OBJECTIVE: Complex interventions are criticized for being a 'black box', which makes it difficult to determine why they succeed or fail. Recently, nine proactive primary care programmes aiming to prevent functional decline in older adults showed inconclusive effects. The aim of this study was to systematically unravel, compare and synthesize the development and evaluation of nine primary care programs within a controlled trial to further improve the development and evaluation of complex interventions.
STUDY DESIGN AND SETTING: A systematic overview of all written data on the nine proactive primary care programmes was conducted using a validated item list. The nine proactive primary care programmes involved 214 general practices throughout the Netherlands.
RESULTS: There was little or no focus on the 1) context surrounding the care programme, 2) modelling of processes and outcomes, 3) intervention fidelity and adaptation, and 4) content and evaluation of training for interventionists.
CONCLUSIONS: An in-depth analysis of the context, modelling of the processes and outcomes, measurement and reporting of intervention fidelity, and implementation of effective training for interventionists is needed to enhance the development and replication of future complex interventions.