Pharmacotherapeutic advances in fibromyalgia: what's new on the horizon?

INTRODUCTION: This review delves into Fibromyalgia Syndrome (FMS), a chronic pain condition demanding thorough understanding for precise diagnosis and treatment. Yet, a definitive pharmacological solution for FMS remains elusive. AREAS COVERED: In this article, we systematically analyze various pharmacotherapeutic prospects for FMS treatment, organized into sections based on the stage of drug development and approval. We begin with an overview of FDA-approved drugs, discussing their efficacy in FMS treatment. Next, we delve into other medications currently used for FMS but still undergoing further study, including opioids and muscle relaxants. Further, we evaluate the evidence behind medications that are currently under study, such as cannabinoids and naltrexone. Lastly, we explore new drugs that are in phase II trials. Our research involved a thorough search on PUBMED, Google Scholar, and clinicaltrials.gov. We also discuss the action mechanisms of these drugs and their potential use in specific patient groups. EXPERT OPINION: A focus on symptom-driven, combination therapy is crucial in managing FMS. There is also a need for ongoing research into drugs that target neuroinflammation, immunomodulation, and the endocannabinoid system. Bridging the gap between benchside research and clinical application is challenging, but it holds potential for more targeted and effective treatment strategies.

Environmental factors and fibromyalgia syndrome: a narrative review.

This in-depth review of fibromyalgia (FM), which is a complex condition characterised by chronic pain, fatigue, sleep disturbances, and a spectrum of diagnostically and therapeutically challenging symptoms, underlines the need for a comprehensive and integrated approach that also takes into account the psychological factors affecting patient responses. We focus on the substantial impact that environmental factors (climatic variations, air pollution, electromagnetic field exposure, physical and emotional traumas, dietary patterns, and infections) have on the manifestation and intensity of symptoms, and advocate personalised, holistic treatment of patients' psychological and environmental sensitivities by suggesting the benefits of tailored dietary and stress management. We also call for further research into the complex interplay of environmental, biological and psychological factors influencing FM in order to develop more effective individualised treatments that are capable of enhancing patient care and outcomes.

Fibromyalgia: one year in review 2024.

Fibromyalgia (FM) remains a condition with a pathogenesis that is not completely understood, affecting a significant portion of the global population. This article summarises the main advances in FM during the last year. Even in 2023, research on FM was notably active. From a clinimetric perspective, studies have been conducted to evaluate the possibilities of interchanging the primary indices of disease severity, primarily for studies with substantial case numbers. Regarding FM pathogenesis, ongoing research focuses on small fiber neuropathy: some studies have documented its association with central sensitisation, while others have revealed distinct sensory profiles in patients with FM and small fiber neuropathy compared to those solely with small fiber neuropathy. Dorsal root ganglia seem to play a crucial role in the pathogenesis of FM as they host satellite glial cells, which are targeted by pain-driving immunoglobulin G. These antibodies have been identified in a subset of patients exhibiting high symptom severity. An important study conducted on animal models confirmed the role of neuroinflammation at the level of dorsal root ganglia, in this case mediated by polymorphonuclear neutrophils. Mounting evidence underscores the link between COVID-19 and the persistence of FM symptoms after recovery. In identifying potential biomarkers aiding FM diagnosis, research has also concentrated on studying the expression of specific circulating microRNAs. Recent discoveries have unveiled novel therapeutic strategies for FM, especially focused in non-pharmacological interventions. This includes a focus on non-invasive brain stimulation and exercise programs, all directed towards relieving symptoms and improving functionality in individuals affected by the condition.

Central sensitivity in fibromyalgia: testing a model to explain the role of psychological factors on functioning and quality of life.

OBJECTIVES: Central sensitivity (CS) is defined as an increased responsiveness of nociceptive neurons in the central nervous system to normal or subthreshold inputs. CS has recently been linked to the psychological burden associated with chronic pain, such as fibromyalgia (FM). The primary objective of this study is to investigate the impact of specific psychological constructs on CS in patients with FM. In Study 1, we explore the influence of temperament, personality, childhood trauma, defence mechanisms, and mental pain on CS. In Study 2, our goal is to test the role of the best predictors of CS in influencing quality of life (QoL) and FM functioning through a path analysis model. METHODS: A total of 510 women with FM participated online, completing a self-administered protocol. Data collection took place between April and June of 2023. RESULTS: In Study 1, higher levels of low sensory threshold (ß=0.210), traumatic experiences of physical threat (ß=0.141), neurotic defences (ß=0.124), and mental pain (ß=0.241) emerged as the strongest predictors of increased CS. In Study 2, the presented model demonstrated a satisfactory fit (chi2=27.200; df=10; p=0.002; GFI=0.984; NFI=0.949; CFI=0.967; RMSEA=0.061 [95% CI 0.034-0.090]) with large and medium effect sizes on physical (-0.576) and psychological (-0.190) QoL. CONCLUSIONS: The study underscores the pivotal role of psychological dimensions in influencing CS levels and their relationships with QoL in patients with FM.

Validation of Qualisex questionnaire to evaluate sexual dysfunction in women affected by fibromyalgia.

OBJECTIVES: Fibromyalgia (FM) may have consequences on sexual life. The objective was to validate the Qualisex questionnaire in the assessment of sexual dysfunction in women affected by FM. METHODS: We consecutively enrolled FM women (American College of Rheumatology-ACR 2016) referring to our Fibromyalgia Clinic, from 2020 to 2022. Demographic, clinical data and evaluation of FM symptoms severity (Revised Fibromyalgia Impact Questionnaire (R-FIQ), Symptoms Severity Scale-SSS, Widespread Pain Index-WPI) were assessed. Hospital Anxiety and Depression Scale (HADS) and Qualisex questionnaire were anonymously administered. Qualisex includes 10 questions on different items of sexual life with higher scores suggestive of greater negative impact of the disease on sexuality. RESULTS: The cohort was composed by 373 FM women. Cronbach's alpha test was used to validate Qualisex questionnaire (0.878). Moreover, we observed higher values of Qualisex in married women (p<0.001), in women with lower grade of education (p=0.002) and with lower sexual feeling with partner (p<0.001). Higher values of Qualisex Total score showed a positive correlation with HADS-A/D (p<0.001 r=0.312; p<0.001 r=0.542 respectively), VAS pain, VAS fatigue, VAS dryness (p<0.001 r=0,438; p<0.001 r=0.375; p<0.001 r=0.370 respectively) and relationship duration (p<0.001 r=0.202). Multivariate analysis revealed a significant influence of relationship duration, VAS pain, fatigue, dryness, HADS-A/D, R-FIQ and all Qualisex items, on Qualisex Total score corrected for patients' age (p<0.001). CONCLUSIONS: This study validated Qualisex questionnaire as a good test for the sexual disorders' evaluation in FM women. Its use allows the assessment of different factors associated with sexual dysfunction, showing an impact of FM on sexuality. Moreover, due to demotivation feelings, sexual dysfunction contributes to worsen patients' quality of life.

Unraveling the Complex Web of Fibromyalgia: A Narrative Review.

Fibromyalgia is a complex and often misunderstood chronic pain disorder. It is characterized by widespread musculoskeletal pain, fatigue, and heightened sensitivity, and has evolved in diagnostic criteria and understanding over the years. Initially met with skepticism, fibromyalgia is now recognized as a global health concern affecting millions of people, with a prevalence transcending demographic boundaries. The clinical features and diagnosis of fibromyalgia encompass a range of symptoms beyond pain, including sleep disturbances and cognitive difficulties. This study emphasizes the importance of a comprehensive evaluation for accurate diagnosis, considering the shift from tender point reliance to a more holistic approach. Etiology and pathophysiology involve genetic predisposition, neurotransmitter dysregulation, central sensitization, and immune system involvement. Risk factors such as gender, age, family history, and comorbid conditions contribute to susceptibility. The impact on quality of life is profound, affecting physical and social aspects, often accompanied by mood disorders. Management approaches include pharmacological interventions, non-pharmacological therapies, lifestyle modifications, and alternative treatments. This study also delves into emerging research, exploring advances in neurobiological understanding, brain imaging, genetic markers, glutamate modulation, cannabinoids, gut microbiome, and digital health tools for fibromyalgia management. Overall, this study provides a nuanced and up-to-date overview of the complexities surrounding fibromyalgia, aiming to enhance understanding and support for individuals grappling with this challenging condition.

Reprint of "Residual pain in rheumatoid arthritis: Is it a real problem?"

Pain is a significant issue in rheumatoid arthritis (RA) and can have a negative impact on patients' quality of life. Despite optimal control of inflammatory disease, residual chronic pain remains a major unmet medical need in RA. Pain in RA can be secondary to inflammation but can also generate neuroendocrine responses that initiate neurogenic inflammation and enhance cytokine release, leading to persistent hyperalgesia. In addition to well-known cytokines such as TNFα and IL-6, other cytokines and the JAK-STAT pathway play a role in pain modulation and inflammation. The development of chronic pain in RA involves processes beyond inflammation or structural damage. Residual pain is often observed in patients even after achieving remission or low disease activity, suggesting the involvement of non-inflammatory and central sensitization mechanisms. Moreover, fibromyalgia syndrome (FMS) is prevalent in RA patients and may contribute to persistent pain. Factors such as depression, sleep disturbance, and pro-inflammatory cytokines may contribute to the development of fibromyalgia in RA. It is essential to identify and diagnose concomitant FMS in RA patients to better manage their symptoms. Further research is needed to unravel the complexities of pain in RA. Finally, recent studies have shown that JAK inhibitors effectively reduce residual pain in RA patients, suggesting pain-reducing effects independent of their anti-inflammatory properties.

Is fibromyalgia an autoimmune disorder?

Fibromyalgia (FM) is a multifactorial syndrome which includes not only widespread pain and stiffness, now recognized as major symptoms, but also numerous other somatic, emotional, and neuropsychic manifestation. The lack of specific validated biological and instrumental biomarkers has made FM a condition of unexplained medical significance, and its pathophysiology remains controversial and subject to debate. The current hypothesis regarding the pathogenesis of FM proposes that its development is influenced by various mechanism, including genetic predisposition, stressful life events, inflammatory processes, and cognitive-emotional factors. However, despite the extensive research conducted to date, the available data do not provide a clear understanding of the pathogenesis of FM. In this article, we report the opposing viewpoints of two leading experts who debate the question of whether FM is an autoimmune disease, based on scientific data regarding this condition. Both perspectives are discussed and the latest evidence on the pathophysiology of FM is reported to provide a comprehensive understanding of this complex syndrome.

Comorbidities in the Spondyloarthritis GISEA Cohort: an average treatment effect analysis on patients treated with bDMARDs.

OBJECTIVES: We aimed to investigate the effectiveness of tumour necrosis factor inhibitors (TNFi), anti-interleukin-17 or interleukin-12/23 monoclonal antibodies (anti-IL) on comorbidities in a cohort of patients with spondyloarthritis (SpA), using an average treatment effect (ATE) analysis. METHODS: SpA patients from the multicentre Italian GISEA Registry were divided into groups according to pharmacological exposure: no treatment (G0), TNFi (G1) and non-responders to TNFi switched to anti-IL (G2). In each group, we recorded the prevalence and incidence of infectious, cardiopulmonary, endocrinological, gastrointestinal, oncologic, renal and neurologic comorbidities. Each comorbidity was then fitted for ATE and baseline features were evaluated for importance. RESULTS: The main findings of this study comprising 4458 SpA patients relate to cancer, other gastrointestinal diseases (OGID) and fibromyalgia. ATE showed no increased risk of solid cancer in G1 (0.42 95% CI 0.20-0.85) and G2 (0.26 95% CI 0.08-0.71) vs. G0, with significantly higher incidence in G0 (14.07/1000 patient-years, p=0.0001). Conversely, a significantly higher risk of OGID and fibromyalgia was found in G1 (1.56 95% CI 1.06-2.33; 1.69 95% CI 1.05-2.68, respectively) and G2 (1.91 95% CI 1.05-3.24; 2.13 95% CI 1.14-3.41, respectively) vs. G0. No treatment risk reduction was observed in haematological malignancies, cardiovascular events and endocrinological comorbidities. CONCLUSIONS: Overall, our study confirms the safety of TNFi and anti-IL in SpA patients, albeit with some caveats pertaining to solid cancers, OGID and fibromyalgia. Furthermore, taking into consideration causality with observational data may yield more reliable and relevant clinical information.

Feldenkrais awareness though movement intervention for fibromyalgia syndrome: A proof-of-concept study.

INTRODUCTION: The Feldenkrais Method® is a form of awareness through movement (ATM) aimed at improving spatial and kinesthetic awareness through verbally guided movements, in order to learn more effective actions. METHOD: The present study, a proof-of-concept, observational, non-controlled prospective study, aims at exploring the effectiveness of ATM for fibromyalgia syndrome (FM), measuring the effect by means of multi-dimensional questionnaires, administered at baseline and after 4 months of ATM activity. RESULTS: One hundred twenty-eight FM patients (mean age 54 years old, 2% males) participated in the study. A statistically significant improvement was found in FM-specific measures (Polysymptomatic Distress Scale, PDS) (p = 0.003) and the Pain Catastrophization Scale (PCS) (p = 0.020); coherently, the Revised Fibromyalgia Impact Questionnaire (FIQR) showed a trend in improvement after the intervention, although this improvement was not statistically significant. The logistic regression analysis found a correlation between PDS, fatigue and anxiety measures; PCS, years from diagnosis and anxiety. CONCLUSION: ATM could improve FM-specific measures and pain-related catastrophizing. Further studies are needed to identify FM subgroups in order to find personalized targets that can be used to guide treatments.

Is Fibromyalgia a Fashionable Diagnosis or a Medical Mystery?

Despite its prevalence, there is no clear-cut diagnostic path or treatment paradigm for fibromyalgia; this can lead to a multiplicity of symptoms and comorbid conditions that complicate care. "Overlapping symptoms" describe conditions that can occur concomitantly with fibromyalgia and include migraine, irritable bowel syndrome, obesity, and pelvic pain syndromes. A variety of pharmacologic and nonpharmacologic treatments are available for fibromyalgia, but treatment is best personalized for an individual and recognizes potential comorbidities. Opioids are not the recommended front-line treatment, cannabinoids hold promise but with limitations and nonpharmacologic options, such as aerobic or resistance exercise and cognitive behavior therapy, can play a very important but often underestimated role. Amitriptyline appears to be safe and effective in treating six of the main fibromyalgia domains: pain, disturbed sleep, fatigue, affective symptoms, functional limitations, and impaired cognition ("fibro fog"). Very low-dose naltrexone (2.5-4.5 mg) may offer analgesic and anti-inflammatory benefits to fibromyalgia patients, but further studies are needed. Fibromyalgia can be a devastating and debilitating condition for patients, and clinicians are challenged with its diagnosis and treatment as well. Further research as well as compassionate approaches to offering personalized care to those with fibromyalgia are required.

Residual pain in rheumatoid arthritis: Is it a real problem?

Pain is a significant issue in rheumatoid arthritis (RA) and can have a negative impact on patients' quality of life. Despite optimal control of inflammatory disease, residual chronic pain remains a major unmet medical need in RA. Pain in RA can be secondary to inflammation but can also generate neuroendocrine responses that initiate neurogenic inflammation and enhance cytokine release, leading to persistent hyperalgesia. In addition to well-known cytokines such as TNFα and IL-6, other cytokines and the JAK-STAT pathway play a role in pain modulation and inflammation. The development of chronic pain in RA involves processes beyond inflammation or structural damage. Residual pain is often observed in patients even after achieving remission or low disease activity, suggesting the involvement of non-inflammatory and central sensitization mechanisms. Moreover, fibromyalgia syndrome (FMS) is prevalent in RA patients and may contribute to persistent pain. Factors such as depression, sleep disturbance, and pro-inflammatory cytokines may contribute to the development of fibromyalgia in RA. It is essential to identify and diagnose concomitant FMS in RA patients to better manage their symptoms. Further research is needed to unravel the complexities of pain in RA. Finally, recent studies have shown that JAK inhibitors effectively reduce residual pain in RA patients, suggesting pain-reducing effects independent of their anti-inflammatory properties.

The 2023 ACR/EULAR Classification Criteria for Calcium Pyrophosphate Deposition Disease.

OBJECTIVE: Calcium pyrophosphate deposition (CPPD) disease is prevalent and has diverse presentations, but there are no validated classification criteria for this symptomatic arthritis. The American College of Rheumatology (ACR) and EULAR have developed the first-ever validated classification criteria for symptomatic CPPD disease. METHODS: Supported by the ACR and EULAR, a multinational group of investigators followed established methodology to develop these disease classification criteria. The group generated lists of candidate items and refined their definitions, collected de-identified patient profiles, evaluated strengths of associations between candidate items and CPPD disease, developed a classification criteria framework, and used multi-criterion decision analysis to define criteria weights and a classification threshold score. The criteria were validated in an independent cohort. RESULTS: Among patients with joint pain, swelling, or tenderness (entry criterion) whose symptoms are not fully explained by an alternative disease (exclusion criterion), the presence of crowned dens syndrome or calcium pyrophosphate crystals in synovial fluid are sufficient to classify a patient as having CPPD disease. In the absence of these findings, a score >56 points using weighted criteria, comprising clinical features, associated metabolic disorders, and results of laboratory and imaging investigations, can be used to classify as CPPD disease. These criteria had a sensitivity of 92.2% and specificity of 87.9% in the derivation cohort (190 CPPD cases, 148 mimickers), whereas sensitivity was 99.2% and specificity was 92.5% in the validation cohort (251 CPPD cases, 162 mimickers). CONCLUSION: The 2023 ACR/EULAR CPPD disease classification criteria have excellent performance characteristics and will facilitate research in this field.

The 2023 ACR/EULAR classification criteria for calcium pyrophosphate deposition disease.

OBJECTIVE: Calcium pyrophosphate deposition (CPPD) disease is prevalent and has diverse presentations, but there are no validated classification criteria for this symptomatic arthritis. The American College of Rheumatology (ACR) and EULAR have developed the first-ever validated classification criteria for symptomatic CPPD disease. METHODS: Supported by the ACR and EULAR, a multinational group of investigators followed established methodology to develop these disease classification criteria. The group generated lists of candidate items and refined their definitions, collected de-identified patient profiles, evaluated strengths of associations between candidate items and CPPD disease, developed a classification criteria framework, and used multi-criterion decision analysis to define criteria weights and a classification threshold score. The criteria were validated in an independent cohort. RESULTS: Among patients with joint pain, swelling, or tenderness (entry criterion) whose symptoms are not fully explained by an alternative disease (exclusion criterion), the presence of crowned dens syndrome or calcium pyrophosphate crystals in synovial fluid are sufficient to classify a patient as having CPPD disease. In the absence of these findings, a score>56 points using weighted criteria, comprising clinical features, associated metabolic disorders, and results of laboratory and imaging investigations, can be used to classify as CPPD disease. These criteria had a sensitivity of 92.2% and specificity of 87.9% in the derivation cohort (190 CPPD cases, 148 mimickers), whereas sensitivity was 99.2% and specificity was 92.5% in the validation cohort (251 CPPD cases, 162 mimickers). CONCLUSION: The 2023 ACR/EULAR CPPD disease classification criteria have excellent performance characteristics and will facilitate research in this field.

Palmitoylethanolamide and acetyl-L-carnitine act synergistically with duloxetine and pregabalin in fibromyalgia: results of a randomised controlled study.

OBJECTIVES: Fibromyalgia (FM) is characterised by a form of debilitating pain that is unresponsive to standard analgesics. The aim of this study was to evaluate the efficacy of supplementing ongoing pregabalin (PGB) and duloxetine (DLX) treatment with palmitoylethanolamide (PEA) and acetyl-L-carnitine (ALC) for 24 weeks in FM patients. METHODS: After undergoing three months of stable treatment with DLX+PGB, FM patients were randomised to continue the same treatment (Group 1) or to add PEA 600 mg b.i.d + ALC 500 mg b.i.d. (Group 2) for a further 12 weeks. Every two weeks throughout the study, cumulative disease severity was estimated using the Widespread Pain Index (WPI) as the primary outcome measure; the secondary outcomes were the fortnightly scores of the patient-completed revised Fibromyalgia Impact Questionnaire (FIQR) and the modified Fibromyalgia Assessment Status (FASmod) questionnaire. All three measures were expressed as time-integrated area under the curve (AUC) values. RESULTS: One hundred and thirty (91.5%) of the initial 142 FM patients completed the study: 68 patients in Group 1 and 62 in Group 2. Twenty-four weeks after randomisation, the Group 2 patients showed additional significant improvements in all three outcome measures. Although there was some fluctuation in both groups during the study period, the AUC values of the WPI scores steadily decreased in Group 2 (p=0.048), which also showed better outcomes in terms of the AUC values of the FIQR (p=0.033) and FASmod scores (p=0.017). CONCLUSIONS: This is the first randomised controlled study demonstrating the effectiveness of the adding on therapy of PEA+ALC to DLX+PGB in FM patients.

Consistency between the 2016 ACR criteria and a previous diagnosis or hypothesis of fibromyalgia in a specialised referral clinic.

OBJECTIVES: Fibromyalgia (FM) is a complex syndrome whose hallmark features are chronic widespread pain, sleep disturbances, fatigue and cognitive dysfunctions. However, it is still difficult to apply validated diagnostic criteria. The aim of this study is to examine the accuracy of a previous diagnosis/diagnostic hypothesis of FM according to the 2016 ACR diagnostic criteria. METHODS: All of the patients newly referred to a private rheumatological clinic with the specific request for a consultation because if FM over an 18-month period were evaluated by means of a standardised protocol in order to determine whether they fulfilled the 2016 ACR diagnostic criteria for FM. They were initially divided into three groups: those with a previous diagnosis of FM (group 1), those with a physician's diagnostic hypothesis of FM (group 2) and those who personally hypothesised FM (group 3). They were subsequently classified as having FM, IFM (borderline scores) or not having FM (non-FM) on the basis of the 2016 ACR diagnostic criteria. RESULTS: The study involved 216 patients (25 males and 191 females): 112 in group 1, 49 in group 2, and 55 in group 3. Only 89 patients (41.2%) fulfilled the ACR criteria; 42 (19.44%) met the study protocol-defined scores for IFM; and 85 (39.35%) were diagnosed as not having FM. Only 50% of the patients with a previous diagnosis of FM fulfilled the ACR criteria, and just under 25% did not have FM. Almost 50% of the patients with a physician's diagnostic hypotheses of FM did not have FM, whereas 20% of the patients who personally hypothesised FM fulfilled the ACR criteria. GP scores and TPCs were significantly different (FM > IFM, FM > non-FM, and IFM > non-FM) as were WPI, SSS and PSD scores for FM > IFM group. Rheumatologists made the previous diagnosis in 92.85% of patients, 53.84% of whom met the ACR criteria and about 20% did not have FM; and as many as 37.5% of the patients with a previous diagnosis made by a non-rheumatologist did not have FM. The non-FM patients were given 84 alternative diagnoses, 78.5% of which referred to rheumatic diseases. One hundred and thirty-one patients had 86 closely pain-related co-morbidities, 94.1% of which were rheumatic diseases. CONCLUSIONS: Our findings confirm the inaccuracy of FM diagnoses and highlights the possibility that in everyday clinical practice, they are not always made with reference to very specific criteria and that there is a high risk of classifying non-FM patients as having FM. They also underline the importance of an accurate differential diagnosis. Separately classifying as IFM those patients who do not meet the ACR criteria, but have clinical findings indicating FM, may help to prevent their exclusion from specific treatment(s).

Is psyche-soma dichotomy still clinically appropriate?

This article proposes a historical recontextualisation of the mind-body relationship and offers some evidence-based reflections on the current clinical appropriateness of psyche-soma dichotomy and psychosomatics. The debate concerning the mind-body relationship has a long medical, philosophical, and religious history, with psyche-soma dichotomy and psychosomatics alternating as the dominant clinical approach, depending on the prevalence of cultural orientations at different times. However, both models simultaneously benefit and limit the clinical practice.The neurosciences have reduced the gap between psyche and soma diseases, which can now be seen as overlapping and sharing a common pathogenesis. Diseases should also be considered as illnesses by considering all of their biopsychosocial aspects to avoid therapeutic failures due to only partially effective or ineffective interventions. Patient-centred care integrated with guideline recommendations may be the best means of uniting the psyche and the soma.

Gender differences in the revised Fibromyalgia Impact Questionnaire: a pilot study.

OBJECTIVES: Fibromyalgia (FM) is a chronic syndrome characterised by widespread musculoskeletal pain associated with symptoms such as fatigue, sleep disturbances and cognitive impairment. Prevalence is higher in females but the application of the 2010/2011 and 2016 revision of the American College of Rheumatology (ACR) criteria reduced prevalence differences and the actual female:male ratio is approximately 3:1. Even if lately some studies have been conducted regarding FM gender differences, disease severity is still assessed using questionnaires, such as the Revised Fibromyalgia Impact Questionnaire (FIQR), designed and validated through a predominantly female sample. The aim of this pilot study was to compare the 21 items of the FIQR among male and female patients in order to evaluate the possible existence of a gender bias. METHODS: In this case-control study, consecutive patients with a diagnosis of FM (2016 ACR criteria) were asked to answer an online survey, including demographic characteristics, disease variables and the Italian version of the FIQR. Among the 544 patients that compiled the questionnaire, 78 patients, 39 males and 39 females, matched for age and disease duration, were consecutively enrolled in order to compare their FIQR scores. RESULTS: The univariate analysis showed that total FIQR scores and physical function domain scores were significantly higher in females and, among the 21 items of the FIQR, the female group obtained significantly higher scores in 6 of them. Our results showed that female patients obtain significantly higher scores in the FIQR total score and physical function domain score, in particular in 5 out of the 9 sub-items of the FIQR physical function domain. CONCLUSIONS: These preliminary results indicate that the use of the FIQR as a severity index in male patients probably underestimates the disease impact in this group.