Layman’s abstract for PST paper: A new approach to account for intercurrent events

Each week, we will be publishing layman’s abstracts of new articles from our prestigious portfolio of journals in statistics. The aim is to highlight the latest research to a broader audience in an accessible format.

The article featured today is from Pharmaceutical Statistics, with the full article now available to read on Early View here.


Darken, P, Nyberg, J, Ballal, S, Wright, D. The attributable estimand: A new approach to account for intercurrent events. Pharmaceutical Statistics. 2020; 1–10.

In randomized controlled trials patients sometimes discontinue initially assigned therapy prematurely. This is an example of what has been called “intercurrent events” in the recently completed Addendum on estimands and sensitivity analysis in clinical trials to the guideline on statistical principles for clinical trials (ICH E9 R1). These events can affect either the interpretation or the existence of the measurements associated with the clinical question of interest. Crucial in deciding whether this intercurrent event affects the interpretation of measurements associated with the clinical question of interest is the reason for discontinuation. If a patient discontinues treatment due to an adverse event or lack of efficacy, this provides evidence that the initially randomized treatment was not successful. Whereas if a patient discontinues treatment for other reasons unrelated to their initially randomized treatment, then this is not the case. This paper describes a way of estimating the clinical question of interest that reflects this information called an attributable estimand. The approach is compared with strategies previously used to handle these events in simulations and an example in chronic obstructive pulmonary disease. The attributable estimand approach is shown to perform rationally with some advantages over alternatives in the scenarios evaluated.