Time and predictors of time to treatment for aneurysmal subarachnoid haemorrhage (aSAH): a systematic review

Background: Aneurysmal subarachnoid haemorrhage (aSAH) is a serious form of stroke, for which rapid access to specialist neurocritical care is associated with better outcomes. Delays in the treatment of aSAH appear to be common and may contribute to poor outcomes. We have a limited understanding of the extent and causes of these delays, which hinders the development of interventions to reduce delays and improve outcomes. The aim of this systematic review was to quantify and identify factors associated with time to treatment in aSAH.

Methods: This systematic review was performed according to the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines and was registered in PROSPERO (Reg. No. CRD42019132748). We searched four electronic databases (MEDLINE, EMBASE, Web of Science and Google Scholar) for manuscripts published from January 1998 using pre-designated search terms and search strategy. Main outcomes were duration of delays of time intervals from onset of aSAH to definitive treatment and/or factors related to time to treatment.

Results: A total of 64 studies with 16 different time intervals in the pathway of aSAH patients were identified. Measures of time to treatment varied between studies (e.g. cut-off timepoints or absolute mean/median duration). Factors associated with time to treatment fell into two categories-individual (n = 9 factors, e.g. age, sex and clinical characteristics) and health system (n = 8 factors, e.g. pre-hospital delay or presentation out-of-hours). Demographic factors were not associated with time to treatment. More severe aSAH reduced treatment delay in most studies. Pre-hospital delays (patients delay, late referral, late arrival of ambulance, being transferred between hospitals or arriving at the hospital outside of office hours) were associated with treatment delay. In-hospital factors (patients with complications, procedure before definitive treatment, slow work-up and type of treatment) were less associated with treatment delay.

Conclusions: The pathway from onset to definitive treatment of patients with aSAH consists of multiple stages with multiple influencing factors. This review provides the first comprehensive understanding of extent and factors associated with time to treatment of aSAH. There is an opportunity to target modifiable factors to reduce time to treatment, but further research considering more factors are needed.