# CLR (C-Reactive Protein to Lymphocyte Ratio) Served as a Promising Predictive Biomarker for Cerebral Vasospasm in Aneurysmal Subarachnoid Hemorrhage (aSAH): A Retrospective Cohort Study

## TL;DR

This study shows that a blood test called CLR can predict dangerous brain complications after a type of brain hemorrhage.

## Contribution

CLR is identified as a novel, easily measurable biomarker for predicting cerebral vasospasm after aneurysmal subarachnoid hemorrhage.

## Key findings

- High CLR levels on admission are independently linked to cerebral vasospasm and delayed cerebral ischemia after aSAH.
- CLR has a 77.1% sensitivity and 75.4% specificity for predicting cerebral vasospasm.
- A CLR cutoff of 0.757 mg × 10−6 effectively distinguishes patients who will develop cerebral vasospasm.

## Abstract

Background: Subarachnoid hemorrhage is a devastating disease. Even after state-of-the-art treatment patients suffer from complications, including cerebral vasospasm (CVS), delayed cerebral ischemia (DCI), and chronic hydrocephalus (CH) following aneurysmal subarachnoid hemorrhage (aSAH). The aim of our study is to identify the predictive value of the C-reactive protein to lymphocyte ratio (CLR) for neurological functional outcome and complications after aSAH. Methods: We retrospectively analyzed a total of 166 aSAH patients who met the inclusion criteria enrolled in our study. Multivariate logistic regression analyses were performed to evaluate the independent risk factors. The predictive value of different models was compared by calculating the areas under the receiver operating characteristic (ROC) curve. Results: On-admission levels of CLR in patients with poor outcomes (6 months mRS 3–6), CVS, DCI, and CH were significantly higher than those in patients with good outcomes (6 months mRS 0–2), non-CVS, non-DCI, and non-CH. Multivariate logistic regression analysis revealed that admission CLR was independently associated with CVS (OR [95% CI] 2.116 [1.507–2.971]; p < 0.001), and DCI (OR [95% CI] 1.594 [1.220–2.084]; p = 0.001). In ROC analysis, the area under the curve (AUC) of CLR for poor outcomes (6 months mRS 3–6), CVS, DCI, and CH prediction were (AUC [95% CI] 0.639 [0.555–0.724]; p = 0.002), (AUC [95% CI] 0.834 [0.767–0.901]; p < 0.001), (AUC [95% CI] 0.679 [0.581–0.777]; p < 0.001), and (AUC [95% CI] 0.628 [0.543–0.713]; p = 0.005) revealing that admission CLR had a favorable predictive value for CVS after aSAH. The sensitivity and specificity of admission CLR for CVS prediction were 77.1% and 75.4%. On-admission CLR of 0.757 mg × 10−6 was identified as the best cutoff threshold to discriminate between CVS and non-CVS (CVS: CLR < 0.757 mg × 10−6 11/100 [11.0%] vs. CLR ≥ 0.757 mg × 10−6 37/66 [56.1%]; p < 0.001). Conclusions: High levels of on-admission CLR serve as an independent risk factor for CVS and DCI after aSAH. Admission CLR is an easy-to-quantify laboratory parameter that efficiently predicts the CVS after aSAH, which can provide some guidance for clinicians to evaluate for possible progression and treatment strategies in patients with aSAH.