Experimental designs for multicomponent interventions among persons with multifactorial geriatric syndromes.

This paper discusses issues about the design of clinical trials to test multicomponent interventions for multifactorial health conditions, such as geriatric syndromes in which more than one risk factor is related to the outcome. The issues covered include: identification and selection of modifiable risk factors related to the outcome of interest, selection of intervention components to reduce the deleterious effects of the modifiable risk factors, assignment of components of the intervention, blinding, sample size requirements and estimation of component effects. Each of these issues is explored using examples from nine illustrative multicomponent intervention trials. Statistical and clinical concerns regarding the design of multicomponent interventions are addressed. We also propose elements of multicomponent interventions for multifactorial health conditions that should be reported in publications and areas where future research is needed.