A recent issue of BMJ highlighted the problem of missing clinical trial data from medical research, exploring both the causes and consequences of unpublished evidence.  One of the articles, from Andrew Prayle and colleagues [1], examined compliance with the US Food and Drug Administration’s ostensibly mandatory requirement that clinical trials report their results in ClinicalTrials.gov, as required by the the FDA Amendments Act (FDAAA) of 2007. Alarmingly, they found that only 22% of trials that should have reported results had actually done so.  Interestingly, industry-funded trials reported results at a higher frequency than other funders.  They conclude:

If the reporting rate does not increase, the laudable FDAAA legislation will not achieve its goal of improving the accessibility of trial results.

Fortunately for those interested in this research, the authors have ensured that their own data are available by depositing them in Dryad, where they have already been downloaded by over 100 users.

For more on the disturbing state of affairs in reporting of clinical trial data, we offer the irrepressible Ben Goldacre speaking at the Strata 2012 conference in February.

[1] Prayle AP, Hurley MN, Smyth AR (2012) Compliance with mandatory reporting of clinical trial results on ClinicalTrials.gov: cross sectional study. BMJ 343: d7373. doi:10.1136/bmj.d7373