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Although I admittedly do not have access to the full journal article, the complaint in the Journal Watch response seems to relate more to the individual study (which has some fundamental issues) rather than RCTs as a whole. Keep in mind the original study for DIGAMI 1 was published in 1995, while the original CONSORT statement wasn’t released until 1996 so the initial researchers did not have access to the same reporting standards we have today which could have a serious effect on experimental design.
From looking at the abstract of the article, the chief issue
seems to be that the control group is vaguely defined as “conventional
glucose-lower treatment” which is so ill-defined that it could represent a
number of different interventions. It
appears from the complaint that there was a lack of standardization within and
perhaps substandard monitoring of the control group which suggests the study
evaluates the effectiveness of intensive insulin care versus a number of other
potential treatment options (some of which may be more or less effective than the
others). This is a valid complaint, but
it doesn’t relate to the applicability of RCTs in general, just less
methodologically robust evaluations.
I’m admittedly still a little confused about the final
comment “This suggests the contrast [between groups] is not because insulin was
better, but that 'control' was worse.” My
interpretation is that the author is complaining about the lack of control
exercised over the non-treatment group which led to a less than perfect comparison, but I
may be way off base here.
In the end, I believe the lesson from this study and the reception is that time
does not heal all wounds, and a potential lack of methodological rigor in the
initial study should be included in your interpretation of the results of the
20 year follow-up.
Hi,
I wanted to ask if there was any discussion about the EBM implications surrounding a longterm follow-up study RCT in intensive diabetes management status post myocardial infarction, published in a Lancet sub-journal:
"Intensified insulin-based glycaemic control after myocardial infarction: mortality during 20 year follow-up of the randomised Diabetes Mellitus Insulin Glucose Infusion in Acute Myocardial Infarction (DIGAMI 1) trial" (http://www.thelancet.com/journals/landia/article/PIIS2213-8587(14)70088-9/abstract)
Given the large deference paid to RCTs by the medical community at large, the serious validity concerns that commentators raise capture my attention. For example, in an abstract published by NEJM Journal watch the author reports the following:
One expert notes that the patients were less likely to receive now-proven therapies like ACE inhibitors and statins (statins weren't even available at the study's start). And another expert speculates that many more control patients may have been treated with sulfonylureas, which may have adverse cardiovascular effects. "This suggests the contrast [between groups] is not because insulin was better, but that 'control' was worse," he says.
Appealing to the expertise 'in the room," does this criticism about a confounded control group illustrate well understood vulnerabilities of RCTs or are there novel lessons to be learned from trial design?
Thanks all,
Patrick Burke
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