In patients with brainstem hemorrhage, SII is markedly elevated in the early phase with a dynamic pattern of rapid rise on day 1, peak on day 3, and gradual decline by day 7, and high SII is closely associated with increased mortality and poor functional outcomes, suggesting that SII can serve as an early prognostic biomarker.
Key Findings
Results
SII followed a characteristic dynamic pattern in brainstem hemorrhage patients, rising rapidly by day 1, peaking on day 3, and declining by day 7.
SII was calculated from complete blood counts on days 1, 3, and 7 after admission in 140 patients with brainstem hemorrhage
The linear mixed-effects model revealed a significant group-by-time interaction (p < 0.001)
The high-SII group demonstrated a more intense and slower-resolving inflammatory response compared to the low-SII group
Patients were divided into high and low SII groups based on the median SII on day 1
Results
The high-SII group had significantly higher rates of 90-day poor functional outcome and 30-day mortality compared to the low-SII group.
90-day poor functional outcome rate was significantly higher in the high-SII group (p < 0.001)
30-day mortality was significantly higher in the high-SII group (p = 0.004)
Functional outcome was assessed using the 90-day modified Rankin Scale (mRS) score
The study enrolled 140 patients with brainstem hemorrhage admitted to the Department of Neurosurgery
Results
Day 3 SII was identified as an independent predictor of both 90-day poor functional outcome and 30-day mortality in multivariable logistic regression.
Day 3 SII independently predicted 30-day mortality (p < 0.001)
Multivariable logistic regression controlled for demographic data, medical history, admission GCS score, and blood pressure
Day 3 SII showed stronger predictive association than Day 1 SII in the multivariable models
Results
ROC analysis demonstrated that Day 3 SII had strong predictive performance for 30-day mortality, which was further improved in a combined model.
Day 3 SII alone predicted 30-day mortality with an AUC of 0.878
A combined model incorporating Day 3 SII with other variables achieved an AUC of 0.920 for 30-day mortality prediction
ROC curve analysis was used to evaluate predictive performance
Methods
The study was a retrospective analysis of brainstem hemorrhage patients, a severe subtype of spontaneous intracerebral hemorrhage characterized by high mortality and disability rates.
140 patients with brainstem hemorrhage were retrospectively enrolled from the Department of Neurosurgery
SII was calculated as a comprehensive inflammatory marker reflecting the balance between immunity and inflammation
SII is derived from complete blood count components
Outcomes included 30-day mortality, 90-day mRS score, and complications
What This Means
This research suggests that a blood test measurement called the Systemic Immune-Inflammation Index (SII) — calculated from a standard complete blood count — can help predict which patients with brainstem hemorrhage are at greatest risk of dying or having poor recovery. In a study of 140 patients, researchers found that SII rises sharply within the first day after a brainstem bleed, peaks around day 3, and then gradually falls by day 7. Patients with higher SII levels experienced significantly more deaths within 30 days and worse functional ability at 90 days compared to patients with lower SII levels.
The day 3 SII measurement was particularly informative — it independently predicted both death and poor functional outcome even after accounting for other clinical factors. When combined with other clinical information, the day 3 SII achieved a very high accuracy (AUC of 0.920) for predicting 30-day mortality, suggesting it captures meaningful information about the severity of the body's inflammatory response following a brainstem bleed.
This research suggests that routinely tracking SII in the first week after brainstem hemorrhage could help clinicians identify high-risk patients earlier and potentially guide treatment decisions. Because SII is derived from a standard blood test already commonly performed in hospital settings, it could be a practical and cost-effective tool for risk stratification. Future prospective studies would be needed to confirm these findings and determine whether early intervention targeting the inflammatory response could improve patient outcomes.
He S, Zhang Y, Wei W, Shi H, Qin R, Yu Z, et al.. (2026). Early systemic immune-inflammation index is associated with mortality and functional outcome in brainstem hemorrhage.. Frontiers in neurology. https://doi.org/10.3389/fneur.2026.1879981