In the three prior posts of this series I tried to analyze some of the defects in the randomized clinical rials (RCTs) of homeopathic remedies for childhood diarrhea. The first entry showed that the first two RCTs’ (done in Nicaragua) methods could not produce a meaningful result because of the way the RCTs were set up (methods.) The second entry showed that the results obtained in the first two trials were meaningless clinically even if assumed to have resulted from more legitimate methods. The same applied to the third trial in Nepal, analyzed in the third entry.
This entry will suggest that the authors’ fourth paper (Jacobs J, Jonas WB, Jimenez-Perez M, Crothers D. Homeopathy for childhood diarrhea: combined results and metaanalysis from three randomized, controlled clinical trials. Pediat Inf Dis J, 2005;22:229-234.)- a meta-analysis (MA) of the data from the three RCTs resulted in conclusions equally as meaningless as those of the three trials.
The MA authors – several of the same workers from the three RCTs – begin by agreeing that the data from the RCTs, taken individually, were of borderline significance:
In our previous three studies, we evaluated the use of individualized homeopathic treatment of childhood diarrhea … The results of the two larger studies (n = 81, n = 116) were just at or near level of statistical significance. Because all three studies followed the same basic study design , […] we analyzed the combined data from these three studies to obtain greater statistical power. In addition we conducted a meta-analysis of effect-size difference […] to look for consistency of effects.
MAs and systematic reviews (SRs) are the two consensus methods for summarizing data from multiple individual studies. The inclusion and search methods of RCTs for SRs and MAs are similar, but the objectives of the two are a bit different, as are the forms of the reports. In SRs, the results are summarized in more in narrative form, whereas in MAs the data are treated mathematically and the results are defined in statistical terms. Thus authors of SRs are freer to speculate on the degree of confidence that a method is effective based on what is shown by the numbers of positive and negative RCTs collected. Authors of MAs usually limit their comments to what the mathematical formulation of the summarized data show.