Influenza Vaccination To Elderly: Quantifying The Potential Role Of Unmeasured Confounders Through An Example.

We discuss in this review the role of health status as unmeasured confounder in studies regarding the effectiveness of influenza vaccination on health outcomes in older age group. We are reviewing the literature with major emphasis on article by Groenwold et al that discusses different perspectives of the current debate. It provides valuable insights into evaluating unmeasured confounders, functional health status in particular. It is valuable since it provides opportunity for examining the alternative explanations governing uncontrolled confounding. Using example of this article, we present this review with the objective of identifying and assessing unmeasured confounders. We present stepwise approach to identify and assess uncontrolled confounder in a given study.