Case-Control Studies: The Silver Standard

Abstract

T HE FOCUS of this seminar, the clinical trial, is considered the gold standard of clinical research. J To mount a clinical trial at least 4 elements are necessary. (l) Foremost, a good idea. (We avoid the word, novel in this discussion.) Without an original idea, a clinical trial rarely is a possibility. (2) An enormous, concerted effort and a huge block of time on the part of the principal investigator (PI). The time invested increases exponentially as the work goes forward. (3) Infrastructure. This means qualified and committed coinvestigators, solid statistical support, research nurses/ assistants, data entry persons. A practicing pediatric surgeon working alone, cannot create such a system; it would take a lifetime. The system already must be in place at his or her institution. (4) Funding. Clinical trials are expensive. Without a substantial grant, many good ideas wither on the vine, and many dedicated investigators lose heart. The competition for major grants is formidable. Acquiring one is like winning an Olympic medal. Pediatric surgeons often choose not to compete in this arena, because most are primarily clinicians rather than research investigators. There is another option, however, that is within our reach and can enable us to ask and answer clinical questions: the case-control study. This method is both underused and underrated. Because it is retrospective, the case-control study may be discounted by investigators striving for the gold standard or nothing. Yet historically, case-control studies have provided evidence that helped to answer crucial medical questions, eg, the link between cigarette smoking and lung cancer, the relationship of Reye syndrome to the use of aspirin in children, the link between vaginal c ancer in young women and a maternal exposure to DES (diethylstilbestrol). The casecontrol technique is used commonly to assess the risk of cancer from environmental and industrial exposures, to evaluate drug effects, and discover factors that cause or prevent disease in humans. Well-done case-control studies provide a s ound alternative to clinical trials and could be considered the silver standard.