The Impact of Immortal Time Bias on Survival Estimates of Patients with Heart Failure with Improved Ejection Fraction.

ABSTRACT:

Background

The influence of immortal time bias on estimates of survival of heart failure (HF) patients with improved ejection fraction (HFimpEF) has not been well elucidated.

Methods

This retrospective cohort study collected patients who had ever been hospitalized owing to HF between January 2012 and June 2022 at National Taiwan University Hospital (NTUH), the NTUH Hsin-Chu branch, or the NTUH Yun-Lin branch. Patients were classified as follows: (i) HF with reduced ejection fraction (HFrEF); (ii) HFimpEF; (iii) HF with mildly reduced ejection fraction (HFmrEF); and (iv) HF with preserved ejection fraction (HFpEF). Four different clinical scenarios were designed to illustrate the impact of the immortal time bias in estimating the long-term survival of patients with HFimpEF.

SUBMITTER: Lai CL 

PROVIDER: S-EPMC12800798 | biostudies-literature | 2025 Dec

REPOSITORIES: biostudies-literature