Assessing fidelity to complex interventions: the icons experience

Background Assessing fidelity to complex healthcare interventions in clinical trials is a challenging area. ‘ICONS’ is a cluster randomised controlled feasibility trial of a systematic voiding programme (SVP), incorporating bladder training and prompted voiding, to promote post-stroke continence. Here we describe feasibility of one aspect of fidelity assessment: the day-to-day implementation of the SVP through analysis of clinical logs. Methods Nurses completed clinical logs daily, which included documenting: the toileting interval, proposed toileting times and times toileted. Clinical logs were sampled across trial sites. The original intention was to assess fidelity by exploring the degree of concordance between proposed times and times toileted. Initial analysis revealed the unfeasibility of this method due to documentation errors in toileting intervals and proposed times. Consequently, the planned method was changed to identification of key ‘quality indicators’ (QIs) for documentation of practice. Results The need to revise the method of measurement demonstrates the difficulty in assessing fidelity. Assessment of clinical logs revealed low levels of adherence to key quality indicators. However, it is unclear whether this indicates poor fidelity or an imprecise method of fidelity assessment. Conclusion