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ICH simulator

The Intracerebral Haemorrhage simulator is a tool to help researchers design clinical trials

Intracerebral haemorrhage trial simulator


The 'ICH trial simulator' originated from the Lothian Audit of the Treatment of Cerebral Haemorrhage (LATCH)

What is the 'ICH trial simulator' based on?

How does the ICH trial simulator perform its calculations?

  • This website is intended to help researchers designing studies of adults with spontaneous (non-traumatic) intracerebral haemorrhage (ICH), particularly randomised controlled trials of treatments.
  • The website provides estimates of the proportion of patients with ICH who might be eligible for a trial, based on your chosen selection criteria.
  • The simulator will help you assess the impact of your eligibility criteria on the generalisability and feasibility of your trial.
  • The Lothian Audit of the Treatment of Cerebral Haemorrhage (LATCH) has ascertained all residents in the Lothian Healthboard region of Scotland (mid-2010 population aged 16 years or over was 695,335) who were aged 16 years or over at the time they were diagnosed with first-ever or recurrent ICH confirmed by brain imaging or pathology since 1 June 2010 onwards.
  • We excluded adults with exclusively extra-axial intracranial haemorrhage or ICH definitely attributable to trauma or hemorrhagic transformation of an ischemic stroke.
  • LATCH was approved by the NHS Lothian Caldicott Guardian. Patients in NHS Lothian are informed about the use of their data for audit, and specific information leaflets about LATCH were distributed to inform patients and their carers about their right to opt out.
  • We have published a paper on the first year of LATCH data that contribute to the simulator (Fonville et al. Stroke 2013;44(10):2729-34.
  • The simulator will tell you the number of years of recruitment (and the number of patients) that its calculations are based on.
  • Please click here for the definitions we have used for the variables included in the ICH trial simulator.
  • We recorded the nature of onset of the ICH symptoms in five categories: awake at onset, last seen well, awoke from sleep (and the time last seen well was unknown), unwitnessed sudden death in the community, or unknown. We recorded dates and times (hh:mm) of ICH symptom onset when they were known for patients who were awake at onset or last seen well. If the part of the day, but not the exact time, was known we imputed a time (morning - 08; afternoon - 12:00; evening - 22:00), although this was not done if only the date of onset was known. We used these times/dates and the time and date of the diagnostic brain CT to calculate the interval from symptom onset to diagnosis. Despite the many sources of information about ICH onset time, in clinical practice it has been impossible for us to determine when roughly one quarter of the patients first developed symptoms.
  • The variables that you select limiting parameters for are used to restrict the cohort to patients meeting these criteria.
  • Patients will not meet a criterion if they fall outside the parameters you impose on a variable, or if the variable's value is unknown (see above regarding time of onset as an example of this).
  • Any variables that you do not select criteria for do not limit the inclusion of patients in any way.
  • The simulator provides the total number of patients who would be eligible for your hypothetical trial, as well as the numbers of these patients who survive 30 days, 90 days and 1 year.
  • The proportion of all patients who would be eligible for a trial whose parameters you define is quantified as a percentage of all patients in the LATCH community-based cohort who would be eligible, with 95% confidence intervals around this proportion. The incidence (per 100,000 adults aged 16 years or over per year) is also provided, to enable you to project numbers of recruits according to the population base for your trial.


Click here for a link to the ICH simulator