Prognostic value of systemic immune-inflammation index and systemic inflammation response index with maternal gestational diabetes mellitus: A systematic review and meta-analysis.

OBJECTIVE: Mounting evidence indicates that the systemic immune-inflammation index (SII) and systemic inflammation response index (SIRI) might be associated with the risk of gestational diabetes mellitus (GDM). However, existing findings remain inconclusive. This systematic review and meta-analysis aimed to elucidate the associations of SII and SIRI with clinical outcomes in patients with GDM and quantitatively evaluate the SII and SIRI values in GDM patients. METHOD: A systematic literature search was conducted in four major electronic databases: PubMed, Embase, Web of Science, and the Cochrane Library. The search covered all studies published from the inception of each database up to April 15, 2025. The search strategy combined keywords and subject terms related to, for instance, "GDM," "SII," and "SIRI." Cohort and case-control studies investigating the associations of SII and/or SIRI with clinical outcomes (e.g., glycemic control, maternal and infant complications) in GDM patients were eligible for inclusion. Reviews, case reports, animal studies, and studies with insufficient data were excluded. After relevant data had been extracted from the eligible studies, meta-analyses were conducted using appropriate effect measures. For dichotomous outcomes, pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. For continuous outcomes, including SII and SIRI values, pooled standardized mean differences (SMDs) with 95% CIs were estimated. Sensitivity analyses were performed to evaluate the robustness of the findings and to explore potential sources of between-study heterogeneity. RESULTS: Nine studies involving 67 068 participants were included. Meta-analysis showed that higher SII levels were significantly associated with an increased risk of GDM in both continuous (SMD = 0.13, 95% CI: 0.04-0.21; P < 0.05) and categorical analyses (OR = 1.10, 95% CI: 1.03-1.17; P = 0.006). Similarly, elevated SIRI levels were associated with a higher risk of GDM in both continuous (SMD = 0.18, 95% CI: 0.00-0.36; P = 0.05) and categorical analyses (OR = 1.20, 95% CI: 1.12-1.28; P < 0.00001). Substantial between-study heterogeneity was observed. Sensitivity analyses demonstrated the robustness of the associations for continuous and categorical SII measures and for categorical SIRI measures. In contrast, the association between continuous SIRI and GDM was less stable. CONCLUSION: Elevated SII and SIRI values were associated with an increased risk of developing GDM, suggesting that these indices might serve as valuable biomarkers for GDM prediction. These findings provide an important foundation for the early identification and prevention of GDM.