Patient preferences and performance bias in a weight loss trial with a usual care arm

Jim McCambridge, Annik Sorhaindo, Alan Quirk, Kiran Nanchahal, Jim McCambridge, Annik Sorhaindo, Alan Quirk, Kiran Nanchahal

Abstract

Objectives: This qualitative study examines performance bias, i.e. unintended differences between groups, in the context of a weight loss trial in which a novel patient counseling program was compared to usual care in general practice.

Methods: 14/381 consecutive interviewees (6 intervention group, 8 control group) within the CAMWEL (Camden Weight Loss) effectiveness trial process study were asked about their engagement with various features of the research study and a thematic content analysis undertaken.

Results: Decisions to participate were interwoven with decisions to change behavior, to the extent that for many participants the two were synonymous. The intervention group were satisfied with their allocation. The control group spoke of their disappointment at having been offered usual care when they had taken part in the trial to access new forms of help. Reactions to disappointment involved both movements toward and away from behavior change.

Conclusion: There is a prima facie case that reactions to disappointment may introduce bias, as they lead the randomized groups to differ in ways other than the intended experimental contrast.

Practice implications: In-depth qualitative studies nested within trials are needed to understand better the processes through which bias may be introduced.

Trial registration: ClinicalTrials.gov NCT00891943.

Keywords: Behavior change; Disappointment; Patient counseling; Patient preferences; Performance bias; Research participation; Weight loss.

Copyright © 2014 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

References

    1. Higgins J.P.T., Altman D.G., Sterne J.A.C. On behalf of the Cochrane statistical methods group and the Cochrane bias methods group. Chapter 8: assessing risk of bias in included studies. In: Higgins J.P.T., Green S., editors. Cochrane handbook for systematic reviews of interventions version 510 (updated March 2011): the Cochrane collaboration. 2011. Available from .
    1. Wolfenden L., Wyse R.J., Britton B.I., Campbell K.J., Hodder R.K., Stacey F.G. Interventions for increasing fruit and vegetable consumption in children aged 5 years and under. Cochrane Database Syst Rev. 2012;11:CD008552.
    1. Cook T.D., Campbell D.T. Rand McNally; Chicago, IL: 1979. Quasi-experimentation: design and analysis issues for field settings.
    1. Kypri K., McCambridge J., Wilson A., Attia J., Sheeran P., Bowe S. Effects of study design and allocation on participant behaviour – ESDA: study protocol for a randomized controlled trial. Trials. 2011;12:42.
    1. Pocock S.J. John Wiley & Sons; Chicester: 1983. Clinical trials: a practical approach.
    1. Brewin C.R., Bradley C. Patient preferences and randomized clinical trials. Brit Med J. 1989;299:313–315.
    1. Preference Collaborative Review Group Patients’ preferences within randomised trials: systematic review and patient level meta-analysis. Brit Med J. 2008;337:a1864.
    1. King M., Nazareth I., Lampe F., Bower P., Chandler M., Morou M. Impact of participant and physician intervention preferences on randomized trials: a systematic review. J Am Med Assoc. 2005;293:1089–1099.
    1. Zelen M. Randomized consent designs for clinical trials: an update. Stat Med. 1990;9:654–656.
    1. Adamson J., Cockayne S., Puffer S., Torgerson D.J. Review of randomised trials using the post-randomised consent (Zelen's) design. Contemp Clin Trials. 2006;27:305–319.
    1. Robinson E.J., Kerr C., Stevens A., Lilford R., Braunholtz D., Edwards S. Lay conceptions of the ethical and scientific justifications for random allocation in clinical trials. Soc Sci Med. 2004;58:811–824.
    1. Robinson E.J., Kerr C.E., Stevens A.J., Lilford R.J., Braunholtz D.A., Edwards S.J. Lay public's understanding of equipoise and randomisation in randomised controlled trials. Health Technol Assess. 2005;9:1–192. [iii–iv]
    1. Mills N., Donovan J.L., Wade J., Hamdy F.C., Neal D.E., Lane J.A. Exploring treatment preferences facilitated recruitment to randomized controlled trials. J Clin Epidemiol. 2011;64:1127–1136.
    1. Wade J., Donovan J.L., Lane J.A., Neal D.E., Hamdy F.C. It's not just what you say, it's also how you say it: opening the ‘black box’ of informed consent appointments in randomised controlled trials. Soc Sci Med. 2009;68:2018–2028.
    1. Donovan J.L., Lane J.A., Peters T.J., Brindle L., Salter E., Gillatt D. Development of a complex intervention improved randomization and informed consent in a randomized controlled trial. J Clin Epidemiol. 2009;62:29–36.
    1. Featherstone K., Donovan J.L. Why don’t they just tell me straight, why allocate it? The struggle to make sense of participating in a randomised controlled trial. Soc Sci Med. 2002;55:709–719.
    1. Snowdon C., Garcia J., Elbourne D. Making sense of randomization; responses of parents of critically ill babies to random allocation of treatment in a clinical trial. Soc Sci Med. 1997;45:1337–1355.
    1. Chalmers I. Comparing like with like: some historical milestones in the evolution of methods to create unbiased comparison groups in therapeutic experiments. Int J Epidemiol. 2001;30:1156–1164.
    1. McCambridge J., Kypri K., Elbourne D. In randomisation we trust? Possible problems in experimenting with people in behavioural intervention trials. J Clin Epidemiol. 2013 [Epub ahead of print]
    1. Sarantakos S. Palgrave Macmillan; Hampshire: 2005. Social research.
    1. Nanchahal K., Power T., Holdsworth E., Hession M., Sorhaindo A., Griffiths U. A pragmatic randomised controlled trial in primary care of the Camden Weight Loss (CAMWEL) programme. Brit Med J Open. 2012;2
    1. Spanou C., Simpson S.A., Hood K., Edwards A., Cohen D., Rollnick S. Preventing disease through opportunistic, rapid engagement by primary care teams using behaviour change counselling (PRE-EMPT): protocol for a general practice-based cluster randomised trial. BMC Fam Pract. 2010;11:69.
    1. Oakley A., Strange V., Bonell C., Allen E., Stephenson J. Process evaluation in randomised controlled trials of complex interventions. Brit Med J. 2006;332:413–416.
    1. Joffe H. Thematic analysis. In: Harper D., Thompson A.R., editors. Qualitative research methods in mental health and psychotherapy: a guide for students and practitioners. John Wiley & Sons; Oxford: 2012.
    1. McCann S.K., Campbell M.K., Entwistle V.A. Reasons for participating in randomised controlled trials: conditional altruism and considerations for self. Trials. 2010;11:31.
    1. Canvin K., Jacoby A. Duty, desire or indifference? A qualitative study of patient decisions about recruitment to an epilepsy treatment trial. Trials. 2006;7:32.
    1. Kerr C.E., Robinson E.J., Lilford R.J., Edwards S.J., Braunholtz D.A., Stevens A.J. The impact of describing clinical trial treatments as new or standard. Patient Educ Couns. 2004;53:107–113.
    1. Madsen S.M., Holm S., Davidsen B., Munkholm P., Schlichting P., Riis P. Ethical aspects of clinical trials: the attitudes of participants in two non-cancer trials. J Intern Med. 2000;248:463–474.
    1. Howick J. Questioning the methodologic superiority of ‘placebo’ over ‘active’ controlled trials. Am J Bioeth. 2009;9:34–48.
    1. McCambridge J., Butor-Bhavsar K., Witton J., Elbourne D. Can research assessments themselves cause bias in behaviour change trials? A systematic review of evidence from Solomon 4-group studies. PLoS One. 2011;6:e25223.
    1. McCambridge J., Kypri K. Can simply answering research questions change behaviour? Systematic review and meta analyses of brief alcohol intervention trials. PLoS One. 2011;6:e23748.
    1. McCambridge J., de Bruin M., Witton J. The effects of demand characteristics on research participant behaviours in non-laboratory settings: a systematic review. PLoS One. 2012;7:e39116.
    1. McCambridge J., Witton J., Elbourne D.R. Systematic review of the Hawthorne effect. J Clin Epidemiol. 2013 [Epub ahead of print]
    1. Colagiuri B. Participant expectancies in double-blind randomized placebo-controlled trials: potential limitations to trial validity. Clin Trials. 2010;7:246–255.
    1. French D.P., Sutton S. Reactivity of measurement in health psychology: how much of a problem is it? What can be done about it? Brit J Health Psychol. 2010;15:453–468.

Source: PubMed

Szponzorok és közreműködők

Egészségi állapot

Kábítószer-beavatkozások

3
Iratkozz fel