Creating Composite Indices From Continuous Variables for Research: The Geometric Mean

Clinical research focuses on the relationship between one or more independent variables and some dependent variable outcome chosen to reflect underlying process. For categorical variables, may either be focused a specific end point such as myocardial infarction (MI) an construct vascular disease (with MI just exemplar). In latter instance, composite index major adverse cardiovascular event (MACE), defined nonfatal stroke, MI, death, used. Composite outcomes MACE optimize power by ensuring high rate, results they yield are generalizable diseases that consistent with construct. It is therefore surprising there no widely used method combine continuous into outcomes. Nevertheless, clear need for methodology when cannot easily captured measurement. Glucose control example of can assessed in many ways, including fasting postprandial plasma glucose, HbA1c, fructosamine, “time target.” A two these could provide better reflection glucose than any alone. Whereas sophisticated statistical techniques structural equation modeling (1) model latent from measurements, simpler way combining them reflects powerful tool both researchers clinicians. Such approach described below. When same measurements made using …