Serum Levels of Myo-inositol Predicts Clinical Outcome 1 Year After Aneurysmal Subarachnoid Hemorrhage

BACKGROUND: Early prognostication of long-term outcome in patients suffering from spontaneous subarachnoid hemorrhage (SAH) remains a challenge. No biomarkers are routinely used for prognostication. A previous study has indicated that the metabolite myo-inositol (MI) may be used to predict long-term outcome. OBJECTIVE: To investigate if MI measured in serum correlates with long-term clinical outcome in patients suffering from SAH. METHODS: We conducted an observational cohort study including 88 patients treated for SAH at Umeå University Hospital. Serum samples were collected in the hospital, and a gas chromatography/mass spectroscopy method was used to quantitatively measure MI. Patients were assessed after 1 year using the Glasgow Outcome Scale Extended and dichotomized to favorable or unfavorable outcome. Differences in MI levels between the 2 groups were analyzed. RESULTS: There was no difference in MI levels between the groups upon admission. Myo-inositol levels decreased over time in the entire study population. The decrease was significantly larger in the unfavorable outcome group. A receiver operating characteristics analysis yielded an area under the curve of 0.903 (CI 0.8-1.0, P < .001) for the MI value on day 7 to predict favorable outcome after 1 year. CONCLUSION: Myo-inositol measured in serum may aid prognostication of outcome in patients with SAH. The mechanism behind this remains unclear, although it can be theorized to reflect processes leading to delayed cerebral ischemia, which affects long-term outcome. This is the first study to quantitively measure MI in serum for prognostication of outcome in patients with SAH.