Imperial College London

ProfessorJanetPowell

Faculty of MedicineDepartment of Surgery & Cancer

Visiting Professor
 
 
 
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Contact

 

+44 (0)20 8846 7312j.powell

 
 
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Location

 

4N17Charing Cross HospitalCharing Cross Campus

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Summary

 

Publications

Citation

BibTex format

@article{Mason:2017:10.1177/1740774517711442,
author = {Mason, AJ and Gomes, M and Grieve, R and Ulug, P and Powell, JT and Carpenter, J},
doi = {10.1177/1740774517711442},
journal = {Clinical Trials},
pages = {357--367},
title = {Development of a practical approach to expert elicitation for randomised controlled trials with missing health outcomes: Application to the IMPROVE trial},
url = {http://dx.doi.org/10.1177/1740774517711442},
volume = {14},
year = {2017}
}

RIS format (EndNote, RefMan)

TY  - JOUR
AB - Background/aims: The analyses of randomised controlled trials with missing data typically assume that, after conditioningon the observed data, the probability of missing data does not depend on the patient’s outcome, and so the data are ‘missingat random’ . This assumption is usually implausible, for example, because patients in relatively poor health may be more likelyto drop out. Methodological guidelines recommend that trials require sensitivity analysis, which is best informed by elicitedexpert opinion, to assess whether conclusions are robust to alternative assumptions about the missing data. A major barrierto implementing these methods in practice is the lack of relevant practical tools for eliciting expert opinion. We develop anew practical tool for eliciting expert opinion and demonstrate its use for randomised controlled trials with missing data.Methods: We develop and illustrate our approach for eliciting expert opinion with the IMPROVE trial (ISRCTN48334791), an ongoing multi-centre randomised controlled trial which compares an emergency endovascular strategyversus open repair for patients with ruptured abdominal aortic aneurysm. In the IMPROVE trial at 3 months post-randomisation,21% of surviving patients did not complete health-related quality of life questionnaires (assessed by EQ-5D-3L).We address this problem by developing a web-based tool that provides a practical approach for eliciting expert opinionabout quality of life differences between patients with missing versus complete data. We show how this expert opinioncan define informative priors within a fully Bayesian framework to perform sensitivity analyses that allow the missing datato depend upon unobserved patient characteristics.Results: A total of 26 experts, of 46 asked to participate, completed the elicitation exercise. The elicited quality of lifescores were lower on average for the patients with missing versus complete data, but there was considerable uncertaintyin these
AU - Mason,AJ
AU - Gomes,M
AU - Grieve,R
AU - Ulug,P
AU - Powell,JT
AU - Carpenter,J
DO - 10.1177/1740774517711442
EP - 367
PY - 2017///
SN - 1740-7745
SP - 357
TI - Development of a practical approach to expert elicitation for randomised controlled trials with missing health outcomes: Application to the IMPROVE trial
T2 - Clinical Trials
UR - http://dx.doi.org/10.1177/1740774517711442
UR - http://hdl.handle.net/10044/1/52961
VL - 14
ER -