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GCS as predictor of outcome for subarachnoid haemorrhage

Three Part Question

[In patients with acute subarachnoid haemorrhage] does [GCS] predict [outcome, morbidity or mortality]?

Clinical Scenario

A 27 year old male presents to the emergency department with a severe headache. A subarchnoid haemorrhage is suspected, the diagnosis is confirmed by CT. His GCS on admission is 8, you wonder if this will have any implication on his overall outcome.

Search Strategy

Medline 1966-2006 July week 1 using ovid interface
Embase 1980-2006 week 1using ovid interface
CINAL 1982-2006 July week 2 using ovid interface
[{exp Intracranial Aneurysm/ or exp Subarachnoid Hemorrhage/} OR {(subarachnoid adj (hemorrhage$ or haemorrhage$ or bleed$)).mp.} AND [{exp Glasgow Coma Scale/} OR {(Glasgow adj Coma$ adj Scale$).mp.} OR {}] AND [{exp Prognosis/} OR {(prognosis$ or outcome$).mp.} OR {(morbidity$ or mortality$).mp.}]. Limit search to humans and English.
Embase and Cinahl
[{exp Subarachnoid Hemorrhage/} OR {(subarachnoid adj (hemorrhage$ or haemorrhage$ or bleed$)).mp.} AND [{exp Glasgow Coma Scale/} OR {(Glasgow adj Coma$ adj Scale$).mp.} OR {}] AND [{exp Prognosis/} OR {(prognosis$ or outcome$).mp.} OR {(morbidity$ or mortality$).mp.}]. Limit search to humans and English.
[{Mesh Descriptor Subarachnoid Hemorrhage explode all trees} OR {( subarachnoid* hemorrhage*) OR (subarachnoid* haemorrhage*) OR (SAH)}] AND [{Mesh Descriptor Glasgow Coma Scale explode all trees} OR {(Glasgow* coma* scale*) or (GCS)}]
All searches limited tum humans and English Language

Search Outcome

Medline 294 papers
Embase 253 papers
CINAHL 27 papers
Cochrane 27 papers
From these papers 7 papers were found to be relevant.

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Lagares et al
Patients with SAHRetrospective Cohort study 2bScore on Glasgow Outcome Scale at 6 months. Scores 12 and 2 were classified as a good outcome (G) and 3, 4 and 5 as a poor outcome (P).442 patients, 6 were lost to follow up. GCS 15 (205) G177 P28 p<0.001; GCS 12-14 (132) G71 P61 p=0.09; GCS 9-11 (16) G3 P13 p=0.4; GCS 6-8 (30) G7 P23 p=0.06; GCS <6 (53) G4 P49. The p values are to see if there is a significant dufference between adjacent groups.The majority of the data is not statistically significant. The authors also show bias toward the new scale they have developed.
Ingagawa T
123 patients with SAHRetrospective cohort study. Level 2bGCS as a predictor for mortality at 30 days and 2 yearsGCS 15 30D = 100% p=0.693, 2Y = 97% p=0.175; GCS 13-14 30D =94% p0.664, 2Y = 88% p=0.406; GCS 7-12 30D = 69% p=0.003, 2Y = 65% p=0.230; GCS 3-6 30D 20% p=0.099, 2Y = 17% p=0.343.The numbers involved in the study were small and only mortality was considered as an outcome. The data was shown to be not statistically significant but the author still comes to the conclusion that GCS predicts mortality at 30 days and 2 years.
Takagi K et al
1398 patients with aneurysmal SAHRetrospective cohort study. Level 2b.Glasgow outcome score. A scale from 1-5. 1 is death 5 is good recoveryOverall there is a better outcome with a higher GCS score preoperatively. A GOS of five was as follows: GCS 15 = 84.6% p<0.000001; GCS 14 = 68% p=0.026; GCS 13 = 56.1% p=0.97;GCS 12 = 54.7% p=0.96; GCS 11 = 53.8% p=0.11; GCS10 =37.5 p=0.52; GCS 9 = 37.8% p=0.81; GCS 8 = 41.3% p=0.01; GCS 7 = 26.2% p=0.083; GCS 6 = 14.7% p=0.40; GCS 5 = 21.1% p=0.46; GCS 4 = 12.7% p=0.08; GCS3 = 3.1%. P values are for significance of difference between adjacent scoresThe data between the scores is not statistically valid so does not answer my question. The author suggests where there is statistical significance the scores can be split into groups. Although the sample size is large no sample size estimates have been performed so the lack of significance could be due to insufficient data
Chiang VL at al
56 patients with altered mental status after SAH. All were undergoing surgery.Retrospective cohort study. Level 2b.GOS at 6 months in comparison to worst and best GCS Pre-treatment and post treatment scores.Using GSC all grades are significantly valid for prediction of outcome p<0.05, especially if the worst pre-treatment score is used p = 0.0001Small study group. Data on GCS is not presents in tables and the author shows bias toward other scales measured.
Lin CL at al
56 patients with SAHRetrospective cohort studyThe 46 patients who survived were interviewed over a period ranging 10-18 monthsGCS on discharge was predictive of activity of daily life at follow up. 80% of the patients experienced a good recovery.A small study. The abstract does not state if the data was statistically valid.
Oshiro EM et al
Patients with aneurysmal SAHRetrospective cohort study. Level 2bGOS and MortalityGCS 15 Mortality 4.9%, Mean GOS 4.2; GCS 12-14 Mortality 14.8%, Mean GOS 3.6; GCS 9-11 Mortality 19%, Mean GOS 2.7; GCS 6-8 Mortality 56.2% Mean GOS 1.9; GCS 3-5 Mortality 78.6%, Mean GOS 1.4. GCS was the strongest predictor for discharge odds ratio 2.585 p<0.0001 but not mortality.No reason was given for grouping the GCS scores in such a way. The GOS scores were only given at discharge and perhaps if a follow up had been done the outcome would have been different.
Longstreth WT et al
Patients with aneurysmal SAH 18 years and above.Retrospective cohort study. Level 2b.Glasgow outcome scale (GOS) at 1 month and 1 year after ictus.GCS on admission was best predictor of outcome: GCS 13-15 (19) none had a poor outcome; GCS 8-12 (86) 27% had a poor outcome; GCS 6-7 (15) 67% had a poor outcome; GCS 3-5 (46) 98% had a poor outcome. The odds ratio for this being statistically significant is 0.56.The sample size was small but no explaination was given for this. The stats calculations were difficult to interpret and no p values were calculated


Many of the studies have grouped the GCS grades together. The only paper that doesn't does show that between adjacent GCS scores there is little clinical significance. However, in all the papers found there is an overall trend of a worse outcome with declining GCS Score. Tagaki et al found that 1 patient with a GCS of 3 survived with a good outcome. This shows that there are exceptions to this conclusion so the trend of worsening outcome with declining GSC scores is a general trend not an absolute.

Clinical Bottom Line

GCS score on admission does correlate with outcome but this is a general trend rather than an absolute for each score.


  1. Lagares A et al A Comparison of Different Grading Scales for Predicting Outcome After Subarachnoid Haemorrhage. Acta Neurochirurgica 2005; 5-16
  2. Inagawa T et al Primary Intracerebral and Aneurysmal Subarachnoid Hemorrhage in Izumo City, Japan. Part 2: Management and Surgical Outcome. Journal of Neurosurgery 2000;967-975
  3. Takagi K et al How Should a Subarachnoid Hemorrhage Grading Scale be Determined? A Combinatorial Approach Based Solely on the Glasgow Coma Scale. Journal of Neurosurgery 1999;680-687
  4. Chiang VL et al Toward More Rational Prediction of Outcome in Patients with High-grade Subarachnoid Hemorrhage. Neurosurgery 2000; 28-36
  5. Lin CL et al Outcome of Spontaneous Subarachnoid Hemorrhage of Unknown Etiology. Kaohsiung Journal of Medical Sciences. 1998;625-632
  6. Oshiro EM et al A New Subarachnoid Based on the Glasgow Coma Scale: A Comparison with the Hunt and Hess and World Federation of Neurological Surgeons Scales in a Clinical Series. Neurosurgery 1997;140-148
  7. Longstreth WT et al . Clinical Course of Spontaneous Subarachnoid Hemorrhage: A Population-Based Study in King County, Washington. Neurology 1993:712-718.