Time to hospital admission for acute stroke: an observational study

Stroke affects an estimated 40 000 Australians annually,1 with an associated cost of A$1.3–$1.7 billion per year.2,3 Thrombolytic therapy has been shown to improve neurological outcome of acute ischaemic stroke if given within three hours of symptom onset.4

This new emphasis on acute management of stroke has widespread implications. As thrombolysis has many contraindications and exclusion criteria (eg, haemorrhagic stroke, coma and severe deficit),4 the diagnosis of ischaemic stroke must be confirmed, and clinical evaluation and investigations completed within the three-hour "window" after symptom onset. Assuming the time required for investigations, hospital admission and obtaining consent can be reduced to about an hour, patients must arrive at hospital within two hours of symptom onset if they are to be eligible for thrombolysis. Both health professionals and the general public need to be more aware of stroke as a medical emergency to facilitate this early arrival.

Indeed, previous studies have shown that the single most important factor in determining eligibility for thrombolysis is time to admission.5 Although factors associated with this time have been studied overseas, there are no comparable findings for Australia. Given the large distances between centres where thrombolytic therapy might be given in this country, it may not be appropriate to extrapolate findings from more densely populated parts of the world.

We therefore undertook a prospective study of time to admission for patients with suspected acute stroke at the Royal Adelaide Hospital (SA), and the factors associated with this time, as well as final diagnoses and proportion of patients eligible for thrombolysis.

During the study period, 284 patients were admitted with a suspected diagnosis of acute stroke. Final diagnoses and stroke subtypes are summarised in Box 1. Stroke was confirmed in 245 patients (86%), while 39 patients (14%) had other diagnoses, including eight with transient ischaemic attacks. Most strokes were ischaemic (203; 83%).

Mean age of the 245 patients with confirmed stroke was 72 years (range, 20–100 years), and 138 (56%) were male. Twenty-five patients (10%) were unconscious on admission, and the median modified Barthel Index was 51 (range, 0–100).

In this study of 284 patients admitted to hospital with suspected stroke, 35% were admitted within three hours of symptom onset, and 28% within two hours. These values fall within the range found in North America, where 27%–50% of stroke patients were admitted within three hours of symptom onset.5,8,9

After assessment and investigation, 14% of patients in our study were diagnosed with conditions other than stroke — a figure comparable with previous studies.10 In typical cases of stroke, there may be little diagnostic uncertainty. However, expert assessment and imaging is still necessary to confirm the diagnosis and, most importantly, to exclude intra-cerebral haemorrhage and define the stages of ischaemic stroke if thrombolysis is to be considered. Accordingly, management of acute thrombolytic stroke should be restricted to specialist units where appropriate assessment, including imaging and monitoring, is readily available.

We also found that, after investigation, the number of patients eligible for consideration of thrombolytic therapy4 fell to 37 among those presenting within 3 hours of symptom onset (13% of all patients) and 29 among those presenting within 2 hours (9% of all patients). These figures may still be overestimates, as they do not take into account other standard exclusion criteria for thrombolysis, including previous use of anticoagulation therapy, recent surgery, haematological disorders, severe hypertension and seizures.4 Furthermore, we took time of onset as time of waking for those who developed symptoms while asleep. Changing this criterion to time of falling sleep, as in other studies, might further reduce the numbers who could be considered for thrombolysis.

Almost three-quarters of our patients (72%) did not present urgently (within two hours of symptom onset) to the hospital. Delayed admission can be explained in part by remoteness from hospital, but only in a minority of patients. Factors shown to be associated with delayed admission in other studies include uncertain time of symptom onset,8,9 contact with a primary care physician, transportation by means other than an ambulance, and patient failure to perceive danger.8,9,11,12 Loss of consciousness and seizures at onset are associated with shorter admission time.8 Knowledge of the nature and significance of warning symptoms and signs of acute stroke is poor in the urban Australian population,13 and failure to recognise the significance of stroke symptoms was a significant cause of delay in presenting to hospital in a recent study in New South Wales.14

These findings demonstrate a need for public education to optimise the use of new interventional therapies in stroke. Further study is needed in Australia to determine the origin of referral to hospital, mode of transport and priority of triage on arrival at hospital.

We conclude that the successful implementation of thrombolysis for acute stroke will require changes in the organisation of emergency services and hospital departments, as well as in attitudes of the general public toward stroke. The implications for resource allocation and the provision of 24-hour acute neurological assessment and interventional services also need to be evaluated.

4: Effect of location at stroke onset on time to hospital admission