Statistical Review – Intention-to-Treat Versus Per-Protocol Analyses
Ever read a paper and feel a bit confused about all the statistical jargon and how to properly interpret the findings? At NEJM Resident 360, we’re trying something new and bringing you Statistical Review which aims to cover some key areas in research methodology and trial design. On this episode, we discuss intention-to-treat and per-protocol analyses, how to interpret studies using these approaches, and how they address bias introduced by study attrition and nonadherence.
Introduction: 0:00 Summary of Curbside Consult episode on preventing asthma exacerbations: 00:54 Introduction to intention to treat versus per protocol analyses: 1:58 Participant behavior in clinical trials and minimizing bias: 2:19 Attrition and non-adherence: 3:01 Definition and effects of attrition: 3:26 Definition and effects of non-adherence: 3:54 Intention-to-treat analysis definition and interpretation: 4:30 Limitations of Intention-to-treat analyses: 6:56 Per-protocol analyses definition and interpretation: 7:32 Dealing with bias in per-protocol analyses: 8:24 Benefits and limitations of per-protocol analyses: 9:25 Limitations of both methods: 9:43 Summary and teaching points: 10:00
The Curbside Consults series complements the foundational information in NEJM R360 Rotation Prep by taking a deep dive into key clinical topics with expert clinicians and educators. These podcasts explore and critique the evidence behind clinical practice and break down statistical concepts for the busy clinical trainee.
Angela Castellanos is a general pediatrician and editorial fellow at the NEJM.
Amanda Fernandes is a 2018-2019 NEJM editorial fellow.