Clinical Usefulness of Early Serial Measurement of C-Reactive Protein as Outcome Predictors in Patients with Subarachnoid Hemorrhage

Background: The purpose of this study was to evaluate the role of C-reactive protein (CRP) in predicting neurological outcomes of patients with subarachnoid hemorrhage (SAH). Methods: This was a retrospective, single-center, observational study of adult patients with SAH admitted January 2012 through June 2017. We included patients with initial CRP levels collected within 24 hours from onset of SAH and with follow-up CRP levels. Primary outcome was neurological status at six-month follow-up assessed with the Glasgow Outcome Scale (GOS, 1 to 5). Results: Among 156 SAH patients, 145 (92.9%) survived until discharge. Of these survivors, 109 (69.9%) manifested favorable neurological outcomes (GOS of 4 or 5). CRP levels progressively increased from admission to the third or fourth day, followed by slow decrease toward the seventh day. Levels of initial CRP on admission and maximal CRP within four days in the poor neurological outcome group were significantly greater than in the favorable outcome group (P = 0.022, P < 0.001, respectively). However, clearance of CRPs did not differ significantly between the two groups (P = 0.785). Analysis of the receiver operating characteristic curve for prediction of poor neurological outcome showed that the performance of maximal CRP was significantly better than that of initial CRP and clearance of CRPs (P = 0.007, P < 0.001, respectively). In this study, we found that the effect of CRP on the neurological outcome differed by surgical clipping. Multivariable logistic regression analysis revealed that age (adjusted odd ratio [OR]: 1.10, 95% confidence interval [CI]: 1.052 – 1.158), initial Glasgow Coma Scale (adjusted OR: 0.74, 95% CI: 0.647 – 0.837) and maximal CRP without surgical clipping (adjusted OR: 1.27, 95% CI: 1.066 – 1.516) were significantly associated with poor neurological outcomes in SAH patients. However, maximal CRP with surgical clipping (adjusted OR: 1.01, 95% CI: 0.840 – 1.223) was not associated with poor neurological outcomes of SAH patients. Conclusions: Early serial measurement of CRP may be used to predict neurological outcomes of SAH patients. Furthermore, maximal CRP levels within four days after SAH are significantly associated with poor neurological outcomes.