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Specific guide to this web site for:

 1.  Medical School
      in Statistics

 2.  Medical Students

 3.  Science media writers

 4.  High School & College
     Statistic Teachers


1. Harvard led MI study

2. JACC study 

   (J. of Amer. Coll.

3. NEJM cath study

4. Amer. J. of Cardio.
    review of literature


Oat bran study

Pregnancy & Alcohol

Are Geminis really
9. Columbia 'Miracle' Study  

Additional Topics:


Limitations of Meta-Analyses

Large Randomized Clinical Trials

Tale of Two Large

Advocate meta-analyses

Network meta-analyses




A trial led by Harvard Medical School faculty with a trial protocol that was so unintentionally biased that the trial was inherently invalid.

See the multiple favorable replies received including from:

William O'Neill, M.D.,    
Eric Topol, M.D.,       
Jeremy Swan, M.D., 
Peter Sleight, D.M.

(Letters are regarding this particular topic only, and not  generalized comments regarding this website.)

The Story

1. The flawed trial treatment protocol that defined how the trial was to be conducted was available prior to any patients had been entered into the trial. details

2. A  letter was written to the trial investigators detailing the multiple flaws in the trial protocol prior to the study being started and requesting the trial protocol be modified.

3. After receiving a letter essentially stating the trial investigators “know best", a  detailed critique of the trial's failings was published in the Journal of Invasive Cardiology in 1992 prior to the flawed study being completed and published.   The trial investigators, after the study was started, changed the trial protocol to a single higher dose of enteric coated aspirin which is also inadequate. 

4. A copy of the published analysis critiquing the trial was sent with the cover letter to multiple leaders in the field of cardiology.

5. Ultimately, the trial was published with widespread awareness in the cardiology community that there were serious flaws in the trial protocol that limited the applicability of the study.



A major trial designed to study the effects of balloon dilation on patients threatening a heart attack was severely flawed in regards to plans to give an inadequate dose of aspirin1. 

Background:   Aspirin is routinely given to all patients prior to balloon dilatation (angioplasty) of the arteries of the heart. Without aspirin, there is over a 300% increase in the risk of the angioplasty procedure resulting in a heart attack2,3. A study designed4,5 to evaluate angioplasty versus medical treatment gave an insufficient single dose of aspirin to the angioplasty group which inappropriately increases the risk of heart attack occurring with angioplasty.  Hence, by trial design, the study was unintentionally biased against one of the two treatment strategies it was designed to evaluate.

A Flawed Medical Trial: An inappropriately low dose of aspirin potentially resulting in an excess of heart attacks with angioplasty (balloon dilation).
By trial design, the study was seriously biased against one of the two treatment strategies the study was designed to evaluate.     details

Lesson: Medical studies often compare one particular treatment strategy to another particular treatment strategy. A flaw can occur in the study protocol which makes the trial so biased that the results are not readily applicable to the clinical practice of medicine.

1. Roehm E.  A Critique of Selected Aspects of the Thrombolysis in Myocardial Infarction IIB (TIMI IIB) and the Thrombolysis in Myocardial Infarction IIIB (TIMI IIIB) Trials. J Invas Cardio 1992:4:145-154

2. Barnathan E, Schwartz J, et al. Aspirin and dipyridamole in the prevention of acute coronary thrombosis complicating coronary angioplasty. Circulation 1987;76:125-134

3. Schwarz L, Bourassa M, et al. Aspirin and dipyridamole in the prevention of restenosis after percutaneous transluminal coronary angioplasty.
N Engl J Med 1988;318:1714-1719

4. TIMI IIIB protocol. Dec 7,1989.  

5. TIMI IIIB Investigators.  Effects of Tissue Plasminogen Activator and a Comparison of Early Invasive and Conservative Strategies in Unstable Angina and and Non-Q-Wave Myocardial Infarction, Results of the TIMI IIIB Trial, Circulation 1994;89:1545-1556.



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