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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