Predicting mortality in subarachnoid haemorrhage based on first-week routine blood tests

Accurate prognosis of outcome in subarachnoid haemorrhage (SAH) identifies salvageable poor-grade patients. Widely available and independent prognostic factors are needed, thus value of six routine blood tests is established. Prospectively collected database of 116 aneurysmal SAH patients was reviewed for white blood cell (WBC) count and concentration of C-reactive protein (CRP), sodium, potassium, glucose and haemoglobin on day 0, 1, 2, 3-4 and 5-7 post-SAH. All patients were admitted within 24 h, treated endovascularly within 48 h and assessed neurologically at admission and at three months post-SAH. Multivariate logistic regression and receiver operating curve were analyzed for each type of parameter assessed on specific day post-SAH. We have identified three different types of blood tests with the largest area under the curve (AUC). The three types of parameters identified as the most accurate, independent prognostic factors for mortality are WBC count on day 1 (p < 0.01 with AUC of 0.82); sodium level on day 2 (p < 0.05 with AUC of 0.81) and CRP level on day 3-4 (p < 0.05 with AUC of 0.74). Cut-off values of 12.88 × 10³/µl, 155 mmol/l and 142.7 mg/l (respectively) exceeded on indicated time points predict patient's death with 96.7% specificity and 68.8% sensitivity. Early alterations in routine blood tests provide an accurate prognosis of death in SAH independently from well-established prognostic tools.