Intended for healthcare professionals

CCBYNC Open access

Impact of document type on reporting quality of clinical drug trials: a comparison of registry reports, clinical study reports, and journal publications

BMJ 2012; 344 doi: (Published 03 January 2012) Cite this as: BMJ 2012;344:d8141
  1. Beate Wieseler, head of department of drug assessment,
  2. Michaela F Kerekes, data manager,
  3. Volker Vervoelgyi, researcher,
  4. Natalie McGauran, researcher,
  5. Thomas Kaiser, head of department of drug assessment
  1. 1Institute for Quality and Efficiency in Health Care, Dillenburger Strasse 27, 51105 Cologne, Germany
  1. Correspondence to: B Wieseler beate.wieseler{at}
  • Accepted 8 December 2011


Objective To investigate to what extent three types of documents for reporting clinical trials provide sufficient information for trial evaluation.

Design Retrospective analysis

Data sources Primary studies and corresponding documents (registry reports, clinical study reports, journal publications) from 16 health technology assessments of drugs conducted by the German Institute for Quality and Efficiency in Health Care between 2006 and February 2011.

Data analysis We assessed reporting quality for each study and each available document for six items on methods and six on outcomes, and dichotomised them as “completely reported” or “incompletely reported.” For each document type, we calculated the proportion of studies with complete reporting for methods and outcomes, per item and overall, and compared the findings.

Results We identified 268 studies. Publications, study reports and registry reports were available for 192 (72%), 101 (38%), and 78 (29%) studies, respectively. Reporting quality was highest in study reports, which overall provided complete information for 90% of items (1086/1212). Registry reports provided more complete information on outcomes than on methods (overall 330/468 (71%) v 147/468 (31%)); the same applied to publications (594/1152 (52%) v 458/1152 (40%)). In the matched pairs analysis, reporting quality was poorer in registry reports than in study reports for overall methods and outcomes (P<0.001 in each case). Compared with publications, reporting quality was poorer in registry reports for overall methods (P<0.001), but better for outcomes (P=0.005).

Conclusion Registry reports and publications insufficiently report clinical trials but may supplement each other. Measures to improve reporting include the mandatory worldwide implementation of adequate standards for results registration.


  • The authors thank Brian and Katrin McGauran for their comments on the manuscript.

  • Contributors: BW and TK conceived the idea for the analysis. MFK extracted and coded the data. VV checked the data and codings and prepared the statistical analysis. BW drafted the first version of the paper, which NM revised. All authors contributed to data interpretation and to critical revision of the paper and have seen and approved the final version. BW is the guarantor of the paper.

  • Funding: This work was supported by IQWiG.

  • Competing interests: All authors have completed the Unified Competing Interest form at (available on request from the corresponding author) and declare no support from any company for the submitted work. All authors are employees of IQWiG. In order to produce unbiased health technology assessment reports, the institute depends on access to all of the relevant data on the topic under investigation. The authors therefore support the mandatory worldwide establishment of trial registries and study results databases as well as the implementation of reporting standards for clinical trials.

  • Data sharing: No additional data available.

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-commercial License, which permits use, distribution, and reproduction in any medium, provided the original work is properly cited, the use is non commercial and is otherwise in compliance with the license. See: and

View Full Text