(98) Patient characteristics associated with pain remediation one year after endometriosis-related surgery: EndoQUEST

Background: Not all patients with endometriosis will experience pain remediation after surgical treatment, but few predictors of treatment refractory chronic pain are known – especially among adolescents. We therefore assessed behavioral and symptom characteristics prior to surgery as predictors of pain symptoms one year after surgery.

Methods: EndoQUEST is a longitudinal cohort study of 90 participants with surgically-confirmed endometriosis aged 12-23 years old at the time of their endometriosis-related surgery. Participants completed an expanded WERF EPHect questionnaire prior to and one year after their index surgery. For this analysis, we conservatively defined pain remediation as a reduction in both frequency and severity of dysmenorrhea and acyclic pelvic pain at one-year post-surgery relative to their pre-surgical report. We used age-adjusted logistic regression to compare pre-surgical characteristics between those with and without pain remediation one year after surgery. This study as approved by the local IRB.

Results: Median age at endometriosis-focused surgery was 16 years (interquartile range=15-18 years) and 93% identified as White race. Of the 90 participants, 23 (26%) reported both dysmenorrhea and acyclic pain improvement at one year after their index surgery. Compared to those whose dysmenorrhea and/or acyclic pain did not improve, those with improved pain were more likely to report lower pain catastrophizing (e.g., pain-related worry) scale scores (mean[SD]=17.9[14.7] vs 26.0[11.7]; p=0.04). Those who demonstrated pain improvement one year post-surgery experienced less frequent (reported weekly or daily pain (22% vs. 77%; p=0.01)) and less severe (numeric pain rating scale (mean[SD]=6.6[2.3] vs. 7.9[1.9]; p=0.09) acyclic pelvic pain prior to surgery compared to those whose pain did not improve. Further, those with pain improvement reported less life interference due to acyclic pelvic pain and/or dysmenorrhea prior to surgery (57% vs. 87%; p=0.009).

Conclusions: Pre-surgical pain severity and frequency as well as burdensome concerns about pain were associated with improvement in dysmenorrhea and acyclic pelvic pain one year after endometriosis-focused surgery. These results are consistent with predictors of post-surgical pain persistence in adults and support continued exploration and establishment of nociceptive versus nociplastic pain categorization of patient treatment decision trees.