I have written several times before on the SMART trial and the meta-analysis (MA) written by the Salpeter family team in the Annals of Internal Medicine and suggest that the former might serve as a teaching tool on how not to do a clinical trial and believe the latter could be instructive to those who wish to publish a flawed and opinion laden meta-analysis.
Letters to the editor of the Annals and now a more formal rejoinder has been published-all very critical of the MA and defending the use of a long acting beta agonists (LABA) in conjuction with a inhaled corticosteroid (ICS) in asthma. This article and a 2005 Cochrane review
both provide good data and analysis that lead to the conclusion that LABAs when used in conjunction with ICS in asthma leads to better control, fewer exacerbations and not only does not pose the risk claimed by Salpter but represents the standard of care for patients with more severe asthma.
Mark Twain or Bismark or someone supposedly said that there are two things you should never watch being made- a law and sausage and it has been suggested that MAs should be added to the list.Yet accepting the results of a MA without knowing how it was really made is an act of faith which supposedly we decry in the "age" of evidence based medicine.When your MA turns on the results of one large trial and that trial is seriously flawed the MA is worthless and potentially harmful which is what happened with the SMART trial and the Salpeter Meta-analysis.
Hopefully,the recent Annals article will clear the air. The above cited reference regarding sausages also makes the important point that MA s should include- along with experts in the methodology used- subject matter experts. Some MAs that I see seem to be written by authors who are excited about their meta-analytic skills and seem to believe they can analyze the forests so well that they need not bother to ask a tree expert for input.