Conceptualizing meaningful between-group difference in change over time: a demonstration of possible viewpoints

Area of Science:

• Clinical Outcome Assessment
• Health Outcomes Research
• Biostatistics

Background:

• Focus has shifted from group-level to individual-level meaningful change in health outcomes.
• Interpretation of meaningful between-group differences (MBGD) requires specific consideration.
• Randomized clinical trials (RCTs) are a primary context for evaluating MBGD.

Purpose of the Study:

• To explore and critically evaluate different conceptualizations of MBGD thresholds.
• To investigate methods for interpreting meaningful differences between treatment groups in clinical studies.
• To address the neglect of group-level meaningfulness in clinical outcome assessment.

Main Methods:

• Development and critical discussion of five distinct viewpoints on MBGD thresholds.
• Utilizing simulated data to analyze the advantages and disadvantages of each viewpoint.
• Examining thresholds in terms of patient-reported meaningful improvement and stakeholder perspectives.

Main Results:

• Applying within-individual change thresholds to group-level differences was found to be untenable.
• Several viewpoints frame MBGD based on the proportion of patients reporting meaningful improvement.
• An alternative framework suggests directly querying stakeholders on the meaningfulness of observed between-group differences.

Conclusions:

• No single, universally valid method exists for determining MBGD thresholds.
• Purely data-driven thresholds are insufficient; subjective stakeholder judgment is necessary.
• Further research is needed to develop robust methods for establishing MBGD.