Systemic immune-inflammation indices and pelvic pain burden in endometriosis: Added value of PIV over conventional ratios

Aim: Endometriosis is an estrogen-dependent gynecologic disorder that often presents with pain. Objective and easily accessible biomarkers for assessing pain remain limited. This study aimed to evaluate the association between systemic inflammatory indices including neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), and pan immune inflammation value (PIV) and pelvic pain in women with endometriosis. Materials and Methods: This retrospective study included 104 women with surgically and/or radiologically confirmed endometriosis. Patients were categorized according to the presence of clinically significant pelvic pain. Demographic characteristics, complete blood count parameters, inflammatory indices (NLR, PLR, PIV), and revised American Society for Reproductive Medicine (rASRM) scores were compared between groups. A logistic regression model was performed to find predictors of pelvic pain. Results: Pelvic pain was present in 73 patients (70.2%), while 31 patients (29.8%) reported no pain. Age and absolute neutrophil, lymphocyte, and platelet counts were similar between the groups. Patients with pelvic pain exhibited significantly higher mean NLR (2.01±0.95 vs. 1.56±0.75, p=0.012), PLR (130.6±41.5 vs. 111.1±35.3, p=0.017), and PIV values (421±101.8 vs. 355±114.1, p=0.007). The rASRM score was significantly higher in patients with pelvic pain (17.0±13.2 vs. 5.0±5.3, p< 0.001). In multivariable analysis, PLR (OR=1.03, 95% CI: 1.01–1.05, p=0.004), PIV (OR=1.01, 95% CI: 1.00–1.01, p=0.008), and rASRM score (OR=1.16, 95% CI: 1.07–1.26, p< 0.001) were identified as independent predictors of pelvic pain, whereas NLR did not. Conclusion: PLR and PIV are independently associated with pelvic pain in endometriosis, alongside disease severity. These readily available inflammatory markers may serve as adjunctive tools in clinical pain assessment.