Potential role of serum substance P as a favorable biomarker of functional outcome in acute spontaneous intracerebral hemorrhage.

Background: Substance P (SP) is implicated in brain inflammation. We clarified relationship between serum SP concentrations and functional outcome of acute intracerebral hemorrhage (ICH).

Methods: We quantified admission serum SP concentrations in 106 ICH patients. The primary outcome measure was a poor outcome at 90 days (modified Rankin Scale score ≥ 3) after onset.

Results: Patients with a poor outcome compared with the rest had substantially higher serum SP concentrations. The area under the curve for serum SP concentrations with regard to discriminating a poor outcome was 0.795 (95% CI, 0.706 to 0.867). Serum SP concentrations >449 pg/ml predicted the risk of a poor outcome with 63.0% sensitivity and 78.9% specificity, and were independently associated with a poor outcome (odds ratio, 5.437; 95% CI, 2.156 to 13.715). There were the positive associations between serum SP concentrations, National Institutes of Health Stroke Scale score (r = 0.480), hematoma volume (r = 0.464) and serum C-reactive protein concentrations (r = 0.398).

Conclusions: Higher serum SP concentrations in the acute phase of ICH were intimately associated with aggravated inflammation response, rising severity and increased risk of a poor functional outcome, suggesting that serum SP could be an inflammatory prognostic factor for ICH.