UBC Faculty Research and Publications

Pelvic Pain Comorbidities Associated with Quality-of-life after Endometriosis Surgery Tucker, Dwayne; Noga, Heather; Lee, Caroline E.; Chiu, Derek; Bedaiwy, Mohamed Ali; Williams, Christina; Allaire, Catherine; Talhouk, Aline; Yong, Paul J.

Abstract

Background: After endometriosis surgery, pain can persist or recur in a subset of patients. A possible reason for persistent pain post-surgery is central nervous system sensitization and associated pelvic pain comorbidities. Surgery addresses the peripheral component of endometriosis pain pathophysiology (by lesion removal) but may not treat this centralized pain. Therefore endometriosis patients with pelvic pain comorbidities related to central sensitization may experience worse pain-related outcomes after surgery, such as lower pain-related quality-of-life. Objective: To determine whether baseline (preoperative) pelvic pain comorbidities are associated with pain-related quality-of-life at follow-up after endometriosis surgery. Study Design: This study utilized longitudinal prospective registry data from the Endometriosis and Pelvic Pain Interdisciplinary Cohort at the BC Women’s Center for Pelvic Pain and Endometriosis. Subjects were ≤ 50 years old with confirmed or clinically suspected endometriosis, who underwent surgery (fertility-sparing or hysterectomy) for endometriosis pain. Subjects completed the pain subscale of the Endometriosis Health Profile (EHP-30) quality-of-life questionnaire preoperatively and at follow-up (1-2 years). Linear regression was performed to measure the individual relationships between seven pelvic pain comorbidities at baseline and follow-up EHP- 30 score, controlling for baseline EHP-30 and type of surgery received. These baseline (preoperative) pelvic pain comorbidities included abdominal wall pain, pelvic floor myalgia, painful bladder syndrome, irritable bowel syndrome, Patient Health Questionnaire (PHQ-9) depression score, General Anxiety Disorder (GAD-7) score, and Pain Catastrophizing Scale (PCS) score. LASSO regression was then performed to select the most important variables associated with follow-up EHP-30 from among seventeen covariates (including the seven pelvic pain comorbidities, baseline EHP-30 score, type of surgery, and other endometriosis-related factors such as stage and histologic confirmation of endometriosis). Using 1000 bootstrap samples, we estimated the coefficients and confidence intervals of the selected variables and generated a covariate importance rank. Results: The study included 444 subjects. The median follow-up time was 18 months. Pain-related quality-of-life (EHP-30) of the study population significantly improved at follow-up after surgery (p<0.001). The following pelvic pain comorbidities were associated with lower quality-of-life (higher EHP-30 score) after surgery controlling for baseline EHP-30 score and type of surgery (fertility-sparing vs. hysterectomy): abdominal wall pain (p=0.013), pelvic floor myalgia (p=0.036), painful bladder syndrome (p=0.022), PHQ-9 score (p<0.001), GAD-7 score (p<0.001), and PCS score (p=0.007). Irritable bowel syndrome was not significant (p=0.70). Of the seventeen covariates included for LASSO regression, six remained in the final model (lambda = 3.136). These included three pelvic pain comorbidities that were associated with higher follow-up EHP-30 scores or worse quality-of-life: abdominal wall pain (β = 3.19), pelvic floor myalgia (β = 2.44), and PHQ-9 depression score (β = 0.49). The other three variables in the final model were baseline EHP-30 score, type of surgery, and histologic confirmation of endometriosis. Conclusion: Pelvic pain comorbidities present at baseline before surgery, which may reflect underlying central nervous system sensitization, are associated with lower pain related quality-of-life after endometriosis surgery. Particularly important were depression and musculoskeletal/myofascial pain (abdominal wall pain and pelvic floor myalgia). Therefore, these pelvic pain comorbidities should be candidates for a formal prediction model of pain outcomes after endometriosis surgery.

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