Exploring fibromyalgia patients by gender using routinely collected primary-care data from wales, uk: a descriptive epidemiological study

Abstract Background/Aims Fibromyalgia predominantly affects women (80-90%), however contradictory findings show lower estimates (59%). The psychosocial impacts are similar in men and women but men delay seeking treatment and medical advice. Revisions of the 1990 American College of Rheumatology fibromyalgia classification criteria removed the requirement for at least 11 of 18 tender-point sites, which led to various prevalence rates and female-to-male ratios. This study aimed to measure new cases of fibromyalgia, determine the sex ratio following criteria revisions and explore treatments and symptoms by gender. Methods A retrospective population-based cohort study using primary-care electronic health-data from the Secured Anonymised Information Linkage Databank in Wales. Individuals aged 18 years and over with fibromyalgia READ Codes (N239’. and ‘N248.’) between 2004 and 2018 were included in the study. New cases were defined at first appearance of fibromyalgia READ codes. New cases of fibromyalgia were calculated at three 5-year periods; period 1 (2004-2008), 2 (2009-2013) and 3 (2014-2018). Descriptive analysis performed on variables for individuals by gender. Results Data on 22,568 individuals with fibromyalgia were extracted. The mean age of individuals was 48 years (SD: 13) and 20,040 (88.8%) were female. In period 1, among 5,296 new cases of fibromyalgia, 784 (14.8%) were male and 4,512 (85.2%) were female. In period 2, 642 (10.8%) of 5,958 new cases were male and 5,316 (89.2%) female, while in period 3, 1,102 (9.7%) of 11,314 new cases were male and 10,212 (90.3%) female. Women had a significantly higher BMI compared to men (difference: 1.6%, 95% CI: 1.5 - 1.7) and experienced more widespread pain (difference: 3.9%, 95% CI: 2.4 - 5.6). Women also experienced more stress and bereavement (difference: 12.1%, 95% CI: 10.3 - 13.8) and adverse life events (difference 10.4%, 95% CI: 9.1 - 11.6) compared to men. Men had significantly more comorbidities however women had more gastrointestinal disorders (difference 10%, 95% CI: 8.4-11.4) and abnormal thyroid function (difference 3.3%, 95% CI: 2.7-3.8). Significantly more women received steroid treatment (difference: 8.3%, 95% CI: 6.3-10.3), antidepressants (difference: 5.4%, 95% CI: 4.2-6.6), anxiolytics and barbiturates (difference: 7.2%, 95% CI: 5.2-9.2) and vitamin D (difference: 1.8%, 95% CI: 1.0-2.5), while significantly more men were treated with gabapentin (difference: 9%, 95% CI: 7.0-11). Conclusion Routinely collected health-data does not demonstrate an increase in fibromyalgia in men despite changes in classification criteria. Fibromyalgia may be underdiagnosed in men. However, significant gender differences in men and women living with fibromyalgia were observed. Different medications used may represent clinician or patient choice and is worthy of future study. Disclosure R. Cooksey: Grants/research support; Pfizer. E. Choy: Grants/research support; Abbvie, Amgen, AstraZeneca, Biogen, Bio-Cancer, Biocon, BMS, Boehringer Ingelheim, Celgene, Chugai Pharma, Eli Lilly, Galapagos Gilead, Janssen, Novimmune, Novartis, ObsEva, Pfizer, Regneron, Roche, R-Pharm, Sanofi, SynAct Pharma, UCB.