Association of Systemic Inflammatory Biomarkers (NLR, MLR, PLR, SII, SIRI) with Preeclampsia-Related Kidney Injury: A Retrospective Observational Study.

Abstract

Background: Approximately 7-13% of pregnant women with preeclampsia (PE) develop acute kidney injury (AKI), which is one of the most serious complications of PE and is linked to long-term chronic kidney disease. This retrospective observational study investigated the association between inflammation indices and PE-related acute kidney injury (PE-AKI).

Methods: This retrospective study analyzed 4071 PE patients admitted between 2013 and 2023. Inflammatory indices, including neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), platelet-to-lymphocyte ratio (PLR), systemic immune-inflammation index (SII), and systemic inflammation response index (SIRI), were derived from complete blood counts. Multivariate logistic regression assessed associations with PE-AKI risk, with nonlinear relationships characterized using restricted cubic spline models.

Results: Among 4071 patients with PE, 290 (7.13%) developed AKI. Multivariate analysis (Model 3) revealed significant positive associations between log₂-transformed inflammatory indices and PE-AKI risk, with the highest odds ratios observed for MLR (OR = 6.02, 95% CI: 4.68-7.73; P < 0.0001) and NLR (OR = 3.93, 95% CI: 3.09-5.01; P < 0.0001). MLR demonstrated the strongest independent correlation with PE-AKI (highest tertile OR = 7.24, 95% CI: 4.75-11.02), followed by SIRI (OR = 5.78, 95% CI: 3.89-8.59). All indices (NLR, MLR, PLR, SII, SIRI) exhibited linear dose-response relationships with PE-AKI risk (P-overall <0.001 for each). Subgroup analyses further identified elevated MLR as a prominent risk factor in early-onset PE (gestational age ≤32 weeks; OR = 8.81, 95% CI: 4.91-17.10) and patients with complications (OR = 7.28, 95% CI: 5.23-10.32).

Conclusion: MLR and SIRI are positively associated with PE-AKI risk, particularly in early-onset and complicated cases. This first comprehensive assessment of five biomarkers supports clinical utility. Prospective validation is required, with focus on monocyte-mediated inflammatory mechanisms.