Prevalence and incidence of diagnosed endometriosis and risk of endometriosis in patients with endometriosis-related symptoms: findings from a statutory health insurance-based cohort in Germany

Abstract

Objective The objectives were: (a) to determine the administrative prevalence and incidence of endometriosis and (b) to assess the risk of endometriosis associated with endometriosis-related symptoms. Study design The study is based on inpatient and outpatient data from a statutory health insurance fund in Germany. For prevalence and incidence definition 62,323 women aged 15–54 continuously insured in 2007 were identified. The prevalence and incidence of endometriosis in 2007 were calculated standardized to the age distribution in Germany. In a further prospective cohort study based within the health insurance sample 2095 patients with endometriosis-related symptoms and 8380 age-matched asymptomatic controls were identified. Endometriosis follow-up was from 2004 to 2008. Cox proportional hazard regression was used to examine the risk of endometriosis associated with endometriosis-related symptoms, such as pelvic pain, dysmenorrhoea, dyspareunia, menorrhagia, post-coital bleeding, inter-menstrual pain and ovarian cysts. Relative risks (RR) and 95% confidence intervals (CI) were calculated. Results Standardized prevalence and incidence rates were 8.1 and 3.5 per 1000 women, respectively. The highest prevalence was observed in women aged 35–44 with 12.8 per 1000 women. Median follow-up was 4.5 years. Risk of endometriosis associated with endometriosis-related symptomatology was RR (95% CI) = 4.95 (3.67–6.68); 4.5% of all symptomatic women were diagnosed with endometriosis in a median follow-up of 4.5 years. The highest risk was observed in women aged 35–44 [RR (95% CI) = 6.29 (4.00–9.90)] with 7.6% of all symptomatic women receiving a diagnosis of endometriosis during the follow-up. Conclusion Prevalence estimates based on population-based administrative data were lower than described in the literature. Risk of endometriosis was increased in women with endometriosis-related symptoms. However, those symptoms were of limited predictive value for endometriosis as only a small proportion of symptomatic patients were diagnosed with endometriosis in the follow-up.