Systemic immune-inflammation index and risk of gestational diabetes and preeclampsia: a systematic review and meta-analysis.

Background: The systemic immune-inflammation index (SII) has been a marker and prognostic indicator of several diseases. However, its utility in pregnancy is unknown. Herein, we reviewed the evidence on the ability of SII to predict gestational diabetes mellitus (GDM) and preeclampsia (PE).

Methods: A systematic search of PubMed, Embase, Scopus and Web of Science was conducted for studies comparing SII between GDM/PE and non-GDM/non-PE groups. Studies reporting diagnostic accuracy data were also included. The last date of the search was 5 November 2024. Risk of bias was assessed using Newcastle Ottawa Scale. Random-effect meta-analysis was conducted comparing values of SII between GDM/PE and non-GDM/non-PE groups.

Results: Nine studies were eligible. Four studies reported data on GDM and five on PE. Most studies measured SII in the first trimester. The pooled analysis showed no statistically significant difference in the SII values between PE and non-PE groups (MD: 13.07, 95% confidence interval (CI): -117.21, 143.35, I² = 78%). Meta-analysis of four studies comparing data of GDM and non-GDM groups showed that SII was significantly higher in GDM females (MD: 210.32, 95% CI: 57.3, 363.34, I² = 94%). The sensitivity of SII to predict PE varied from 40 to 77.5% while specificity varied from 53.8 to 67.5%. For studies on GDM, the sensitivity and specificity values varied from 66 to 80.2% and 34.4 to 65%, respectively.

Conclusions: SII values are significantly higher in GDM compared to non-GDM females. However, SII values did not correlate with PE. SII may have potential in predicting GDM which needs to be explored by further studies.