Comparison of registered and published intervention fidelity assessment in cluster randomised trials of public health interventions in low- and middle-income countries: systematic review protocol

Cluster randomised trials (CRTs) are a key instrument to evaluate public health interventions, particularly in low- and middle-income countries (LMICs). Fidelity assessment examines study processes to gauge whether an intervention was delivered as initially planned. Evaluation of implementation fidelity (IF) is required to establish whether the measured effects of a trial are due to the intervention itself and may be particularly important for CRTs of complex interventions. Current CRT reporting guidelines offer no guidance on IF assessment. We will systematically review the scientific literature to study current practices concerning the assessment of IF in CRTs of public health interventions in LMICs.

We will include CRTs of public health interventions in LMICs that planned or assessed IF in either the trial protocol or the main trial report (or an associated document). Search strategies use Medical Subject Headings (MESH) and text words related to CRTs, developing countries, and public health interventions. The electronic database search was developed first for MEDLINE and adapted for the following databases: EMBASE, CINAHL, PubMed, and EMB Reviews, to identify CRT reports in English, Spanish, or French published on or after January 1, 2012. To ensure availability of a study protocol, we will include CRTs reporting a registration number in the abstract. For each included study, we will compare planned versus reported assessment of IF, and consider the dimensions of IF studied, and data collection methods used to evaluate each dimension. Data will be synthesised using quantitative and narrative techniques. Risk of bias for individual studies will be assessed using the Cochrane Collaboration Risk of Bias Tool criteria and additional criteria related to CRT methods. We will investigate possible sources of heterogeneity by performing subgroup analysis. This review was not eligible for inclusion in the PROSPERO registry.

Fidelity assessment may be a key tool for making studies more reliable, internally valid, and externally generalizable. This review will provide a portrait of current practices related to the assessment of intervention fidelity in CRTs and offer suggestions for improvement. Results will be relevant to researchers, those who finance health interventions, and for decision-makers who seek the best evidence on public health interventions.