Carbapenem-resistant Enterobacteriaceae (CRE) are an emerging and troublesome group of pathogens. Risk factor studies, outcome studies, and randomized trials are three types of studies conducted to answer different types of questions regarding CRE. These studies pose different types of challenges. We discuss issues in the design and analyses of case-control studies, cohort studies, and randomized trials aimed to address various research questions regarding CRE.
Keywords: carbapenem-resistant Enterobacteriaceae; case-control study; cohort study; competing risk; confounding variable; control group; external control; lead-time bias; randomized trial.