Evidence for an association between endometriosis, fibromyalgia, and autoimmune diseases

The aim of this study was to investigate the prevalence of and the association between endometriosis, fibromyalgia, and autoimmune disease (AID) in a large population database and to describe healthcare resource utilization (HCRU) in affected women.

A retrospective cross-sectional study was performed using the computerized databases of Maccabi Healthcare Services (MHS), a 2.1-million-member healthcare plan in Israel. Age-sex-specific point prevalence rates of endometriosis and fibromyalgia were calculated for end of 2015. Socio-demographic characteristics, HCRU, co-morbidities, including AID and depression or anxiety were described according to endometriosis/fibromyalgia status and analyzed using ordinary logistic regression models.

Among a total population of 781 571 adult women, 6647 were diagnosed with endometriosis (8.5 per 1000) and 25 425 with fibromyalgia (32 per 1000). A total of 401 women (0.5 per 1000) were diagnosed with both conditions. In 2015, the mean age of the women diagnosed with endometriosis and fibromyalgia was 42 and 55 years, respectively. Women with co-occurrence were characterized by increased HCRU and a high prevalence rate of AID compared to women with no diagnosis of endometriosis/fibromyalgia, with 6.2% diagnosed with inflammatory bowel disease (IBD) vs 1% in the comparison group. The prevalence of fibromyalgia in women with endometriosis was 6%. Adjusted ORs (95% CI) for fibromyalgia among endometriosis patients were 4.1 (2.02-8.36) for systemic lupus erythematosus (SLE), 3.1 (1.5-6.2) for Sjögren syndrome, 2.9 (1.87-4.7) for IBD, 2.1 (1.6-2.7) for dispensed antidepressants, and 1.7 (1.37-2.2) for diagnosed anxiety/depression.

Co-occurrence of endometriosis and fibromyalgia is associated with a high burden of AID, anxiety/depression, and HCRU.