Prognostic value of premorbid hypertension and neurological status in aneurysmal subarachnoid hemorrhage: pooled analyses of individual patient data in the SAHIT repository - Jaja, B NR; Lingsma, H; Schweizer, T A; Thorpe, K E; Steyerberg, E W; Macdonald, R L; SAHIT collaboration (J Neurosurg, 2015)