Users' guide to the surgical literature. Case-control studies in surgical journals.
BACKGROUND
Some articles in surgical journals identify themselves as case-control studies, but their methods differ substantially from conventional epidemiologic case-control study (ECC) designs. Most of these studies appear instead to be retrospective cohort studies or comparisons of case series.


METHODS
We identified all self-identified "case-control" studies published between 1995 and 2000 in 6 surgical journals, to determine the proportion that were true ECCs and to identify study characteristics associated with being true ECCs.


RESULTS
Only 19 out of 55 articles (35%) described true ECCs. More likely to be ECCs were those articles that reported "odds ratios" (ORs) (the OR for being an ECC if a study reported "ORs" compared with those reporting no "ORs" 15.3; 95% confidence interval [CI] 2.8-82.6) and whose methods included logistic regression analysis (OR 3.6, CI 1.0-12.9). Studies that focused on the evaluation of a surgical procedure were less likely to be ECCs (OR 0.2, CI 0.1-0.7) than other types of studies, such as those focusing on risk factors for disease.


CONCLUSIONS
The term "case-control study" is frequently misused in the surgical literature.
Mihailovic
Alexandra
A
Department of Surgery, Toronto General Hospital Research Institute, Toronto, Ont.
Bell
Chaim M
CM
Urbach
David R
DR
D016022:Case-Control Studies; D015340:Epidemiologic Research Design; D013502:General Surgery; D006801:Humans; D016015:Logistic Models; D016017:Odds Ratio; D010506:Periodicals as Topic / Q000706:statistics & numerical data*; D009626:Terminology as Topic