Gender Differences in the Prevalence of Fibromyalgia and in Concomitant Medical and Psychiatric Disorders: A National Veterans Health Administration Study

Background: Fibromyalgia is a poorly understood, chronically disabling pain syndrome. While research has focused on its clinical presentation and treatment, less is known about fibromyalgia's clinical epidemiology in real-world healthcare systems. Gender differences have been difficult to study because relatively few males are diagnosed with fibromyalgia. Methods: Veterans Health Administration (VHA) patients diagnosed with fibromyalgia nationwide in FY 2012 were compared to Veterans with other pain diagnoses on sociodemographic characteristics, medical and psychiatric diagnoses, health service use, and opioid and psychotropic prescription fills. Additional analyses compared characteristics of men and women diagnosed with fibromyalgia. Risk ratios and Cohen's d were used for bivariate comparisons, followed by logistic regression analyses to identify independent factors associated with a diagnosis of fibromyalgia in the VHA. Results: Altogether, 77,087 of 2,216,621 Veterans with pain diagnoses (3.48%) were diagnosed with fibromyalgia. They were more likely to be female, younger than patients with other pain conditions, more likely to have multiple psychiatric comorbidities and other types of pain, and used more medical outpatient services. Women diagnosed with fibromyalgia were younger and more likely to have headaches, connective tissue diseases (CTD), and psychiatric comorbidities, while men had more comorbid medical conditions. Conclusions: In this large, predominantly older male sample of Veterans with pain diagnoses, those with fibromyalgia were far more likely to be women. Gender comparisons showed women with fibromyalgia were more likely to be diagnosed with psychiatric disorders and CTD, while males were more likely to be diagnosed with medical conditions. Fibromyalgia shows a striking, gender-dependent picture of multimorbidity, which should be considered in treatment.