The association between systemic immune-inflammation index and post-stroke depression: a meta-analysis

Post-stroke depression (PSD) is a common neuropsychiatric complication that adversely affects recovery and prognosis after stroke. The systemic immune-inflammation index (SII), a composite biomarker derived from peripheral blood counts, reflects systemic inflammatory status and has been associated with adverse neurological outcomes. However, the relationship between SII and PSD remains uncertain. We conducted a meta-analysis to clarify this association.

PubMed, Embase, Web of Science, Wanfang, and CNKI were searched for observational studies evaluating the association between SII and PSD in adult stroke patients. Odds ratios (ORs) with 95% confidence intervals (CIs) were pooled using a random-effects model by incorporating the potential influence of heterogeneity.

Seven studies involving 2,780 patients were included, among whom 822 developed PSD. Compared with lower SII levels, high SII at admission was significantly associated with an increased risk of PSD (OR = 2.14, 95% CI: 1.74-2.64; I² = 22%). Sensitivity analyses by excluding one study at a time showed similar results (pooled OR range: 2.06-2.38, all p-values < 0.05), which confirmed the stability of the findings. The association remained consistent across study design, stroke type, age, sex proportion, SII cutoff method, cutoff value, PSD assessment tool, and study quality (all p for subgroup differences > 0.05).

Elevated SII may be independently associated with an approximately twofold increased risk of PSD. SII may serve as a simple and accessible inflammatory biomarker for early identification of patients at higher risk of developing PSD.

https://www.crd.york.ac.uk/prospero/, identifier CRD420261326749.