The international stroke trial database

Published online Mar 6. Author information Article notes Copyright and License information Disclaimer. Corresponding author. Peter AG Sandercock: ku. Received Mar 5; Accepted Mar 6.

This corrects the article " The International Stroke Trial database " in volume 12 on page CSV 4. Abstract Background We aimed to make individual patient data from the International Stroke Trial IST , one of the largest randomised trials ever conducted in acute stroke, available for public use, to facilitate the planning of future trials and to permit additional secondary analyses. Methods For each randomised patient, we have extracted data on the variables assessed at randomisation, at the early outcome point days after randomisation or prior discharge and at 6-months and provide them as an analysable database.

Conclusions The IST dataset provides a source of primary data which could be used for planning further trials, for sample size calculations and for novel secondary analyses. Results Consent for publication of raw data was not obtained from participants. Table 1 Country codes used in International Stroke Trial. Open in a separate window. Table 2 Variables names and comments. The terminology for the allocated dose of unfractioned heparin changed slightly from the pilot to the main study. Patients were allocated either units subcutaneously twice daily coded as H in the pilot and M in the main trial , units twice daily coded as L throughout or to 'avoid heparin' coded as N throughout.

Should not have been randomised 2. Refused treatment 3. Initial event not a stroke 4. Haemorrhagic stroke 5. Non compliers 6. Discharged after 14 days 7. Discharged up to 14 days 8. Died prior to receiving the study drug s 9.

Died after receiving the study drug s Stated atrial fibrillation Administration problem Missed out more than 3 doses Haemorrhagic stroke. Table 4 Final diagnosis of initial event. Number Ischaemic stroke Haemorrhagic stroke Definite stroke, pathological type unknown Not a stroke Uncertain diagnosis 26 Total Anonymisation As recommended by Hrynaszkiewicz et al.

Discussion This large data set, with very complete follow-up, includes a very broad range of acute stroke patients with a uniquely large number of very elderly patients, and so may be useful to researchers planning future research studies.

Competing interests The trial was designed, conducted, analyzed, and reported independently of all sponsors. Note for users of the data set The authors ask that any publications arising from the use of this dataset acknowledges the source of the dataset, its funding and the collaborative group that collected the data.

Authors' contributions PS was the Chief Investigator of the IST responsible for the overall design, conduct and presentation of the study results. Click here for file 4. Acknowledgements The chief acknowledgement is to the thousands of stroke patients who joined the IST and to their doctors. International Stroke Trial Collaborative Group. The International Stroke Trial IST : A randomised trial of aspirin, subcutaneous heparin, both, or neither among 19 patients with acute ischaemic stroke.

Preparing raw clinical data for publication: guidance for journal editors, authors, and peer reviewers. Improving clinical practice in stroke through audit: results of three rounds of National Stroke Audit. J Eval Clin Pract. The neglected burden of stroke in Sub-Saharan Africa. International Journal of Stroke. Prevention and management of stroke in very elderly patients. Lancet Neurol. Evaluating non-randomised intervention studies. Consent for publication of raw data was not obtained from participants.

Consent for participation in the trial was obtained from all subjects or from an appropriate proxy, according to the procedures approved by relevant national and local hospital ethics committees or Institutional Review Boards [IRB].

These patients were treated years ago, and many have died. Patients and hospitals are identified only by an anonymous code; there are no identifying data such as name, address or social security numbers; patient age has been rounded to the nearest whole number. In our view, publication of the dataset clearly presents no material risk to confidentiality of study participants. The dataset includes the following baseline data: age, gender, time from onset to randomisation, presence or absence of atrial fibrillation AF , aspirin administration within 3 days prior to randomisation, systolic blood pressure at randomisation, level of consciousness and neurological deficit.

We extracted events within 14 days on: the occurrence of recurrent stroke, pulmonary embolism, and death date and cause of death.

At 6 months we extracted: degree of recovery, place of residence and current use of antiplatelet or anticoagulant drugs and death date and cause of death. The cause of death was classified as: due to initial stroke, recurrent ischaemic stroke, recurrent haemorrhagic stroke, pneumonia, coronary artery disease, pulmonary embolism, other vascular cause or a nonvascular cause.

Patients were assigned to one of 6 categories according to the place of residence at 6 months following stroke: own home, relatives home, residential care, nursing home, other hospital departments or unknown.

The variables extracted are listed with a brief description of each in Tables 1 , 2 and 3. Nineteen thousand four hundred and thirty five patients from hospitals in 36 countries were randomised within 48 hours of symptoms onset, of whom had a CT before randomisation, were first scanned after randomisation and were not scanned at all. Five thousand one hundred thirty two Given that patients were first scanned after randomisation, and were not scanned at all, the 'final diagnosis' is somewhat imprecise.

However, since the analysis was by intention to treat, all participants were retained in the analysis, irrespective of the final diagnosis. The numbers of patients with each final diagnosis are given in Table 4. Whilst the 'final diagnosis variable' is of some interest, it may be influenced by events occurring after randomisation, so for any future analyses, the least biased assessment of the patient characteristics is that recorded at baseline, before randomisation.

Please note that, in the original Lancet report on the trial [ 1 ], figures two a and two b reported the effects of allocation to aspirin and to heparin on the primary outcome, subdivided by various baseline characteristics and by the final diagnosis. The numbers of patients with each pathological type of stroke are somewhat different to the numbers above, because they relate to the number of patients with complete 6 month follow-up data, whereas the numbers above relate to all randomised patients.

As recommended by Hrynaszkiewicz et al. We therefore present patient's age rounded to the nearest whole number of years.

Time of admission to hospital a potential identifier was not recorded. Dates of events occurring post randomisation have been converted to the number of days from randomisation.

The time variables that were recorded see below referred to time of randomisation in the trial i. This large data set, with very complete follow-up, includes a very broad range of acute stroke patients with a uniquely large number of very elderly patients, and so may be useful to researchers planning future research studies.

Users of the dataset should be aware that the study was conducted at a time when stroke unit care was not widely available and thrombolytic therapy was used rarely and none of the included patients received it [ 3 ].

Thus, the background stroke care for the included subjects, while not typical of present-day acute stroke care [ 4 ], is perhaps more typical of current stroke care in resource poor settings [ 5 ]. Given that the developing world faces a future epidemic of non-communicable diseases, including stroke [ 5 ], these data may therefore prove particularly valuable for planning future trials in resource-poor settings.

In the developed world, the proportion of the general population who are 'very elderly' is rapidly increasing. Older people have been substantially under-represented in stroke trials to date [ 6 ], so we hope the large number of patients aged over 80 in this data set could also facilitate planning of trials in the 'older old'.

The publication of raw datasets such as the IST's may offer wholly unanticipated benefits to the wider research community. For example, the dataset was licensed to an independent statistical group who used the data to estimate the size and direction of biases introduced when non-randomised comparisons were made and the differences between direct and indirect comparisons.

This empirical work led to two important publications on the topic [ 7 , 8 ]. Such additional benefits, realised long after the original trial was completed, are a further clear indication of the value of opening access to such datasets. The authors ask that any publications arising from the use of this dataset acknowledges the source of the dataset, its funding and the collaborative group that collected the data.

Article Google Scholar. J Eval Clin Pract. International Journal of Stroke.