Intention-to-treat analysis in randomized trials: who gets counted?

Area of Science:

• Clinical Trials Methodology
• Biostatistics
• Health Services Research

Background:

• Protocol deviations are common in randomized clinical trials.
• Selecting appropriate analysis strategies is critical for valid interpretation of trial results.
• Bias can arise from different analytic approaches to efficacy and effectiveness.

Purpose of the Study:

• To discuss the rationale and implications of analysis strategy selection in randomized clinical trials concerning protocol deviations.
• To explore conceptual and methodologic approaches to bias in clinical efficacy and effectiveness assessment.
• To highlight the impact of different analytic strategies, particularly intention-to-treat analysis.

Main Methods:

• Discussion of conceptual and methodologic approaches to clinical trial analysis.
• Examination of biases related to protocol deviations.
• Illustrative examples of consequences from various analytic strategies.

Main Results:

• Intention-to-treat analysis addresses the policy question of treatment adoption, which can be more relevant than direct treatment comparison.
• Different analytic strategies have varying appropriateness depending on the intended audience.
• The choice of analysis strategy significantly impacts the interpretation of clinical trial outcomes.

Conclusions:

• The selection of analysis strategies in randomized clinical trials must carefully consider protocol deviations.
• Intention-to-treat analysis provides a robust framework for evaluating treatment policies.
• Tailoring analytic strategies to the intended audience ensures appropriate interpretation and application of trial findings.