Epidemiology Seminar
Samy Suissa, PhD
Director, Centre for Clinical Epidemiology, Lady Davis Institute
James McGill Professor, Departments of Epidemiology and Biostatistics and of Medicine, McGill University
The number needed to treat: 25 years old and still misunderstood
ALL ARE WELCOME
SYNOPSIS:
The number needed to treat (NNT) is a simple measure of a treatment’s impact, increasingly reported in randomized trials and observational studies, but often incorrectly calculated in studies involving varying follow-up times. We show how these approaches can lead to erroneous values of the NNT and misleading interpretations, illustrating using several published studies, including trials, observational studies and meta-analyses.Ìý We also describe the usefulness of this measure in assessing benefit–risk.
OBJECTIVES:
To understand how to compute and interpret the number needed to treat (NNT)
To recognize the complexity in studies involving varying follow-up times
To learn how to use the NNT in assessing benefit–risk.
BIO:
Professor Suissa, who heads the Canadian Network for Observational Drug Effect Studies (CNODES), has received the Distinguished Investigator award from the Canadian Institute of Health Research (CIHR) of Canada and the prestigious FC Donders Professorship Award from Universiteit Utrecht, Netherlands.Ìý He has conducted several epidemiological studies on the risks and benefits of medications for the treatment of many chronic diseases.Ìý He has lectured extensively worldwide and authored over 400 peer-reviewed research papers published in scientific journals.Ìý He served on the Board of Directors of several scientific societies and on the editorial boards of various scientific journals including Pharmacoepidemiology and Drug Safety, the European Respiratory Journal, Lancet Respiratory Medicine, COPD -The Journal of Chronic Obstructive Pulmonary Disease, and is a Section Head editor for F-1000 Medicine.
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