A search for relevant contextual factors in intervention studies: a stepwise approach with online information

OBJECTIVE: The aim of the present study is to describe a stepwise approach to study which contextual factors might moderate the effect of healthcare interventions and to test feasibility of this approach within the D-SCOPE project. DESIGN: Exploratory case study. SETTING: In the D-SCOPE project, a complex intervention by means of home visits was set up to improve access to tailored care in three municipalities (Ghent, Knokke-Heist and Tienen). METHODS: One designed and tested an approach including five steps: (1) a theoretical/conceptual discussion of relevant contextual factor domains was held; (2) a search was done to find appropriate web-based public datasets which covered these topics with standardised information; (3) a list of all identified contextual factors was made (inventory); (4) to reduce the long list of contextual factors, a concise list of most relevant contextual factors was developed based on the opinion of two independent reviewers and (5) a nominal grouping technique (NGT) was applied. RESULTS: Three public web-based datasets were found resulting in an inventory of 157 contextual factors. After the selection by two independent reviewers, 41 contextual factors were left over and presented in a NGT which selected 10 contextual factors. The NGT included seven researchers, all familiar with the D-SCOPE intervention, with various educational backgrounds and expertise and lasted approximately 1 hour. CONCLUSION: The present study shows that a five-step approach is feasible to determine relevant contextual factors that might affect the results of an intervention study. Such information may be used to correct for in the statistical analyses and for interpretation of the outcomes of intervention studies. NCT03168204