Intention-to-treat (ITT) analysis is a statistical method employed in randomized controlled trials (RCTs) to evaluate treatment efficacy. The fundamental principle of ITT is to analyze all participants based on their original randomized group allocation, irrespective of whether they adhered to the assigned treatment or completed the trial. This approach preserves the integrity of randomization, mitigating potential biases that may arise from excluding participants due to non-compliance, protocol deviations, or loss to follow-up.
By maintaining the original treatment groups, ITT analysis provides a conservative estimate of treatment effect, reflecting the effectiveness of the intervention under real-world conditions. This approach is particularly valuable when assessing the impact of a treatment strategy rather than the efficacy of an ideal treatment regimen. However, it is essential to acknowledge the limitations of ITT analysis, as it may underestimate the true treatment effect if a substantial number of participants deviate from the assigned treatment. In such cases, complementary analyses, such as per-protocol analysis, can provide additional insights. Nevertheless, ITT remains the gold standard for evaluating treatment efficacy in RCTs due to its ability to maintain the balance of prognostic factors achieved through randomization.