To the Editor: We thank Dr. Montgomery for highlighting the important work of his group. As he is well aware, compiling and abstracting clinical trials requires numerous assumptions about study outcome. Likewise, the analyses of association between funding source and outcome require further assumptions, most notably that competing interests are reported consistently. Other issues are more subtle: Should any author with a competing interest or only the first author be considered? Does any kind of support, such as free medication, confer the same risk? Published studies vary somewhat in their application of these definitions.
Nonetheless, what is clear from the body of evidence is that the relationship between funding source, competing interests, and reported outcome is one that we need to understand better. Having shown that associations exist, the task now is to clarify why that might be and what, if anything, might be done about it.