In reading the relevant PDSA web page, there doesn't appear to be any studies. Rather, Fosamax is on the list of drugs that patients report as causing 'drug induced thrombocytopenia' aka DITP.
I think it is more like this. If a researcher has a theory on some mechanism about why Fosamax causes patients to report low platelets, then he would write a paper/study explaining his theory and supply evidence to substantiate and convince others of his theory. It is up to the reader to accept or reject the theory. A DITP drug is a fact. A study presents a theory about facts.
FYI, the order of names on a paper is important. The primary author is listed first. The person that contributed least, is listed last. Those that aren't first may not agree with all the assertions presented in a paper.