Category Clinical Research
CCC Critical Care compendium 340

Risk and Numbers Needed to Treat

Risk is a nebulous term in evidence-based medicine, as it may refer to either relative or absolute risks. Overall, absolute risks are more meaningful and can be converted in 'numbers need to treat' (NNT), which are useful in the clinical setting

CCC Critical Care compendium 340

Case-Control Studies

Case-Control Studies: a type of retrospective observational study; control patients are ‘matched’ using some criteria (age, gender), typically should have no history of the disease of interest and should be representative of the general population

CCC Critical Care compendium 340

Adaptive Trial Designs

An adaptive clinical trial involves a study design in which key characteristics are adjusted while enrollment in the trial is ongoing using prospectively defined decision rules and in response to information arising from the data accumulating in the trial

CCC Critical Care compendium 340

Chi-square Test

Chi-square Test is used to compare categorical data; often displayed in contingency table with rows (x) and columns (y)

CCC Critical Care compendium 340

Before-and-after studies

Non-experimental observational study design used to assess the effect of an intervention based on comparison of outcomes prior to its use and afterward

CCC Critical Care compendium 340

Subgroup Analysis

Subgroup analysis involves assessing an association between an intervention (or other factor) and a subset of the patients that were exposed. Subgroup analysis can be decided upon a priori or performed post hoc

CCC Critical Care compendium 340

Publication Practices Distort Science

Scientific information is an economic commodity, and that scientific journals are a medium for its dissemination and exchange. As such it is subject to economic factors that affect the value of scientific information and how it is exchanged.

CCC Critical Care compendium 340

Retrospective Studies and Chart Reviews

Retrospective studies are designed to analyse pre-existing data, and are subject to numerous biases as a result. Types of retrospective studies include: case series; retrospective cohort studies; case-control studies