A Novel Approach for Minimizing Immortal Time Bias in Observational Studies

ISPOR Europe 2022 -- Immortal time arises when the determination of a patient's treatment status involves a waiting period. A bias is introduced when this period is unaccounted for in the assessment of treatment effectiveness and/or safety. The objective was to describe a novel and innovative approach that uses propensity scores (PS) to minimize immortal time bias. Our novel approach yielded the lowest median percentage of residual bias across all approaches and our results suggest that the PS is an effective design tool for minimizing immortal time bias.