Prevalence and Clinical Correlates of Endometriosis in Patients With IC/BPS.

Importance: Interstitial cystitis/bladder pain syndrome (IC/BPS) presents as a complex heterogeneous disorder that poses a significant clinical challenge both for diagnosis and treatment. The identification of patient subgroups with significant overlap in their nonurological associated symptoms, including endometriosis, may enable a more targeted therapeutic approach.

Objective: This study investigated the prevalence, clinical correlates, and clinical sequelae associated with concurrent endometriosis in patients with IC/BPS.

Study design: Demographic, clinical, surgical, and questionnaire data from female patients (n = 533) with a diagnosis of IC/BPS were evaluated in this retrospective cohort study. Surgical history was obtained from patient electronic medical records, using Current Procedural Terminology (CPT) and International Classification of Diseases (ICD) codes. Data from participants with and without concurrent endometriosis were compared using univariate analysis, followed by binary logistic regression to identify associated variables.

Results: Of 533 participants, 108 (20.3%) reported a history of endometriosis. Those with concurrent endometriosis were younger, had a larger bladder capacity, and had a higher number of nonurological associated symptoms. Patients with concurrent endometriosis were less likely to have a history of cystectomy (the surgical removal of the bladder) and report allergies but more prone to report comorbidities such as chronic pelvic pain, chronic fatigue, fibromyalgia, migraines, and pelvic floor dysfunction. Binary logistic regression identified a positive association between endometriosis and chronic pelvic pain, and a negative association between allergies and low bladder capacity for those with concurrent endometriosis.

Conclusions: Endometriosis is common in younger female patients with IC/BPS and is associated with a non-bladder-centric (ie, systemic pain disorder) phenotype.