Patient preference and trials of complex interventions
Dear Sir
Campbell et al’s paper on designing and evaluating complex
interventions is a welcome analysis but fails to highlight the importance
of patient preference(Campbell et al. 2007).
One of the limitations of complex intervention trials is that of bias
arising from patient preference. Patient involvement is more active than
in a single drug trial involving the passive acceptance of drug A or drug
B, and this involvement has the potential to influence the outcome of the
trial depending on the degree of patient participation in the
intervention. Clearly it is not possible to blind patients in trials of
interventions requiring active participation, and this may introduce bias
in the estimate of the effectiveness of the intervention. Patients with
strong preference may refuse randomisation because of the risk of not
receiving their treatment of choice. If many eligible patients refused
randomisation, the results may not be generalisable and would have the
potential to weaken the external validity of a trial (Bower et al. 2005).
Brewin and Bradley have proposed the use of a ‘comprehensive cohort
design’ to evaluate interventions that involve active patient
participation (Brewin & Bradley 1989) In fact, the Medical Research
Council framework suggested the use of a preference trial design when
patients express a strong preference for an intervention in a complex
intervention trial (Medical Research Council 2000).
We have recently reported a randomised trial of a complex
intervention involving home based and hospital based cardiac
rehabilitation programmes after myocardial infarction. Using a patient
preference design in the study we were able to include an additional 126
(55%) patients which improved the external validity of our findings(Dalal
et al. 2006). Patient preference designs should be considered in trials of
complex interventions as they could improve recruitment and make the
results more generalisable.
References
Bower, P., King, M., Nazareth, I., Lampe, F., & Sibbald, B. 2005,
"Patient preferences in randomised controlled trials: conceptual framework
and implications for research", Soc Sci Med, vol. 61, no. 3, pp. 685-695.
Brewin, C. R. & Bradley, C. 1989, "Patient preferences and randomised
clinical trials", BMJ, vol. 299, no. 6694, pp. 313-315.
Campbell, N. C., Murray, E., Darbyshire, J., Emery, J., Farmer, A.,
Griffiths, F., Guthrie, B., Lester, H., Wilson, P., & Kinmonth, A. L.
2007, "Designing and evaluating complex interventions to improve health
care", BMJ, vol. 334, no. 7591, pp. 455-459.
Dalal, H. M., Evans, P. H., Campbell, J. L., Taylor, R. S., Watt, A.,
Read, K. L., Mourant, A. J., Wingham, J., Thompson, D. R., & Gray, D.
J. 2006, "Home-based versus hospital-based rehabilitation after myocardial
infarction: A randomized trial with preference arms - Cornwall Heart
Attack Rehabilitation Management Study (CHARMS)", Int.J Cardiol.
Medical Research Council 2000, A framework for development and evaluation
of Randomised Control Trials for complex interventions to improve health.
Competing interests:
None declared
Competing interests:
No competing interests
07 March 2007
Hasnain M Dalal
General Practitioner
Philip Evans, Clinical Research Fellow in Primary Care, Peninsula Medical School,Exeter EX1 2LU,Rod Taylor, Reader, Peninsula Medical School, Exeter;John Campbell, Professor of General Practice & Primary Care, Peninsula Medical School, Exeter;
Rapid Response:
Patient preference and trials of complex interventions
Dear Sir
Campbell et al’s paper on designing and evaluating complex
interventions is a welcome analysis but fails to highlight the importance
of patient preference(Campbell et al. 2007).
One of the limitations of complex intervention trials is that of bias
arising from patient preference. Patient involvement is more active than
in a single drug trial involving the passive acceptance of drug A or drug
B, and this involvement has the potential to influence the outcome of the
trial depending on the degree of patient participation in the
intervention. Clearly it is not possible to blind patients in trials of
interventions requiring active participation, and this may introduce bias
in the estimate of the effectiveness of the intervention. Patients with
strong preference may refuse randomisation because of the risk of not
receiving their treatment of choice. If many eligible patients refused
randomisation, the results may not be generalisable and would have the
potential to weaken the external validity of a trial (Bower et al. 2005).
Brewin and Bradley have proposed the use of a ‘comprehensive cohort
design’ to evaluate interventions that involve active patient
participation (Brewin & Bradley 1989) In fact, the Medical Research
Council framework suggested the use of a preference trial design when
patients express a strong preference for an intervention in a complex
intervention trial (Medical Research Council 2000).
We have recently reported a randomised trial of a complex
intervention involving home based and hospital based cardiac
rehabilitation programmes after myocardial infarction. Using a patient
preference design in the study we were able to include an additional 126
(55%) patients which improved the external validity of our findings(Dalal
et al. 2006). Patient preference designs should be considered in trials of
complex interventions as they could improve recruitment and make the
results more generalisable.
References
Bower, P., King, M., Nazareth, I., Lampe, F., & Sibbald, B. 2005,
"Patient preferences in randomised controlled trials: conceptual framework
and implications for research", Soc Sci Med, vol. 61, no. 3, pp. 685-695.
Brewin, C. R. & Bradley, C. 1989, "Patient preferences and randomised
clinical trials", BMJ, vol. 299, no. 6694, pp. 313-315.
Campbell, N. C., Murray, E., Darbyshire, J., Emery, J., Farmer, A.,
Griffiths, F., Guthrie, B., Lester, H., Wilson, P., & Kinmonth, A. L.
2007, "Designing and evaluating complex interventions to improve health
care", BMJ, vol. 334, no. 7591, pp. 455-459.
Dalal, H. M., Evans, P. H., Campbell, J. L., Taylor, R. S., Watt, A.,
Read, K. L., Mourant, A. J., Wingham, J., Thompson, D. R., & Gray, D.
J. 2006, "Home-based versus hospital-based rehabilitation after myocardial
infarction: A randomized trial with preference arms - Cornwall Heart
Attack Rehabilitation Management Study (CHARMS)", Int.J Cardiol.
Medical Research Council 2000, A framework for development and evaluation
of Randomised Control Trials for complex interventions to improve health.
Competing interests:
None declared
Competing interests: No competing interests