Improving health-related quality of life in patients with endometriosis-related chronic pain: The COGENS trial

Research Question: Endometriosis-related chronic pain leads to impaired health-related quality of life (HRQoL). Endometriosis surgery can improve chronic pain and HRQoL, but not to the same level as healthy women. Cognitive behavioral therapy (CBT) is promising for the treatment of chronic pain. In this study we evaluate the effect of CBT on HRQoL in patients undergoing surgery for endometriosis-related chronic pain. Design: This randomized controlled, single-blind multicenter, clinical trial, 100 Dutch patients undergoing surgery for endometriosis related chronic pain were included. Participants were randomized between endometriosis surgery only or endometriosis surgery plus the intervention: seven sessions of CBT. Questionnaires evaluated HRQoL, pain intensity, catastrophizing, anxiety, fatigue, and perceived stress four weeks prior to surgery (T0), and two (T1) and 16 (T2) weeks after the final CBT session. Hair cortisol concentrations (HCC) were analyzed to measure chronic stress. Group differences were evaluated with linear mixed models. Results Inclusion occurred between November 24, 2020 and December 28, 2023. The intention to treat analysis included 100 patients, 50 in each group. In the CBT group, the Endometriosis Health Profile (EHP)-30 modular part (p = .021) and the Short Form (SF)-36 physical component scale (p = .008) improved more when compared to the surgery-only group. Pain catastrophizing (p = .019) and anxiety (p = .047) were significantly lower in patients who were in the CBT group. The EHP-30 core part, SF-36 mental component scale, pain intensity, fatigue, perceived stress, and HCC. Conclusions CBT can improve HRQoL in patients surgically treated for endometriosis-related chronic pain. The reduction of pain catastrophizing was a major factor in this effect. Trial register ClinicalTrials.gov NCT04448366. Registered on June 3th, 2020. First participant enrollment: 24-11-2020. https://clinicaltrials.gov/study/NCT04448366?cond=NCT04448366&rank=1. The data generated and analyzed during the current study are available at Radboud Data Repository. The data can be accessed via https://doi.org/10.34973/fqsc-wd42. Data will be available for academic and non-commercial purposes upon reasonable request, starting one year after publication date.