Elevated blood glucose is frequently detected early after aneurysmal subarachnoid hemorrhage (aSAH) and is considered a risk factor for poor neurological outcome. However it remains unclear whether hyperglycemia is caused by the SAH ictus or reflects a pre-existing hyperglycemic metabolism. In a prospective register Beseoglu and Steiger analysed glycated hemoglobin levels (HbA1c) in patients with aSAH and its influence on outcome ¹⁾.