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# Adverse Events Unreported in Published Studies: Research
- URL: https://www.fdaweb.com/adverse-events-unreported-in-published-studies-research/
- Published: 2016-09-21T12:00:00.000Z
- Updated: 2026-09-14T21:34:02.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5136873

UK researchers say there is strong evidence that much of the information on adverse events remains unpublished and that the number and range of adverse events is higher in unpublished than in published versions of the same study. [Writing](http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1002127&ref=fdaweb.com) in the open-source journal *PLOS Medicine*, the authors say their findings suggest that researchers should look beyond journal publications for information on treatment side effects. “These findings also support the need for the drug industry to release full data on side effects so that a complete picture can be given to health professionals, policy makers, and patients,” the article says.

Using a number of databases and other sources, the researchers found 28 studies that provided information on the amount of data on side effects in published journal articles as compared to other sources such as Web sites, conference, and industry-held data. “A lower number of side effects are generally reported in published studies than unpublished studies, and a wider range of named side effects are reported in unpublished than published studies,” the report says.

The authors say they identified serious concerns about the substantial amount of unpublished adverse events data that may be difficult to access or are “hidden” from healthcare workers and members of the public. “The extent of ‘hidden’ data has important implications for clinicians and patients who may have to rely on (incomplete) published data when making evidence-based decisions on benefit versus harm,” they write. “Our findings suggest that poor reporting of harms data, selective outcome reporting, and publication bias are very serious threats to the validity of systematic reviews and meta-analyses of harms…. Our review demonstrates the urgent need to progress towards full disclosure and unrestricted access to information from clinical trials.”