Estimating the prognosis of patients with spontaneous subarachnoid hemorrhage (SAH) early after SAH remains difficult. Hunt&Hess (H&H) as well as WFNS score were shown to have good discriminatory abilities. However, peripheral organ complications are not reflected in these scores. The sequential organ failure assessment score (SOFA) is used in intensive care units (ICU) to monitor organ dysfunction, and it was shown to predict outcome of SAH patients on ICU with similar predictive values as WFNS and H&H. The aim of our study was to determine the most robust prediction parameters for outcome within the SOFA score and to develop a simplified new score.

We retrospectively evaluated all SAH patients admitted to our neurosurgical ICU during a 10-year period. Inclusion criteria were availability of clinical data on HH and WFNS scores, SOFA score day 1 after hospital admission, modified Rankin scale (mRS) after 6 months, and a CT scan 14-28 days post-SAH to evaluate DCI-associated infarctions. Each parameter of the SOFA score (GCS, arterial blood pressure, Horovitz quotient, creatinine and bilirubin levels, and platelet counts) was graded for its predictive value and combinations were tested using ROC analysis and Youden Index (YI).

253 patients with complete necessary data were included; 71.4% were female; mean age was 57.13±12.5 years. Median SOFA score was 4, median H&H score was 3, median WFNS score was 3. Towards predicting unfavorable outcome (mRS 4-6), AUC for SOFA was 0.77 (CI95%=0.71-0.82), YI of 0.39 at a cut off of ≥7 points. For the HH score AUC was 0.73 (CI95%=0.67-0.8), YI 0.37 with a cut off at ≥ 2, and for WFNS score AUC was 0.71 (CI95%=0.65-0.77), YI of 0.36 with the cut off at ≥ 2. Of the parameters within the SOFA score, GCS, mean arterial blood pressure (MAP) and Horovitz quotient (paO2/fiO2) were most reliable. A score combining exclusively these factors (0-4 points per parameter in analogy to the SOFA score) yielded an AUC of 0.79 (CI95%=0.73-0.84) with a YI of 0.43 at a cut off at ≥5 points (PPV 0.53, NPV 0.99, sensitivity 0.99, specificity 0.45).

A simplified SOFA score, including GCS, the MAP and the Horovitz quotient – which are regularly documented in intensive care medicine and therefore available for SAH patients treated on the ICU – predicted neurological outcome better than the established H&H and WFNS scores. It could therefore provide additional information to select SAH patients at risk for unfavorable outcome.