Patients with endometriosis can be categorized into two distinct pain phenotypes, with one group experiencing significantly higher symptom severity, more comorbidities, and poorer quality of life, according to a recent study.

In the cross-sectional, population-based study, published in BJOG: An International Journal of Obstetrics and Gynaecology, investigators examined pain phenotypes in patients with endometriosis. The study utilized latent class analysis (LCA) to identify pain phenotypes and assess their associations with demographics, clinical characteristics, comorbidities, and pain-related quality of life (QoL).

The investigators included 352 participants aged 18 to 50 years, consecutively enrolled from January 2020 to April 2024. Data collection involved validated instruments, including the Endometriosis Health Profile-30 (EHP-30) and Pain Quality Assessment Scale. LCA identified two distinct pain phenotypes: a high pain phenotype (54%, n = 189) and a low pain phenotype (46%, n = 163).

The high pain phenotype exhibited significantly higher frequencies and severities of symptoms such as dysmenorrhea (mean score = 6.7 ± 3.5) and deep dyspareunia (mean score = 6.5 ± 2.7) compared with the low pain group (mean dysmenorrhea score = 3.8 ± 3.3, mean deep dyspareunia score = 4.0 ± 3.2). QoL scores were notably poorer in the high pain group, with a mean EHP-30 pain subscale score of 59 (95% confidence interval [CI] = 56–62) compared with 33 (95% CI = 29–37) in the low pain group (P < .001).

The high pain group was associated with greater treatment failures (odds ratio [OR] = 2.09, 95% CI = 1.29–3.39), higher prevalence of comorbidities such as migraines (51% vs 37%), fibromyalgia (11% vs 4%), and irritable bowel syndrome (39% vs 17%), and increased use of painkillers within the past 3 months (78% vs 51%). A family history of endometriosis or chronic pelvic pain was also predictive of this pain phenotype (OR = 1.94, 95% CI = 1.17–3.22).

In contrast, the low pain phenotype was associated with a higher prevalence of endometrioma (34% vs 24%, OR = 0.56, 95% CI = 0.33–0.95).

The study concluded that LCA identified distinct pain phenotypes in endometriosis, which were associated with patient characteristics and QoL. The researchers noted the need for further validation in diverse populations.

Full disclosures can be found in the published study.