PROMISING METHODOLOGY, DISAPPOINTING PERFORMANCE
Utrecht, The Netherlands – Instrumental variables appear inappropriate to study the effects of influenza vaccination.
Studies on the effects of influenza vaccination are observational, which means that one should always be aware that an observed association might be distorted due the effects of another factor. This problem, called “confounding”, can be addressed using a promising methodology called “instrumental variables”.
In a recent study, “Instrumental variables in influenza vaccination studies: mission impossible?!” published in Value in Health, the usefulness of this method was evaluated by applying it in a large cohort study of the effects of influenza vaccination. Several potential instruments were studied, but none seemed adequate to control the confounding.
“Though theoretically the instrumental variable approach is a very powerful method to deal with confounding bias in observational studies, in this case study on influenza vaccination we were unable to uncover such an instrument”, says Dr. Rolf Groenwold. The study was co-authored by Eelko Hak, Olaf Klungel, and Arno Hoes.
The will be discussed in a future issue of Value in Health, the official journal of the International Society for Pharmacoeconomics and outcomes Research.
Value in Health (ISSN 1098-3015) publishes papers, concepts, and ideas that advance the field of pharmacoeconomics and outcomes research and help health care leaders to make decisions that are solidly evidence-based. The journal is published bi-monthly and has a regular readership of over 4,000 clinicians, decision-makers, and researchers worldwide.
ISPOR is a nonprofit, international organization that strives to translate pharmacoeconomics and outcomes research into practice to ensure that society allocates scarce health care resources wisely, fairly, and efficiently.
For more information: www.ispor.org
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