Association of platelets and platelet-related parameters (PLT/MPV/PLR) in endometriosis: a meta-analysis

BACKGROUND: Endometriosis (EMS) is a prevalent gynecological condition, and its diagnosis remains challenging. Hematological indicators such as platelet count (PLT), mean platelet volume (MPV), and platelet-to-lymphocyte ratio (PLR) have recently received attention for their potential diagnostic value in EMS. OBJECTIVE: To assess the association of PLT, MPV, and PLR in EMS by a meta-analysis. METHODS: We systematically searched Embase, PubMed, Cochrane Library, and Web of Science up to June 2025 for studies on the association of platelet-related parameters (PLT, MPV, and PLR) with EMS. Standardized mean difference (SMD) with 95% confidence interval (CI) was calculated for PLT, MPV, and PLR using a random-effects model. All statistical analyses were performed using Stata16.0. RESULTS: Nineteen studies with 5675 subjects were included. Overall pooled analyses showed no statistically significant differences in PLT (SMD 0.35 [- 0.02, 0.71], I²=97.6%, P = 0.063) and PLR (SMD 0.24 [- 0.16, 0.64], I²=96.6%, P = 0.224) between EMS and non-EMS populations. However, MPV was significantly elevated in EMS compared with non-EMS populations (SMD 0.30 [0.09, 0.52], I²=82.7%, P = 0.006). Subgroup analyses by control group type revealed context-dependent associations. Compared with benign gynecological conditions (e.g., ovarian cysts, uterine fibroids), EMS showed significantly elevated PLT (SMD 0.20 [0.01, 0.38], I²=53.7%, P = 0.042) and PLR (SMD 0.33 [0.22, 0.43], I²=0.0%, P < 0.01). PLT was significantly lower in EMS than in ovarian cancer (SMD - 0.56 [- 0.81, - 0.32], I²=0.0%, P < 0.001). MPV was significantly elevated in EMS compared with healthy individuals (SMD 0.46 [0.11, 0.81], I²=84.7%, P = 0.010), whereas no significant difference was observed between EMS and other benign gynecological conditions (SMD 0.04 [- 0.10, 0.19], I²=0.0%, P = 0.547). CONCLUSION: MPV shows potential as an adjunctive marker for EMS, while PLT and PLR have limited independent diagnostic value but may be useful in specific clinical contexts.