P-359 The prevalence of benign coexisting gynaecological conditions with endometriosis: a systematic review and meta-analysis
Authors: Sri Ranjan Y , Ziauddeen N , Alwan N A , Cheong Y 
Published: June 2023

Abstract

Study question
What is the prevalence of other benign gynaecological conditions in women with endometriosis. Are women with endometriosis at a higher risk of these conditions?

Summary answer
Women with endometriosis are at a higher risk of coexisting adenomyosis and endometrial polyps.

What is known already
Endometriosis is a chronic and debilitating condition with a prevalence of ∼10% in women of reproductive age. Over recent years, associations between endometriosis and other gynaecological and non-gynaecological conditions have been speculated but data on the prevalence of benign gynaecological conditions coexisting with endometriosis is limited. Furthermore, whether women with endometriosis are at an increased risk of other gynaecological conditions is unclear, particularly, when some of those conditions share a hormonally driven pathway to endometriosis. Understanding the risk of coexistence with endometriosis is crucial in establishing an association, providing insights into disease pathophysiology, informing clinical surveillance, and improving patient care.

Study design, size, duration
The review was prospectively registered in PROSPERO (id: CRD42022307527). MEDLINE and Embase was searched from inception to June 2022 with no restrictions. Experimental and population-based observational studies were included. Grading of Recommendations, Assessment, Development and Evaluation (GRADE) criteria was used to rate the quality of evidence with the risk of bias in non-randomized studies of interventions (ROBINS-I) tool incorporated. A random effects model was used to pool the odds ratio (OR) data.

Participants/materials, setting, methods
Coexisting gynaecological conditions included were adenomyosis, fibroids, endometrial polyps (EP), polycystic ovarian syndrome (PCOS), benign ovarian cysts (BOC) or pelvic inflammatory disease (PID). All conditions were diagnosed by surgery, imaging or ICD coded medical records. Comparison groups were women with and without endometriosis. Outcome was prevalence expressed as a fraction. All prevalence estimates were either drawn from original papers or calculated. Meta-analysis was carried out if at least two studies were available.

Main results and the role of chance
7137 studies were screened, and fifty-five studies reported on the prevalence of a coexisting gynaecological condition with endometriosis. Of these, 21 studies compared the prevalence in women without endometriosis and was included in the meta-analysis. The prevalence of coexisting adenomyosis (n = 34 studies; 11.0-91.9%.), fibroids (n = 16; 1.9-67.3%), EP (n = 14;1.6-68.4%.), PCOS (n = 3; 4.35-73.6%), BOC (n = 2;10.9-15.1%) and PID (n = 3;1.29-4.42) showed considerable variation between studies. Compared to women without endometriosis, women with endometriosis had a significantly higher prevalence of adenomyosis (OR 3.65, 95% CI 1.94-6.88, P &lt; 0.001) and EPs (OR 4.04, 95% CI 2.85-5.74, P &lt; 0.001) but not fibroids (OR 1.16, 95% CI 0.76-1.78, P = 0.5). There was insufficient comparative data for PCOS, BOC and PID. Overall, the quality of evidence for the prevalence estimate rated as low or very low on the GRADE criterion scale. The major factors associated with downgrading an outcome for quality was limitations in the study design and execution (risk of bias) and imprecision. The factors associated with increasing the quality of evidence was large effect sizes or sample sizes.

Limitations, reasons for caution
The wide variance in prevalences may be due to the differences in study design, study population, mode of diagnosis and criteria used to define the coexisting condition. The quality of evidence for prevalence effect estimates were low to very low quality, due to inherent biases associated with observational studies.

Wider implications of the findings
The wide variation in the prevalence of benign gynaecological conditions suggests over or under diagnosis. In our review endometriosis is associated with a significantly higher risk of adenomyosis and endometrial polyps. Clinicians may need to be mindful of this coexistence, but future high-quality studies are required to make robust conclusions.

Trial registration number
not applicable