Correlation among systemic inflammatory parameter, occurrence of delayed neurological deficits, and outcome after aneurysmal subarachnoid hemorrhage

Abstract

Background: The role and impact of systemic inflammatory response after aneurysmal subarachnoid hemorrhage remain to be elucidated.

Objective: To assess the time course and correlation of systemic inflammatory parameters with outcome and the occurrence of delayed ischemic neurological deficits (DINDs) after subarachnoid hemorrhage.

Methods: Besides the baseline characteristics, daily interleukin-6 (IL-6), procalcitonin, C-reactive protein levels, and leukocyte counts were prospectively measured until day 14 after subarachnoid hemorrhage. Occurrence of infectious complications and application of therapeutic hypothermia were assessed as confounding factors. The primary end point was outcome after 3 months, assessed by Glasgow outcome scale; the secondary end point was the occurrence of DINDs.

Results: During a 3-year period, a total of 138 patients were included. All inflammatory parameters measured were higher in patients with unfavorable outcome (Glasgow outcome scale score, 1-3). After adjustment for confounding factors, elevated IL-6 and leukocyte counts remained significant risk factors for unfavorable outcome. The odds ratio for log IL-6 was 4.07 (95% confidence interval, 1.18 to 14.03; P = .03) and for leukocyte counts was 1.24 (95% confidence interval, 1.06-1.46, P = .008). The analysis of the time course established that IL-6 was the only significantly elevated parameter in the early phase in patients with unfavorable outcome. Higher IL-6 levels in the early phase (days 3-7) were associated with the occurrence of DINDs. The adjusted odds ratio for log IL-6 was 4.03 (95% confidence interval, 1.21-13.40; P = .02).

Conclusion: Higher IL-6 levels are associated with worse clinical outcome and the occurrence of DINDs. Because IL-6 levels were significantly elevated in the early phase, they might be a useful parameter to monitor.