Association of Serum IL-6 (Interleukin 6) With Functional Outcome After Intracerebral Hemorrhage.

Abstract

IL-6 (interleukin 6) is a proinflammatory cytokine and an established biomarker in acute brain injury. We sought to determine whether admission IL-6 levels are associated with severity and functional outcome after spontaneous intracerebral hemorrhage (ICH). We performed an exploratory analysis of the recombinant activated FAST trial (Factor VII for Acute ICH). Patients with admission serum IL-6 levels were included. Regression analyses were used to assess the associations between IL-6 and 90-day modified Rankin Scale. In secondary analyses, we used linear regression to evaluate the association between IL-6 and baseline ICH and perihematomal edema volumes. Of 841 enrolled patients, we included 552 (66%) with available admission IL-6 levels (mean age 64 [SD 13], female sex 203 [37%]). IL-6 was associated with poor outcome (modified Rankin Scale, 4-6; per additional 1 ng/L, odds ratio, 1.30 [95% CI, 1.04-1.63]; <i>P</i>=0.02) after adjustment for known predictors of outcome after ICH and treatment group. IL-6 was associated with ICH volume after adjustment for age, sex, and ICH location, and this association was modified by location (multivariable interaction, <i>P</i>=0.002), with a stronger association seen in lobar (β, 12.51 [95% CI, 6.47-18.55], <i>P</i><0.001) versus nonlobar (β 5.32 [95% CI, 3.36-7.28], <i>P</i><0.001) location. IL-6 was associated with perihematomal edema volume after adjustment for age, sex, ICH volume, and ICH location (β 1.22 [95% CI, 0.15-2.29], <i>P</i>=0.03). Treatment group was not associated with IL-6 levels or outcome. In the FAST trial population, higher admission IL-6 levels were associated with worse 90-day functional outcome and larger ICH and perihematomal edema volumes.