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Health services changes: is a run-in period necessary before evaluation in randomised clinical trials?

Rathod, Trishna; Belcher, John; Montgomery, Alan A.; Salisbury, Chris; Foster, Nadine

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Trishna Rathod

John Belcher

Alan A. Montgomery

Chris Salisbury

Nadine Foster



Most randomised clinical trials (RCTs) testing a new health service do not allow a run-in period of consolidation before evaluating the new approach. Consequently, health professionals involved may feel insufficiently familiar or confident, or that new processes or systems that are integral to the service are insufficiently embedded in routine care prior to definitive evaluation in a RCT. This study aimed to determine the optimal run-in period for a new physiotherapy-led telephone assessment and treatment service known as PhysioDirect and whether a run-in was needed prior to evaluating outcomes in an RCT.

The PhysioDirect trial assessed whether PhysioDirect was as effective as usual care. Prior to the main trial, a run-in of up to 12 weeks was permitted to facilitate physiotherapists to become confident in delivering the new service. Outcomes collected from the run-in and main trial were length of telephone calls within the PhysioDirect service and patients’ physical function (SF-36v2 questionnaire) and Measure Yourself Medical Outcome Profile v2 collected at baseline and six months. Joinpoint regression determined how long it had taken call times to stabilise. Analysis of covariance determined whether patients’ physical function at six months changed from the run-in to the main trial.

Mean PhysioDirect call times (minutes) were higher in the run-in (31 (SD: 12.6)) than in the main trial (25 (SD: 11.6)). Each physiotherapist needed to answer 42 (95% CI: 20,56) calls for their mean call time to stabilise at 25 minutes per call; this took a minimum of seven weeks. For patients’ physical function, PhysioDirect was equally clinically effective as usual care during both the run-in (0.17 (95% CI: -0.91,1.24)) and main trial (-0.01 (95% CI: -0.80,0.79)).

A run-in was not needed in a large trial testing PhysioDirect services in terms of patient outcomes. A learning curve was evident in the process measure of telephone call length. This decreased during the run-in and stabilised prior to commencement of the main trial. Future trials should build in a run-in if it is anticipated that learning would have an effect on patient outcome.


Rathod, T., Belcher, J., Montgomery, A. A., Salisbury, C., & Foster, N. (2014). Health services changes: is a run-in period necessary before evaluation in randomised clinical trials?. Trials, 15(41),

Journal Article Type Article
Acceptance Date Jan 22, 2014
Publication Date Jan 30, 2014
Deposit Date Aug 16, 2017
Publicly Available Date Aug 16, 2017
Journal Trials
Electronic ISSN 1745-6215
Publisher Springer Verlag
Peer Reviewed Peer Reviewed
Volume 15
Issue 41
Keywords Health services, Learning curve, Randomised clinical trial, Run-in period
Public URL
Publisher URL


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