Supplementary Data: Risk and benefit information presented to participants
Within 3 hours
You have had a stroke which we think is due to a clot in a blood vessel to the brain.
If you agree, it will be possible to give you thrombolysis, that is treatment with a
clot-dissolving drug. Because we will be able to treat you within 3 hours of your
stroke, we can say that:
Within 3 months of the stroke:

Without thrombolysis, 350 out of every 1000 (35%) patients like you will have
made an excellent recovery, with essentially no major problems due to the
stroke, and 120 out of every 1000 (12%) will be dead..

With thrombolysis, 500 out of every 1000 (50%) patients like you will have
made an excellent recovery, with essentially no major problems due to the
stroke, by 3 months - an increase (improvement) of 150 out of every 1000
patients or 15% compared with those who didn’t get thrombolysis. The risk
of being dead within 3 months of the stroke is 120 out of every 1000 (12%)
patients which is exactly the same compared with those who didn’t get
thrombolysis.

Another way of looking at this is that one out of every 7 people treated with
thrombolysis will have an excellent outcome that they wouldn’t have had
otherwise.
Within 1 week of the stroke:

Without thrombolysis, 10 out of every 1000 (1%) patients like you will have a
symptomatic brain bleed. Half of these brain bleeds will be fatal.

With thrombolysis, 70 out of every 1000 (7%) patients like you will have a
symptomatic brain bleed – that is, symptomatic brain bleed is seven times
more likely. Again, half of these brain bleeds will be fatal.

Another way of looking at this is that one of every 17 people treated with
thrombolysis will have a symptomatic brain bleed they wouldn’t otherwise
have had and one of every 37 people treated with thrombolysis will have a
fatal symptomatic brain bleed they wouldn’t otherwise have had.

Despite this early risk from brain bleed it is important to note that the overall
death rate is not increased in those who receive thrombolysis.
This diagram is another way of showing the benefits and risks of thrombolysis. For
every 100 patients like you, the green men at the top indicate the number that will
do better and the red men the number that will do worse as a result of thrombolysis.
The decision whether or not to have thrombolysis is yours. However, our advice,
and that of professional guidelines and all experts in this area, would be to strongly
recommend that you accept treatment with thrombolysis.
Between 3 and 4.5 hours
You have had a stroke which we think is due to a clot in a blood vessel to the brain.
If you agree, it will be possible to give you thrombolysis, that is, treatment with a
clot-dissolving drug. Because we will be able to treat you within 4 and a half hours
of your stroke, we can say that:
Within 3 months of the stroke:

Without thrombolysis, 350 out of every 1000 (35%) patients like you will have
made an excellent recovery, with essentially no major problems due to the
stroke, and 120 out of every 1000 (12%) patients like you will be dead.

With thrombolysis, 419 out of every 1000 (41.9%) patients will have made an
excellent recovery, with essentially no major problems due to the stroke, and
143 out of every 1000 (14.3%) patients like you will be dead.

In other words, for every 1000 patients like you who receive thrombolysis, an
extra 69 or 6.9% will have an excellent recovery within 3 months of the
stroke and an extra 23 or 2.3% will be dead. While we are very confident
that there is a genuinely increased chance of an excellent recovery with
thrombolysis, we are not so confident that there is a genuinely increased risk
of death with thrombolysis.

Another way of looking at these figures is that one out of every 14 people
treated with thrombolysis will have an excellent outcome that they wouldn’t
have had otherwise but one out of every 43 people treated with
thrombolysis will die as a result.
Within 1 week of the stroke:

Without thrombolysis, 10 out of every 1000 (1%) patients like you will have a
symptomatic brain bleed. Half of these brain bleeds will be fatal.

With thrombolysis, 70 out of every 1000 (7%) patients like you will have a
symptomatic brain bleed – that is, symptomatic brain bleed is seven times
more likely. Again, half of these brain bleeds will be fatal.

Another way of looking at this is that one of every 17 people treated with
thrombolysis will have a symptomatic brain bleed they wouldn’t otherwise
have had and one of every 37 people treated with thrombolysis will have a
fatal symptomatic brain bleed they wouldn’t otherwise have had.

This early risk of a brain bleed is one of the reasons why there may be an
increase in the risk of death following thrombolysis.
This diagram is another way of showing the benefits and risks of thrombolysis. For
every 100 patients like you, the green men at the top indicate the number that will
do better and the red men the number that will do worse as a result of thrombolysis.
The decision whether or not to have thrombolysis is yours. Most professional
guidelines and experts in this area recommend treatment with thrombolysis in this
situation and that is our recommendation also.