Your Easy Guide to Clinical Studies

Study outcomes/endpoints are variables that are medical values or information of interest to a researcher to address the research question.

 

As any variable, study outcome/endpoint variables, can be of different types, such as:    

 

• Continuous variables (e.g. weight, lab values such as cholesterol-, blood pressure values)

 

• Categorical variables (e.g. such as the categorisation into bad/normal/good)

 

• Binary variables (e.g. expressed as binary categories such as, dead/alive, yes/no, normal/abnormal, accepted/rejected)

 

• Count variables (e.g. number of hospital visits)

 

• Time-to-event variables (e.g. time to initial cardiovascular event)

As a SP-INV, make yourself familiar with how to define your study outcome/endpoint variables. Aspects to include are:

 

• A precise definition of the outcomes type. For example, if you are interested in re-hospitalization: do you want to draw conclusions about the occurrence (yes or no), the number as a count or as categories (e.g., 0, 1 to 3, more than 3), the time relapsed until the first re-hospitalization?

 

• The definition of the time point of interest: are you interested in any re-hospitalization occurring in the first 3 months after surgery, or the “number of re-hospitalizations” during a 2 year follow-up?

References

ICH Topic E9 statistical Principles for Clinical Trials – see in particular

• 2.2.2 Primary and secondary variables
• 2.2.5 Multiple Primary Variables