Non-bladder centric interstitial cystitis/bladder pain syndrome phenotype is significantly associated with co-occurring endometriosis.

INTRODUCTION: Interstitial cystitis/bladder pain syndrome (IC/BPS) and endometriosis are coexistent diagnoses in 48%-65% of women with chronic pelvic pain (CPP), suggesting that dual screening may be warranted. To further investigate the clinical relationship and risk factors between these two conditions, we performed a retrospective review of our large IC/BPS patient data registry. MATERIALS AND METHODS: We evaluated IC/BPS patients who were prospectively enrolled into our registry who completed validated questionnaires and underwent therapeutic hydrodistension, during which anesthetic bladder capacity (BC) and Hunner's lesion (HL) status were recorded. Demographic/medical history were reviewed. IC/BPS patients with co-occurring endometriosis diagnosis versus those without were compared using descriptive statistics as well as multivariate regression analyses to determine predictors of co-occurring disease. RESULTS: Of 431 IC/BPS participants, 82 (19%) were also diagnosed with endometriosis. These women were significantly younger, had increased prevalence of non-low BC (> 400 cc), and decreased prevalence of HL (p < 0.05). Patients with co-occurring endometriosis also had increased prevalence of irritable bowel syndrome (IBS), CPP, fibromyalgia, and vulvodynia (p < 0.05). On multivariate analysis, non-low BC (OR 4.53, CI 1.004-20.42, p = 0.049), CPP (OR 1.84, CI 1.04-3.24, p = 0.04), and fibromyalgia (OR 1.80, CI 1.03-3.14, p < 0.04) were significantly associated with a diagnosis of endometriosis. CONCLUSIONS: Patients with IC/BPS and co-occurring endometriosis were significantly more likely to carry a non-bladder centric IC/BPS phenotype as well as several comorbid, systemic pain diagnoses. This study characterizes features of a target IC/BPS phenotype that could potentially benefit from endometriosis and systemic pain syndrome screening.