# Association between systemic inflammation biomarkers and outcomes in patients with aneurysmal subarachnoid hemorrhage

## TL;DR

This study shows that higher levels of systemic inflammation biomarkers CRP and NLr are linked to worse outcomes in patients with aneurysmal subarachnoid hemorrhage.

## Contribution

The study demonstrates that CRP and NLr are independently associated with unfavorable neurological outcomes and delayed cerebral ischemia in aSAH patients.

## Key findings

- Elevated CRP levels from days 2 to 7 after SAH were independently linked to unfavorable outcomes.
- Higher NLr values were associated with both unfavorable outcomes and delayed cerebral ischemia.
- CRP and NLr levels reinforce inflammation's role in secondary brain injury after aSAH.

## Abstract

Aneurysmal subarachnoid hemorrhage (aSAH) is a devastating condition that is associated with cerebral and systemic inflammation. C-reactive protein (CRP) and neutrophil-to-lymphocyte ratio (NLr) are easily available biomarkers of systemic inflammation. Therefore, we aimed to assess the impact of elevated CRP and NLr on aSAH outcomes. This retrospective, single-center study included adult patients admitted with aSAH to the intensive care unit (ICU) from January 2007 to December 2023. We recorded serum CRP and NLr levels during the first 7 days of ICU stay. An unfavorable neurological outcome at 3 months was defined as a Glasgow Outcome Scale (GOS) score of 1–3. A total of 547 patients were included in the study; 250 (45.7%) experienced unfavorable outcomes (UOs), and 140 (25.6%) developed delayed cerebral ischemia (DCI). Patients with unfavorable outcomes had higher levels of CRP from days 2 to 7 after SAH (p = 0.001) and higher NLr (p = 0.06) than those with favorable outcomes (FOs). In a multivariate logistic regression model, the highest CRP value (OR: 1.003, 95% CI: 1.001–1.005) and the highest NLr value (OR: 1.025; 95% CI: 1.001–1.050) in the first 7 days after SAH were independently associated with the occurrence of unfavorable outcomes. The highest NLr value was also associated with the development of DCI (sHR: 1.02, 95% CI: 1.01–1.03). In conclusion, high CRP and NLr values have a significant prognostic role in aSAH patients, reinforcing the importance of inflammation as a potential mechanism of secondary brain injury.