Review of Tepel et al, NEJM 2000;343:180-4

Biostatistical Reviewer: FrankHarrell

This paper demonstrates that even in a premier journal, statistical reviews are frequently inadequate. Fortunately, the authors got the right answer to their questions, but had the results been "non significant", the use of inefficient and inappropriate analyses would have been the cause.

Minor Problems

  • Table 1 shows the mean, standard deviation, and percentages of various baseline variables stratified by treatment. Means and SDs are poor descriptive statistics for asymetrically distributed variables. Quartiles are far better. And there is no need to stratify by treatment in a randomized trial. Apparent baseline imbalances would have been misleading and would have been counterbalanced by baseline characteristics omitted from Table 1. Table 1 should have thus included only one column. Much more valuable would have been a table or graphic containing patient responses stratified by levels of baseline variables. Who is having contrast-agent-induced reductions in renal function?
  • The authors use improper nomenclature. On the bottom right of P. 181 the authors use the term "relative risk". It is not clear whether this is actually "odds ratio". Odds ratios are preferred (and should be labeled correctly) as they can apply to high- as well as low-risk patients.
  • In a parallel-group randomized trial design, comparisons of major interest are always between treatment arms. In a few places the authors have slightly overemphasized changes over time within patients. Regression to the mean and natural history forces can make such changes difficult to interpret.

Major Problems

  • creatinine1.png:
    creatinine1.png

  • creatinine2.png:
    creatinine2.png

  • creatinineOptimum.png:
    creatinineOptimum.png
Topic attachments
I Attachment Action Size Date Who Comment
creatinine.ss creatinine.s manage 1.5 K 06 Nov 2004 - 08:26 FrankHarrell S code used to analyze SUPPORT data and graph data
creatinine1.pngpng creatinine1.png manage 4.4 K 06 Nov 2004 - 08:24 FrankHarrell  
creatinine2.pngpng creatinine2.png manage 5.2 K 06 Nov 2004 - 08:24 FrankHarrell  
creatinineOptimum.pngpng creatinineOptimum.png manage 4.6 K 06 Nov 2004 - 08:25 FrankHarrell  
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Topic revision: r1 - 06 Nov 2004, FrankHarrell
 

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