Challenges in the design, planning and implementation of trials evaluating group interventions

Area of Science:

• Health Services Research
• Clinical Trials Methodology
• Group Dynamics in Healthcare

Background:

• Group interventions are widely used in healthcare for various purposes, including mental health recovery, behavior change, and health education.
• Randomized controlled trials (RCTs) evaluating group interventions face practical challenges distinct from individual-level interventions.
• These challenges can impact trial design, implementation, and the interpretation of results.

Purpose of the Study:

• To identify and summarize practical challenges encountered in the design and implementation of group intervention randomized controlled trials (RCTs).
• To provide an empirical basis for planning future group intervention trials by analyzing recruitment, attrition, attendance, group size, and fidelity.
• To offer insights for trialists navigating the complexities of group-based research.

Main Methods:

• A case-based approach was used, summarizing the experience of the Sheffield Trials Unit in five group intervention RCTs.
• Key aspects reviewed included participant and facilitator recruitment and attrition, group session attendance, group size, and intervention fidelity.
• Data were analyzed to identify common patterns and challenges across the included trials.

Main Results:

• Recruitment rates varied, with a median of 3.2 participants per site per month, often involving delays to form groups.
• Facilitator attrition was common, particularly when facilitators were not directly employed by the grant holder, impacting trial continuity.
• Despite targets, a median of 76.7% of participants received a 'therapeutic dose' of the intervention, and 75.3% of sessions occurred outside the ideal group size.

Conclusions:

• This study provides the first empirical evidence to guide the planning of group intervention trials.
• Investigators must anticipate recruitment delays, group size issues, and both participant and facilitator attrition.
• Careful consideration of how attendance and group size influence treatment fidelity is crucial for successful group intervention RCTs.