ArticleTrials2018
Outcome pre-specification requires sufficient detail to guard against outcome switching in clinical trials: a case study.
Article in Trials, 2018. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT02105532 (A Multi-centre, Feasibility, Cluster Randomised Controlled Trial Comparing Restrictive Versus Liberal Blood Transfusion Strategies in Adult Patients Admitted With Acute Upper Gastrointestinal Bleeding), which is not on this map. Cited by 6 papers.
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.
A Multi-centre, Feasibility, Cluster Randomised Controlled Trial Comparing Restrictive Versus Liberal Blood Transfusion Strategies in Adult Patients Admitted With Acute Upper Gastrointestinal Bleeding
Who cites it
6 citing papers in PubMed, 16 citations in OpenAlex.
- Outcome switching in cohort studies of interventions: meta-epidemiological study.BMJ (Clinical research ed.) · 2026Article
- A New Functional Threshold for Minimally Invasive Lobectomy.Annals of surgery · 2024Article
- Changes to design and analysis elements of research plans during randomised controlled trials in Australia.The Medical journal of Australia · 2022Article
- Ensuring Prevention Science Research is Synthesis-Ready for Immediate and Lasting Scientific Impact.Prevention science : the official journal of the Society for Prevention Research · 2022Article
- Article
- Comparison of Clinical Trial Changes in Primary Outcome and Reported Intervention Effect Size Between Trial Registration and Publication.JAMA network open · 2019Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
2 authors at 2 institutions in 2 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundPre-specification of outcomes is an important tool to guard against outcome switching in clinical trials. However, if the outcome is not sufficiently clearly defined, then different definitions could be applied and analysed, with only the most favourable result reported.
methodsIn order to assess the impact that differing outcome definitions could have on treatment effect estimates, we re-analysed data from TRIGGER, a cluster randomised trial comparing two red blood cell transfusion strategies for patients with acute upper gastrointestinal bleeding. We varied several aspects of the definition of further bleeding: (1) the criteria for what constitutes a further bleeding episode; (2) how further bleeding is assessed; and (3) the time-point at which further bleeding is measured.
resultsThere were marked discrepancies in the estimated odds ratios (OR) (range 0.23-0.94) and corresponding P values (range < 0.001-0.89) between different outcome definitions. At the extremes, differing outcome definitions led to markedly different conclusions; one definition led to very little evidence of a treatment effect (OR = 0.94, 95% confidence interval [CI] = 0.37-2.40, P = 0.89), while another led to very strong evidence of a treatment effect (OR = 0.23, 95% CI = 0.11-0.50, P < 0.001).
conclusionsOutcomes should be pre-specified in sufficient detail to avoid differing definitions being analysed and only the most favourable result being reported.
trial registrationClinical Trials.gov, NCT02105532 . Registered on 7 April 2014.
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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.