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While RR is between 0 and 1, RRR can be negative, indicating adverse effect of treatment. Of course, if there is a null effect, RRR may fluctuate to either side of 0 without there actually being a real adverse effect of treatment. David L. Doggett, Ph.D. Senior Medical Research Analyst Technology Assessment Group ECRI, a non-profit health services research organization 5200 Butler Pike Plymouth Meeting, PA 19462-1298, USA Phone: +1 (610) 825-6000 ext.5509 Fax: +1(610) 834-1275 E-mail: [log in to unmask] > -----Original Message----- > From: Jeanne Lenzer [SMTP:[log in to unmask]] > Sent: Tuesday, August 22, 2000 3:47 AM > To: EBM (E-mail) > Subject: When treatment harms > > 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 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%