mouth, constipation, headache, somnolence/dizziness and insomnia. Rare complications of both drugs may include suicidality, liver damage, abnormal bleeding, elevated blood pressure and urinary hesitation.