Evidence map›Paper›PMID 42801249›Full record

ArticleClinical epidemiology2026

When to Start, How to Classify, and Whom to Include: A Methodological Assessment and Illustrative Example of the Clone-Censor-Weight Approach for Evaluating Intervention Timing in Observational Studies.

Sia Kromann Nicolaisen, Reimar Wernich Thomsen, Lars Pedersen

Abstract read
In one paragraph

Article in Clinical epidemiology, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

What it found

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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.

2 · The registry

The trial behind it

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3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

3 authors.

Sia Kromann NicolaisenDepartment of Clinical Epidemiology, Aarhus University and Aarhus University Hospital, Aarhus, Denmark.ORCID 0000-0002-6106-1945
Reimar Wernich ThomsenDepartment of Clinical Epidemiology, Aarhus University and Aarhus University Hospital, Aarhus, Denmark.ORCID 0000-0001-9135-3474
Lars PedersenDepartment of Clinical Epidemiology, Aarhus University and Aarhus University Hospital, Aarhus, Denmark.ORCID 0000-0002-9341-3888

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Introduction: Observational studies evaluating the effect of timing of an intervention, such as early versus deferred drug treatment initiation or short versus long treatment duration, often suffer from bias due to misalignment between eligibility assessment, intervention assignment, and start of follow-up. The clone-censor-weight approach aligns these time points and allows for estimation of treatment effects under predefined timing strategies. Methods: We assess the clone-censor-weight methodology and illustrate its application in an observational registry-based study of individuals with newly diagnosed diabetes, comparing infection risks under four strategies for initiation of glucose-lowering treatment: initiation within 15 days (Strategy 1), 15 days to 3 months (Strategy 2), 3 to 6 months (Strategy 3), or 6 to 12 months (Strategy 4) after diagnosis. Results: The clone-censor-weight approach established the diabetes diagnosis as the index date across all strategies. The study example included 33,857 individuals with newly diagnosed diabetes. They were cloned and assigned to all four treatment strategies, where 6439 (19.0%) clones adhered to Strategy 1, 8419 (24.9%) to Strategy 2, 5550 (16.2%) to Strategy 3, and 7539 (22.3%) to Strategy 4. The weighted absolute 5-year risks of infection were 67.0% (95% CI 65.3-68.5) for Strategy 1, 65.7% (95% CI 64.1-66.9) for Strategy 2, 66.8% (95% CI 61.8-71.9) for Strategy 3, and 67.8% (95% CI 62.8-72.7) for Strategy 4. Discussion: We have assessed the methodology and illustrated the clone-censor-weight approach in a study example evaluating intervention timing. Censoring weights should account for selection bias, estimating per-protocol effects under full adherence, but methodological challenges remain in ensuring that the weights adequately reflect both the target intervention strategies and the population they are intended to represent.

Indexed as

causal inferenceclinical inertiaclone-censor-weightobservational datasustained interventiontarget trial emulationtimingtreatment initiation

Identifiers

PMID42801249
PMCPMC13615852

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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.