Figures don't know where they come from, but you do.
Trial outcomes, Relative Risks, outcomes of presidency elections,
euthanasia and Your Daughter Again Being Late For Dinner, it all can be
counted, logtransformed, 95 % Confidence Interval included.
But the valuing of the outcome depends on what you consider as good or
bad, formalised in the choice of a gold standard, the concerning cut-off
point and an agreement on the size of the acceptable grey range around
that cut-off point (to make it more complicated: ..and it depends on the
accepted level of uncertainty when applying the results to patient care, this
uncertainty tolerance differs - intuitively - from the concept of 95%C.I.).
So, a treatment is effective
""to prevent death by stroke"" or
""to prevent death all causes within a year"" or
""to change dying from stroke next year into living in a nursing home
for the coming 10 years and then die from falling out of bed""
At least patients differ widely in their choice of the preferred gold standard
outcome.
Similarely, we value the behaviour of our daughter Being Late Again For
Dinner as:
""even once 5 min too late is considered as bad behaviour""
""late for < 15 min / flat bicycle tire / sad boy friend is not bad""
""mean time of being late should be zero""
She never tried the latter though I would be happy if she did, giving me an
excuse to do the same.
Nico van Duijn
Date sent: Tue, 22 Aug 2000 03:47:22 -0400
Subject: When treatment harms
From: Jeanne Lenzer <[log in to unmask]>
To: "EBM (E-mail)" <[log in to unmask]>
Send reply to: Jeanne Lenzer <[log in to unmask]>
> Just an uneducated question, re: a listmember's query:
> (snip) - "I am getting some negative RRR [with CAT snipper]. What
> would be their interpretation?. I know that RRR = 0 is null effect
> and RRR= 1 is cure."
>
> Here's my question: If - as must be presumed by the range for RRR of
> 0-1 - the term RRR assesses only efficacy of intervention and not
> risks of intervention - is there a number that incorporates risk of
> treatment? (In other words a more global assessment of intervention
> that would allow a negative outcome)?
>
> Without such a global value, how do we measure the many thrombolytic
> trials in stroke, for example, that show more deaths with treatment
> intervention than without? I am increasingly concerned by the ways
> sponsored researchers do "spin control" and it seems to me that RRR is
> one such term that can be so abused if the reader is not alert. For
> example, an intervention that reduces a primary endpoint (fatal MI in
> the pt with diabetes) but increases total death rate (from
> pancreatitis/hepatitis whatever - [shades of Rezulin]) the outcome may
> be spun as positive through a set of maneuvers from a.) referring to a
> positive RRR (correctly) and then b.) combining endpoints (death and
> disability) to a more neutral - or even positive effect (as has been
> done in the thrombolytic trials).
>
> Have I misunderstood something here?
>
> jeanne
>
Dr.N.P. van Duijn, General Practitioner
Department of General Practice
Division Public Health
Academic Medical Centre
University of Amsterdam
Meibergdreef 15
1105 AZ Amsterdam
& Primary Health Care Centre 'de Haak'
Almere
the Netherlands
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