To our knowledge, this is the first study that describes long-term disability and quality of life of SAH patients admitted to ICU as primary outcome.
As highlighted by several papers, patient-centred outcomes are key elements in clinical studies23,24.
Regarding disability, the study of Chalard K. et al. is the only one that evaluates long-term disability in a cohort of SAH patients admitted to ICU. This study showed a higher incidence of poor outcome compared to our cohort6.
There are some reasons that could explain these findings: first of all, we used a different scale to evaluate disability compared to the study reported above. We used GOSE rather than mRS because in our centre is the most used scale to evaluate long-term outcome in patients with acute brain injury and, with GOS, it has been widely used in literature in SAH patients9.
Secondly, we excluded patients with catastrophic brain injury in which treatment was considered futile since admission.
Finally, our higher incidence of good outcome could be related to a low cut-point on GOSE. There is no consensus on the cut-off point to define favourable outcome with GOSE in acute brain injury patients. As shown in a recent paper by Zuckerman et al25 there is a wide range of cut-points on GOSE in patients with acute brain injury that ranges from 326 to 727. Accordingly with other Authors20,28, we included GOSE 4 among favourable outcome, recognizing functional independence for at least 8 hours as a favourable outcome for patients and caregivers
Our results seem to support our choice; as shown in Table 3, EQ-5D Index and EQ-VAS in group GOSE 4 are more similar to higher grades (GOSE 6-8) than to the lower ones.
Another major issue of discussion regarding outcome is the quality of life perceived by the patients. Median EQ-VAS varies significantly among GOSE grades (p=0.019), while median EQ-index is not significantly different. This could be related to a small sample-size, but also to a broader effectiveness of EQ-VAS in summarizing overall health that is closer to the patient’s perspective. As reported in Table 3, the highest GOSE grades are not the ones with the highest values of EQ-5D Index and EQ-VAS. This is a phenomenon known as disability paradox29. Several studies have shown that many patients, despite a severe disability after brain injury, enjoy a high quality of life30. It is remarkable the broad range of EQ-VAS and EQ-5D Index in the GOSE 3 group in our cohort: in fact, in this group usually considered as unfavourable outcome in studies on acute brain injury, there are a patient with poor quality of life (EQ-5D Index -0.594 and EQ-VAS of 20) and a patient with good quality of life (EQ-5D Index 0.883, EQ-VAS of 80). Should this still be considered a poor outcome or should we focus our attention on the perceived quality of life? It is a thought question that goes behind the purpose of this study, but that should foster a debate.
This poses, if possible, even major challenges to physicians when talking about prognostication in patients with poor-grade SAH and highlights the importance of shared-decision making with the patients and/or the family in this field31; moreover, this remarks the importance of patient-centred outcome studies.
Unfortunately, few are the tools available during ICU stay to evaluate prognosis in this group of patients.
Regarding baseline data, in our cohort females seem to have a better prognosis compared to males; to our knowledge, in previous reports are reported no sex differences in long-term outcome of SAH patients32. This could be related to a small sample size and it will require further studies to understand this finding.
In this study, of the most used severity scale, only HH scale seems to show a relation with poor outcome. This scale, introduced in 1968, was first used to predict the rate of mortality based solely on the clinical features in SAH patients; higher HH grades have been associated with poor outcomes also in more recent studies33,34. However, since HH scale does not take in account the presence of reversible causes of coma such as hydrocephalus and seizures, we agree that this scale should not be used alone to define the prognosis of SAH patients.
Consistently with other studies6,35, GCS at admission is related to long-term outcome in our cohort. The level of consciousness in patients admitted with SAH could represent the epiphenomenon of the early brain injury that is developing after aneurismal rupture; the pathophysiology of this process it is not completely understood and should be the object of further studies. Nonetheless, a poor GCS at admission could be associated with a good recovery as shown by Hoogmeoed et al36.
Among SAH-related complications, only high early intracranial hypertension was related with poor outcome in our cohort. This finding could have different explanations. Early HICP could be related to a well-known cause such as hydrocephalus, but this was not related to poor outcome in our cohort. Possibly, early HICP could be a surrogate marker of EBI due to loss of autoregulation37 or cerebral edema14,38.
As highlighted in other papers, our data support the lack of relation between vasospasm detected on TCD and/or CTA and long-term outcome. The incidence of vasospasm is similar to other cohorts of patients6 and emphasises the importance of distinguishing between vasospasm, DCI and DCIn4. As highlighted by recent papers, DCI has a complex pathology in which vasospasm is just one of the determinants of brain injury. TCD and angiographic spasm seem to pose the patients at higher risk of DCI, but this is not related to long-term outcome39–41.
Instead, DCI can lead to DCIn, a well-known factor related to long-term poor outcome.
DCI can be suspected in patients with clinical deterioration or in patients with impaired CT-perfusion17. As remarked by the same authors that proposed the definition of clinical deterioration due to DCI in 2010, diagnosis of DCI can be tricky due to several confounders, especially in ICU patients18. The presence of several confounders combined with the small sample size could explain the lack of relation between DCI and long-term outcome in our cohort. Another possible explanation is that DCI is not strictly related to DCIn. In fact, in our cohort, only 25% of patients who had impaired CT-perfusion developed DCIn. This seems to support the hypothesis that DCI detected on CT-perfusion still represents a reversible situation that requires the highest quality of care to prevent DCIn42,43.
Limitations
The main limitation of the study is the small sample size. A larger number of cases would allow multivariate analysis to identify independent outcomes predictors.
mRS seems to be a better outcome measure for SAH patients, but GOSE is still widely used. Moreover, in our Institution GOSE is widely used as an outcome scale for patients with acute brain injury and physicians and nurses are well-trained in its use.
Regarding dichotomizations, there are several cut-offs reported in the literature that could limit the comparison between studies.
Another limitation is the use of caregivers as surrogate to evaluate QoL, but this is recommended in all the cases in which the patients it is unable to answer. This study does not include patients admitted in good neurological condition and managed in the neurosurgery ward throughout their hospital stay.