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.