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Table 1 Study characteristics including study areas, data sources, search frames, numbers and designs of included primary research, measures of comparison, and other related information for the included 33 surveys and 4 systematic reviews

From: A systematic review of comparisons between protocols or registrations and full reports in primary biomedical research

First author, publication year, journal

Study area

Data sources for protocols /registrations

Data sources for full reports

Study search frameb

Numbers of protocols (or registrations)/full reports

Study design of primary studies

Measures of comparison between protocols /registrations and full reports

Study country of primary studies

Study sample size of full reports in primary studies

Funding for the systematic review or survey

Survey (n = 33)

Al-Marzouki, 2008, The Lancet [17]

Composite areas

Protocols published on The Lancet’s website

Contacting investigators and database searching

Protocols: As of June, 2007

64/37

RCTs

Selective outcome reporting and subgroup analyses

Not reported

Not reported

Not reported

Chan, 2004, Canadian Medical Association or its licensors [19]

Composite areas

Protocols approved by Canadian Institutes of Health Research (CIHR) or Medical Research Council of Canada (MRC)

PubMed, EMBASE and the Cochrane Controlled Trials Register

Protocols: 1990–1998; Full reports: up to 2003

48/68

RCTs

Outcome reporting

Canada

Median sample size: 299

Not reported

Chan, 2004, Journal of the American Medical Association [7]

Composite areas

Protocols approved by Scientific-Ethical Committees for Copenhagen and Frederiksberg’ Denmark

Contacting trialists and by searching MEDLINE, EMBASE, and the Cochrane Controlled Trials Register

Protocols: 1994–1995; Full reports: up to May 2003

102/122

RCTS

Outcome reporting

Denmark

Median sample size: 151 for parallel RCTs; 16 for crossover RCTs

Academic funding

Chan, 2008, British Medical Journal [8]

Composite areas

Protocols approved by Scientific-Ethical Committees for Copenhagen and Frederiksberg, Denmark

PubMed, Embase, and the Cochrane Controlled Trials Register

Protocols: from January 1994 to December 1995

70/70

RCTs

Sample size calculations and data analyses

Denmark

Median sample size: 66 for per study arm

No funding received

Hartung, 2014, Annals of Internal Medicine [22]

Composite area

ClinicalTrials.gov

PubMed or the National Library of Medicine

Protocols: if trials completed before January 2009, or trials starting before July 2008 if primary completion date was unknown

110/110

RCTs

Outcome reporting, study sample and results presentations

Not reported

Median sample size: 352

Academic funding

Kasenda, 2014, British Medical Journal [9]

Composite areas

Protocols approved by six research ethics committees in Switzerland (Basel, Lucerne, Zurich, and Lausanne), Germany (Freiburg), and Canada (Hamilton)

Publications of trials from corresponding protocols

Protocols: approved between 2000 and 2003

894/515

RCTs

Subgroup analyses

Switzerland, Germany, and Canada.

Median sample size: 260

Academic funding

Redmond, 2013, Journal of Clinical Epidemiology [34]

Composite areas

Protocols submitted to Research Ethics Committee of the University Hospital Bern (Inselspital), Switzerland

CENTRAL database (Cochrane Library)

Protocols: from 1988 to 1998; Full reports: from 1990 to 2008

227/333

RCTs

Outcome reporting

Switzerland

Median sample size 330

Academic funding

Hahn, 2002, Journal of Evaluation in Clinical Practice [20]

Composite areas

Protocols from a local research ethics committee

Contacted the lead researcher

Not reported

37/15

Clinical trials

Selective reporting including study samples, outcomes, statistical plans, and result interpretations

Not reported

Not reported

Not reported

Dekkers, 2015, Journal of Clinical Epidemiology [11]

Composite areas

Protocols submitted to three research ethics committees in Switzerland and The Netherlandsa

MEDLINE via PubMed, the Cochrane Controlled Trials Register and Google Scholar

Protocols: 2001 to 2005. Full reports: up to September 2012

54/54

Non-inferiority RCTs

Noninferiority margins

Switzerland and The Netherlands

Not reported

Academic funding

Clinical Trials Registry Platform of the World Health Organization

MEDLINE via PubMed, the Cochrane Controlled Trials Register and Google Scholar

Registrations: up to March 2013. Full reports: up to September 2012

29/54

Saquib, 2013, British Medical Journal [41]

Composite areas

Registration entries, protocols obtained by personal communication, and by searching design papers

Publications in PubMed in 25 biomedical journals with the highest impact factor

Full reports: publications published in 2009

162/199

RCTs

Statistical adjustments for primary outcomes

Not reported

Not reported

No funding received

Riveros, 2013, Plos Medicine [37]

Composite areas

Clinicaltrials.gov

Medline via PubMed

Registrations: up to March 2012. Full reports: up to March 2012

600/202

RCTs

Selective and incomplete outcome reporting

Not reported

Not reported

Academic funding

Boonacker, 2011, American Journal of Epidemiology [18]

Composite areas

Grant applications awarded by the Health Care Efficiency Research Program of the Netherlands Organization for Health Research and Development (ZonMw)

Pubmed

Grant applications: from 2001 to March 2010; Full reports: up to June 2010

79/79

RCTs and observational studies

Subgroup analyses

The Netherlands

Not reported

No funding received

Rising, 2008, PLOS Medicine [36]

Composite areas

FDA (Food and Drug Administration) reviews of approved NDAs (New Drug Applications) for new molecular entities (NMEs)

PubMed and The Cochrane Library

FDA reviews: from January 2001 to December 2002. Full reports: from July 2006 through June 2007

128/164

Clinical trails

Outcome reporting, statistical plan and conclusion

Not reported

Median sample size: 392

Academic funding

Hannink, 2013, Annals of Surgery [21]

Surgery

ClinicalTrials.gov, the International Standard Randomised Controlled Trial Number Registry (ISRCTN), Australian New Zealand Clinical Trials Registry (ANZCTR), or otherregistry

PubMed in 10 general medical journals and 10 surgical journals with the highest impact factors

Registrations: between 2007 and 2012. Full reports: between 2007 and 2012

152/152

RCTs

Outcome reporting

Not reported

Not reported

Not reported

Killeen, 2014, Annals of Surgery [24]

Surgery

Clinical trials.gov, ISRCTN, WHO trial registry portal, and the national/regional trial registry of the country of origin of the trial, and by e-mailing the corresponding author

The 10 surgical journals with the highest impact factor for 2009

Registrations: from 2009 to 2010. Full reports: from 2009 to 2010

108/108

RCTs

Outcome reporting

Not reported

Not reported

Not reported

Rongen, 2016, The Journal of Bone and Joint Surgery [38]

Orthopaedics

From the published articles, and by manually searching the corresponding trial registry and/or corresponding number

PubMed in the ten orthopaedic journals with the highest impact factors

Registrations: from January 2010 through December 2014. Full reports: from January 2010 through December 2014

26/26

RCTs

Primary outcome reporting

Not reported

Not reported

No funding received

Rosenthal, 2013, Annals of Surgery [40]

Surgery

Clinicaltrials.gov, the ISRCTN registry, and the WHO International Clinical Trials Registry Platform

The Annals of Surgery, Archives of Surgery, and British Journal of Surgery

Registrations and full reports: from January 2010, and December 2010

51/51

RCTs

Study sample, intervention, outcome reporting, statistical plan, study design, time duration, and funding/sponsor/ethics approval

Not reported

Not reported

No funding received

Vedula, 2009, The New England Journal of Medicine [45]

Pharmacotherapeutic studies (for gabapentin)

Internal company documents from Parke-Davis and Pfizer

Publications for trials sponsored by Parke-Davis and Pfizer

Protocols: partly from internal company documents, up to 2008. Full reports: up to 2008

20/12

Clinical trials

Outcome reporting

Not reported

Not reported

Litigation-related consultant fees

Vedula, 2013, PLOS Medicine [10]

Pharmaco therapeutic studies (for gabapentin)

Internal company documents from Parke-Davis and Pfizer

Publications for trials sponsored by Parke-Davis and Pfizer

Protocols: partly from internal company documents, up to 2008. Full reports: up to 2008

21/11

Clinical trials

Analysis reporting

Not reported

Not reported

Litigation-related consultant fees

Norris, 2014, Res. Syn. Meth [33]

Pharmacotherapeutic studies

International Clinical Trials Registry Platform

Publications of trials included in three comparative effectiveness reviews

Registrations: from January 2005 to January 2012. Full reports: from January 2005 to January 2012

50/50

RCTs

Selective outcome reporting and selective analysis reporting

Not reported

Not reported

Academic funding

Melander, 2003, British Medical Journal [29]

Pharmaco therapeutic study (for selective serotonin reuptake inhibitors)

For short term (4–8 weeks) RCTs with approved doses, applications that were submitted to the Swedish drug regulatory authority for marketing authorization and that included all relevant information

Medline (PubMed), Embase, and PsycINFO (Psychological Abstracts)

Applications: between 1983 and 1999. Full reports: between 1983 and 1999

42/38

Clinical trials

Analysis reporting

Sweden

Not reported

No funding received

Soares, 2004, British Medical Journal [48]

Oncology

Protocols for terminated RCTs conducted by Radiation Therapy Oncology Group

Publications of terminated RCTs conducted by Radiation Therapy Oncology Group

Protocols and full reports: from 1968 onward

56/58

RCTs

Study design, statistical plan, result presentation

USA and Canada

Not reported

Academic funding

Vera-Badillo, 2013, Annals of Oncology [46]

Oncology (for breast cancer)

ClinicalTrials.gov

PubMed

Registrations and full reports: from January 1995 to August 2011

30/164

RCTs

Outcome reporting

Not reported

Not reported

Not reported

Korevaar, 2014, Clinical Chemistry [25]

Diagnostic testing

ClinicalTrials.gov

PubMed, EMBASE, and Web of Science and by contacting investigators

Protocols: between January 2006 and December 2010. Full reports: up to 2013

418/153

Clinical trials

Inclusion criteria, results presentations and outcome reporting

Most in USA and Europe

Median sample size: 172

Not reported

Li, 2013, Scandinavian Journal of Gastroenterology [26]

Gastroenterology and hepatology

From the published article, and by searching the articles in the registries

PubMed search in top five general and internal journals and top five gastroenterology and hepatology journals

Registrations: from January 2009 to December 2012. Full reports: from January 2009 to December 2012

252/305

RCTs

Primary outcome reporting

46% in Europe

Median sample size: 388 in general and internal journals; 107 in gastroenterology and hepatology journals

No funding received

Mathieu, 2009, Journal of the American Medical Association [27]

Cardiology, rheumatology, and gastroenterology

From the published article, or corresponding author, or by searchingClinicalTrials.gov, ISRCTN registry, the registry of the country of the first or corresponding author, and World Health Organization (WHO) registry search portal

MEDLINE via PubMed and the 10 general medical journals and specialty journals with the highest impact factors

Registrations: up to March 2009. Full reports: up to March 2009

147/323

RCTs

Primary outcome reporting

Not reported

Not reported

Academic funding

Maund, 2014, British Medical Journal [28]

Major depressive disorder

Applications (including protocols and clinical study reports) submitted to European Medicines Agency (EMA) for study approvaland evaluation; registrations from Clinicaltrials.gov

PubMed and Cochrane Central Register of Controlled Trials, and by contacting the manufacturer

Applications and registrations: up to March 2013. Full reports: up to March 2013

9/7

RCTs

Results presentations and interpretations

Not reported

2878 in total

Academic funding

Milette, 2011, Journal of Psychosomatic Research [31]

Psychosomatic and behavioral health

From the published article, or corresponding author, or by searchingClinicalTrials.gov, ISRCTN registry, the registry of the country of the first or corresponding author. and World Health Organization registry search portal

Publications in PubMed in Annals of Behavioral Medicine, Health Psychology, Journal of Psychosomatic Research, and Psychosomatic Medicine

Registrations: from January 2008 to September 2009. Full reports: from January 2008 to September 2009

13/63

RCTs

Outcome reporting

Not reported

Nor reported

Nor reported

Nankervis, 2012, Journal of Investigative Dermatology [32]

Dermatology

WHO International Clinical Trial Registry Platform

Global Resource of Eczema Trials (GREAT) database

Registrations: from January 2007 to July 2011. Full reports: from January 2007 to July 2011

37/109

RCTs

Outcome reporting

Not reported

Median sample size: 70 for registered trials, 60 for unregistered trials

Academic funding

Riehm, 2015, Journal of Psychosomatic Research [35]

Psychosomatic and behavioral health

From the published article, or corresponding author, or by searchingClinicalTrials.gov, ISRCTN registry, the registry of the country of the first or corresponding author. and World Health Organization registry search portal

Publications in PubMed in Annals of Behavioral Medicine, Health Psychology, Journal of Psychosomatic Research, and Psychosomatic Medicine

Registrations: from January 2013 to October 2014. Full reports: from January 2013 to October 2014

40/76

RCTs

Outcome reporting

Not reported

Not reported

No funding

Rosati, 2016, Trials [39]

Pediatrics

Clinical trial registries including the United States National Institute of Health (clinicaltrials.gov), the ISRCTN registry, the Nederlands Trials Register (NTR), the Australian and New Zealand Clinical Trial Registry (ACTRN), and the Clinical Trial Registry-India (CTRI)

20 consecutive RCTs published from July to November 2013 in the journal Pediatrics

Registrations: from July 2013 to November 2013. Full reports: from July 2013 to November 2013

20/20

RCTs

Outcome reporting, sample size, statistical plan, result interpretation

Most conducted in USA

Not reported

No funding received

Su, 2015, Trials [43]

Acupuncture

15 major international trial registries

PubMed and three Chinese databases

Registrations and full reports: up to January 2014

88/96

RCT

Outcome reporting, inclusion criteria, and comparator

Most conducted in western countries (74%)

Sample size ranged from 10 to 960

Not reported

Turner, 2012, PLoS Medicine [44]

Antipsychotic Trials

FDA reviews on eight second-generation antipsychotic drugs for the treatment of schizophrenia

PubMed and Cochrane Central Register of Controlled Trials

FDA reviews: from December 1993 to May 2005. Full reports: up to May 2010

24/20

Clinical trials

Outcome reporting, result presentation

Not reported

Not reported

Academic funding

Systematic review (n = 4)

Mhaskar, 2012, Journal of Clinical Epidemiology [30]

Oncology

Protocols of trials conducted by eight National Cancer Institute Cooperative Groups

Publications of trials conducted by eight National Cancer Institute Cooperative Groups

Protocols and full reports: Up to 2006

429/429

RCTs (Phase III)

Study sample, comparator, outcome, study design, statistical plan and randomization

Not reported

Not reported

Academic funding

You, 2012, Journal of clinical oncology [47]

Oncology

ClinicalTrials.gov and ISRCTN registry

MEDLINE via PubMed in 10 journals

Registrations: from August 2009 to April 2010. Full reports: from January 2005 to December 2009

215/366

RCTs

Outcome reporting

Not reported

Not reported

Academic funding

Hernandez, 2005, Neurosurgery [23]

Surgery (for traumatic brain injury)

Not reported

MEDLINE, EMBASE, the Cochrane Controlled Trials Register and the Cochrane Database of Systematic Reviews for RCTs

Full reports: up to April 2004

6/6

RCTs

Subgroup analyses

Most in USA and Europe

Median sample size: 463

Not reported

Smith, 2013, Pain [42]

Analgesic studies

ClinicalTrials.gov

Registered Analgesic Clinical Trials (RReACT) database

Full reports: Trials registered at ClinicalTrials.gov as of December 2011

87/87

Clinical Trials

Outcome reporting

Not reported

Median sample size: 167

Not reported

  1. RCT randomized controlled trial
  2. aEthics committees including KantonaleEthikkommission Bern; Commission d’ethique de la recherche sur l’etrehumain; and EthischeCommissieLeidsUniversitairMedisch Centrum
  3. bIndicated comparisons (protocols vs. full reports, or registrations vs. full reported) were highlighted in this column