ArticleCJC open2025
The Impact of Immortal Time Bias on Survival Estimates of Patients with Heart Failure with Improved Ejection Fraction.
Article in CJC open, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
0 citing papers in PubMed.
No citing paper in PubMed yet.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
12 authors.
Funding
No grant is acknowledged in the PubMed record.
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. Results: Overall, 13,085 patients were categorized into 4 groups (HFrEF, n = 2029; HFimpEF, n = 1292; HFmrEF, n = 1849; and HFpEF, n = 7915). In our scenario 2, which retained the immortal time in HFimpEF patients, the HFimpEF group exhibited a substantially lower risk of all-cause mortality compared with the HFrEF group (adjusted hazard ratio 0.30, 95% confidence interval 0.27-0.33). After applying time-varying Cox regression analysis to appropriately account for immortal time bias in our scenario 4, model 4-2, the survival benefit was notably attenuated, yielding an adjusted hazard ratio of 0.77 (95% confidence interval 0.70-0.86) for the HFimpEF group relative to the HFrEF group. Conclusions: Time-varying Cox regression analysis should be used to minimize the immortal time bias in retrospective studies concerning survival of patients with HFimpEF.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.