Background:Fibromyalgia (FM) is a common rheumatic disease characterized by chronic widespread pain, sleep and mood disorders. A higher prevalence of FM in women compared with men is well known, although the specific differences in clinical manifestations related to gender are still poorly defined. Brain-Derived Neurotrophic Factor (BDNF) is an endogenous growth factor that gained attention for its potential as biomarker of several diseases, including FM and depression.Objectives:The aims of this study were to investigate gender-related difference among males and females affected by FM in clinical manifestations, depressive features and BDNF serum level, evaluating also the diagnostic potential of the latter.Methods:We consecutively enrolled adult patients affected by FM (ACR 2016) referring to our out-patient clinic. Each subject underwent clinical and answered to questionnaires for the severity of FM symptoms (Revised Fibromyalgia Impact Questionnaire, R-FIQ) and depressive symptoms (Beck Depression Inventory-II, BDI-II). We collected blood samples from a subgroup of patients of both sexes, matched for age, for BDNF serum level dosage through ELISA. BDNF levels were assessed also in a control group, matched for sex and age.Results:The cohort was composed by 201 FM patients (172 F, 29 M), mean age 49.13. Females showed higher values of R-FIQ total score (p=0,0005) as well the specific items of the R-FIQ for pain (p=0,013), fatigue (p=0,014), memory problems (p=0,007), tenderness to touch (p<0,0001), balance problems (p<0,0001) and sensitivity to environmental stimuli (p=0,012) when compared with males (fig. 1). There was no difference in BDI-II between males and females, but notably male patients reported a significantly higher frequency of coexisting depressive disorder (p=0,038) (fig. 2). Serum BDNF levels were evaluated in 40 FM patients and 40 healthy controls (HC) (F:M 1:1). BDNF levels were significantly lower in FM patients compared with HC (p<0,0001). Among FM patients, BDNF levels were lower in males compared with females (p<0,0001) (fig.3). BDNF did not correlate with any clinical and clinimetric parameter. BDNF showed a good diagnostic performance (AUC=0,89, CI95%=0,82-0,9630, p<0,0001) (fig. 4). At a cut-off value <6,47 ng/dl, BDNF showed a specificity of 75% and a sensibility of 92,31%,(CI 95%=79,68-97.35) for FM identification (LR=3,692).Conclusion:FM clinical manifestations are strongly dependant from gender. While females present a more severe disease and a higher burden of symptoms, mood disorders tend to be a major characteristic of males with FM. Reduced BDNF serum levels have been reported as typical of depressive disorders. Our findings of lower BDNF levels in male FM patients compared to females support this hypothesis. BDNF have potential as biomarker of the disease and should be validated in larger cohorts.References:[1]Sarzi-Puttini et al. Nature Reviews 2020[2]Colucci-D’Amato et al. Int J Molecular Sciences 2020[3]Nugraha et al. Rheumatol Int 2012[4]Schmitt et al. Ann Med 2016[5]Melchior et al. Neuroscience 2016[6]Stefani et al. Neuroscience Letters 2012Disclosure of Interests:None declared
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