Table 1.

CRE Study Types.

	Risk Factor Studies	Outcome Studies	Randomized Trials
Goals	• Identify risk factors that will help lead to interventions that will decrease the emergence of the resistant pathogen	• Delineate the public health burden of the resistant bacteria such as morbidity, mortality and costs	• Compare interventions for the treatment or prevention of CRE1213473
	• Identify high-risk patients for randomized trials evaluating interventions for CRE
Most common design	Case-control study	Cohort study	Randomized controlled trial
Role of CRE	Outcome	Exposure	Defines population
Important challenges in most common design	• Control-group selection	• Selection of the non-exposed group (non-CRE)	• Identifying CRE patients
	• Control for confounding variables	• Lead-time bias	• Weighing the benefits and risks of alternative therapies
		• Competing risks