BACKGROUND

Trials of complex interventions are often criticized for being difficult to interpret because the effects of apparently similar interventions vary across studies dependent on context, targeted groups, and the delivery of the intervention. The Motivational Interviewing and Medication Review in Coronary heart disease (MIMeRiC) trial is a randomized controlled trial (RCT) of an intervention aimed at improving pharmacological secondary prevention. Guidelines for the development and evaluation of complex interventions have recently highlighted the need for better reporting of the development of interventions, including descriptions of how the intervention is assumed to work, how this theory informed the process evaluation, and how the process evaluation relates to the outcome evaluation.

OBJECTIVE

This paper aims to describe how the intervention was designed and developed. The aim of the process evaluation is to better understand how and why the intervention in the MIMeRiC trial was effective or not effective.

METHODS

The research questions for evaluating the process are based on the conceptual model of change processes assumed in the intervention and will be analyzed by qualitative and quantitative methods. Quantitative data are used to evaluate the medication review in terms of drug-related problems, to describe how patients' beliefs about medicines are affected by the intervention, and to evaluate the quality of motivational interviewing. Qualitative data will be used to analyze whether patients experienced the intervention as intended, how cardiologists experienced the collaboration and intervention, and how the intervention affected patients' overall experience of care after coronary heart disease.

RESULTS

The development and piloting of the intervention are described in relation to the theoretical framework. Data for the process evaluation will be collected until March 2018. Some process evaluation questions will be analyzed before, and others will be analyzed after the outcomes of the MIMeRiC RCT are known.

CONCLUSIONS

This paper describes the framework for the design of the intervention tested in the MIMeRiC trial, development of the intervention from the pilot stage to the complete trial intervention, and the framework and methods for the process evaluation. Providing the protocol of the process evaluation allows prespecification of the processes that will be evaluated, because we hypothesize that they will determine the outcomes of the MIMeRiC trial. This protocol also constitutes a contribution to the new field of process evaluations as made explicit in health services research and clinical trials of complex interventions.