ArticleBMC medical research methodology2020
Using the Cochrane Central Register of Controlled Trials to identify clinical trial registration is insufficient: a cross-sectional study.
Article in BMC medical research methodology, 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 4 papers, 1 of them a synthesis that pooled it.
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
4 citing papers in PubMed, 1 synthesis or guideline pooled it.
- Clinical trial characteristics and intervention profiles for mild cognitive impairment: a systematic analysis of WHO ICTRP registry.Frontiers in pharmacology · 2026Pooled it
- Three levels of discrepancies in the records of trial sites in India, registered with the European Union Clinical Trials Register.Frontiers in medicine · 2024Article
- How do search systems impact systematic searching? A qualitative study.Journal of the Medical Library Association : JMLA · 2023Article
- Using the Cochrane Central Register of Controlled Trials to identify clinical trial registration is insufficient: a cross-sectional study.BMC medical research methodology · 2020Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
3 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundWhile conducting systemic reviews, searching for ongoing or unpublished trials is critical to address publication bias. As of April 2019, records of ongoing or unpublished randomized and/or quasi-randomized controlled trials registered in the International Clinical Trials Registry Platform (ICTRP) and ClinicalTrials.gov are available in the Cochrane Central Register of Controlled Trials (CENTRAL). These records registered in CENTRAL include studies published since the inception of ICTRP and ClinicalTrials.gov . Whether systematic reviewers can search CENTRAL to identify ongoing or unpublished trials instead of ICTRP and ClinicalTrials.gov is unknown.
methodsThis was a cross-sectional study. A consecutive sample of ongoing or unpublished studies published from June 1, 2019 to December 27, 2019 was selected from the Cochrane Reviews. The sensitivity and the number needed to read (NNR) were assessed from among the studies selected from CENTRAL instead of ICTRP and ClinicalTrials.gov and also assessed the characteristics of studies not identified by searching CENTRAL.
resultsIn total, 247 records from 50 Cochrane reviews were included; of these, 200 were identified by searching CENTRAL, whereas the remaining 47 records were not. The sensitivity of searching CENTRAL was 0.81 (95% confidence interval [CI]: 0.76, 0.85). The NNR was 115 (95% CI: 101, 133). The 47 unidentified studies were registered through ClinicalTrials.gov or ICTRP. Sixteen unidentified studies were not indexed in CENTRAL.
conclusionsFor systematic reviewers, searching CENTRAL could not substitute for searching ClinicalTrials.gov and/or ICTRP. Systematic reviewers should not only search CENTRAL but also ICTRP and ClinicalTrials.gov to identify unpublished trials.
trial registrationA pre-specified protocol was applied to conduct this study. The study was registered in the University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR). TRIAL REGISTRATION NUMBER: UMIN000038981 .
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.