title: Systematic review of clinical prediction tools and prognostic factors in aneurysmal subarachnoid hemorrhage.
abstract: BACKGROUND
  Clinical prediction tools assist in clinical outcome prediction. They quantify the relative contributions of certain variables and condense information that identifies important indicators or predictors to a targeted condition. This systematic review synthesizes and critically appraises the methodologic quality of studies that derive both clinical predictors and clinical predictor tools used to determine outcome prognosis in patients suffering from aneurysmal subarachnoid hemorrhage (SAH).
  
  
  METHODS
  This systematic review included prospective and retrospective cohort studies, and randomized controlled trials (RCTs) investigating prognostic factors and clinical prediction tools associated with determining the neurologic outcome in adult patients with aneurysmal SAH.
  
  
  RESULTS
  Twenty-two studies were included in this systemic review. Independent, confounding, and outcome variables were studied. Methodologic quality of individual studies was also analyzed. Included were 3 studies analyzing databases from RCTs, 8 prospective cohort studies, and 11 retrospective cohort studies. The most frequently retained significant clinical prognostic factors for long-term neurologic outcome prediction include age, neurological grade, blood clot thickness, and aneurysm size.
  
  
  CONCLUSIONS
  Systematic reviews for clinical prognostic factors and clinical prediction tools in aneurysmal SAH face a number of methodological challenges. These include within and between study patient heterogeneity, regional variations in treatment protocols, patient referral biases, and differences in treatment, and prognosis viewpoints across different cultures.
authors: Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada.
authors: Benjamin W Y
authors: BW
authors: Lo
authors: Department of Neurosurgery, Kurashiki Central Hospital, University of Kyoto, Okayama, Japan.
authors: Hitoshi
authors: H
authors: Fukuda
authors: Department of Neurosurgery, Nagoya University Hospital, Nagoya University, Nagoya, Japan.
authors: Yusuke
authors: Y
authors: Nishimura
authors: Department of Surgery, and Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Canada.
authors: Forough
authors: F
authors: Farrokhyar
authors: Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Canada.
authors: Lehana
authors: L
authors: Thabane
authors: Department of Medicine and Clinical Epidemiology and Biostatistics, Division of Clinical Pharmacology, McMaster University, Hamilton, Canada.
authors: Mitchell A H
authors: MA
authors: Levine
keywords: Aneurysmal subarachnoid hemorrhage; aneurysms; clinical outcome prediction; health research methodology; prognosis; systematic review