Assessing Medical Research (3)

Published medical research can be designed in a variety of ways but the greatest credence is given to placebo-controlled randomized trials (PCRT).  Ideally, and in simplest form, this design has the following characteristics:

  • Subjects are chosen from a pool of individuals representative of the population the researcher wishes to study.  An example would be patients coming to a mental health clinic for treatment of depression.
  • Subjects are then randomly selected to receive either the treatment the researcher is studying or another form of treatment for comparison.  If the research treatment is a medication then often it will be compared with a placebo (sugar tablet).
  • In most studies of medication, neither the researcher nor the subject knows which kind of tablet they are taking until after the results have been collected.  When this is done, the study is referred to as “double-blind” referring to the researcher and the subjects.  This avoids bias in recording results.

When you hear about a study designed in this way, the results are likely to be valid, certainly far more than the many claimed results that seem to have no research behind them at all.  However, even with PCRTs, many issues can cloud the picture.  For example, if the study was done at a VA hospital or in another community with unrepresentative demographics, results may not be applicable to the rest of the population.  Next, if the number of subjects was low (dozens), then small but meaningful benefits (or harms) of the research treatment may not show up in the statistics.  The treatment might therefore be classed as unhelpful prematurely.  On the other hand, if the number of subjects was very large (hundreds or thousands), benefits of the treatment shown by the study may be real but slight so pay attention to how big a benefit was found.

This will give you a few ideas to help weed out some of the unsubstantiated health care claims that continually pollute the news media.  You can also arm your natural skepticism with the following line: “When faced with a difficult medical dilemma, the medical student  said “I don’t know the answer”, the celebrity health authority said “I have the answer” and the wise medical professor said “The answer is not known.”

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