The evolution of an evidence based intervention designed to improve prescribing and reduce polypharmacy in older people with multimorbidity and significant polypharmacy in primary care (SPPiRE).

Introduction: By the time an intervention is ready for evaluation in a definitive RCT the context of the evidence base may have evolved. To avoid research waste, it is imperative that intervention design and evaluation is an adaptive process incorporating emerging evidence and novel concepts. The aim of this study is to describe changes that were made to an evidence based intervention at the protocol stage of the definitive RCT to incorporate emerging evidence. Methods: The original evidence based intervention, a GP delivered web guided medication review, was modified in a five step process: Identification of core components of the original intervention. Literature review. Modification of the intervention. Pilot study. Final refinements. A framework, developed in public health research, was utilised to describe the modification process. Results: The population under investigation changed from older people with a potentially inappropriate prescription (PIP) to older people with significant polypharmacy, a proxy marker for complex multimorbidity. An assessment of treatment priorities and brown bag medication review, with a focus on deprescribing were incorporated into the original intervention. The number of repeat medicines was added as a primary outcome measure as were additional secondary patient reported outcome measures to assess treatment burden and attitudes towards deprescribing. Conclusions: A framework was used to systematically describe how and why the original intervention was modified, allowing the new intervention to build upon an effective and robustly developed intervention but also to be relevant in the context of the current evidence base.