Table 2.
Characteristics of 39 analyses identifying trial registry entries from cohorts of published articles
| Study | Published article cohort | Registry entries found | Trial registries included | Study purpose | Study publication year | Application domain | Proportion of links by process |
|---|---|---|---|---|---|---|---|
| Mathieu [59] | 234 | 323 | ClinicalTrials.gov, ISRCTN, ICTRP, national register based on country of first author | Outcome reporting bias | 2009 | Cardiology, rheumatology, gastroenterology | Automatic = 205 Inferred = 6 Inquired = 23 |
| Chowers [105] | 49 | 60 | Unknown | Outcome reporting bias | 2009 | Anti-retroviral therapy | Unknown |
| Rasmussen [60] | 54 | 137 | ClinicalTrials.gov, ISRCTN, ICTRP, NCI-PDQ | To determine association of trial registration with the results and conclusions of published trials | 2009 | Oncology drugs | Inferred = 54 |
| Kunath [58] | 63 | 106 | ICTRP | To observe trial registration in urology journals | 2011 | Urology | Automatic = 48 Inferred = 15 |
| Ewart [56] | 135 | 124 | ISRCTN, ClinicalTrials.gov, ANZCTR, EU-CTR, National Research Register | Outcome reporting bias | 2009 | RCTs in five high-impact factor journals | Unknown |
| You [106] | 215 | 366 | ClinicalTrials.gov, ISRCTN | Outcome reporting bias | 2011 | Oncology drugs | Unknown |
| Reveiz [109] | 89 | 526 | ICTRP | Outcome reporting bias | 2012 | RCT from Latin America and Caribbean | Unknown |
| Nankervis [108] | 37 | 109 | ICTRP | Outcome reporting bias | 2012 | Eczema treatment | Automatic = 20 Inferred = 17 |
| Pinto [107] | 67 | 200 | ClinicalTrials.gov, ISRCTN, ANZCTR, national register based on country of first author | Completeness of clinical trial registration and the extent of selective reporting of outcomes in published trials | 2013 | Physical therapy | Automatic = 48 Inferred = 2 Inquired = 17 |
| van de Wetering [26] | 185 | 302 | ClinicalTrials.gov, ISRCTN, ICTRP, national register based on country of first author | To determine reporting of trial registration numbers in biomedical publications | 2012 | RCT from core clinical journals | Automatic = 166 Inquired = 19 (contact = 136, responded = 51, published = 19) |
| Hannink [110] | 218 | 327 | ClinicalTrials.gov, ISRCTN, ANZCTR and others | Outcome reporting bias | 2013 | Surgical interventions | Automatic = 218 |
| Huser [16] | 661 | 698 | ClinicalTrials.gov.gov, ISRCTN | Evaluating adherence to ICMJE policy of mandatory and timely clinical trial registration | 2013 | Trials published in five ICMJE journals | Automatic = 661 |
| Rosenthal [111] | 51 | 55 | ClinicalTrials.gov, ISRCTN, ANZCTR, ChiCTR, UMIN | Outcome reporting bias | 2013 | Surgery | Automatic, inferred, and inquired = unknown |
| Hopewell [112] | 30 | 69 | Unknown | To observe reporting characteristics of non-primary publications of results of RCTs | 2013 | RCTs from National Library of Medicine’s set of 121 core clinical journals | Automatic = 30 |
| Babu [113] | 121 | 417 | Unknown | To observe clinical trial registration in physical therapy journals | 2014 | Physical therapy journals | Automatic = 121 |
| Lee [114] | 8 | 83 | Unknown | Assessment of compliance of randomized controlled trials in trauma surgery with the CONSORT statement | 2013 | Trauma surgery | Automatic = 8 |
| Li [115] | 252 | 305 | ClinicalTrials.gov, Current Controlled Trials, NTR, ANZCTR, UMIN CTR | Outcome reporting bias | 2013 | Gastroenterology and herpetology | Automatic = 212 Inferred = 40 |
| Norris [116] | 50 | 107 | ICTRP | To determine selective outcome reporting | 2013 | Pharmacotherapy | Automatic = 30 Inferred = 20 |
| Hardt [117] | 85 | 103 | ICTRP(ClinicalTrials.gov, ISRCTN, EU-CTR, NTR, ANZCTR, DRKS, JPRNUMIN, ChiCTR, CTRI), Belgian register | To determine whether the results of registered surgical RCTs are published in journals requiring registration | 2013 | Ten highest rank surgery journals | Automatic = 68 Inferred = 17 |
| Anand [118] | 133 | 197 | ClinicalTrials.gov, ISRCTN, ANZCTR | To determine the registration and design alterations of clinical trials in clinical care | 2014 | RCT in clinical care medicine | Automatic = 105 Inferred = 28 |
| Mann [119] | 140 | 220 | ICTRP | To assess the registration status of RCTs and analyse the correspondence of registered outcomes with published outcomes | 2014 | Clinical geriatrics | Unknown |
| Walker [120] | 75 | 76 | ISRCTN, ClinicalTrials.gov, national register based on country of first author | Outcome reporting bias | 2014 | RCTs published in British Medical Journal and the Journal of American Medical Association | Automatic and inferred = unknown |
| Dekkers [121] | 29 | 54 | ICTRP | To compare non-inferiority margins defined in study protocols and trial registry records with margins reported in subsequent publications | 2015 | Non-inferiority trials submitted 2001–2005 to ethics committees in Switzerland and Netherlands | Automatic and inferred = unknown |
| Østervig [122] | 85 | 200 | ISRCTN, IRCT, EU-CTR, ChiCTR, CRiS, UMIN CTR, ClinicalTrials.gov | To check registration of randomized clinical trials | 2015 | Trials in Acta Anaesthesiologica Scandinavica | Automatic = 85 |
| Scott [62] | 160 | 181 | ISRCTN, NTR, ANZCTR, ClinicalTrials.gov, national register based on country of first author | Selective outcome reporting | 2015 | Psychiatry journals | Automatic = 150 Inferred = 6 Inquired = 4 |
| De Oliveira [123] | 107 | 201 | ISRCTN, ClinicalTrials.gov, ICTRP | Outcome reporting bias | 2015 | Anaesthesiology | Automatic, inferred, and inquired = unknown |
| Rayhill [61] | 58 | 225 | ClinicalTrials.gov and others | To assess the registration status of RCTs and analyse the correspondence of registered outcomes with published outcomes | 2015 | Core headache medicine journals | Automatic = 58 |
| Dal-Ré [124] | 175 | 178 | ClinicalTrials.gov, ISRCTN, ANZCTR, NTR, EU-CTR, CTRI, DRKS | To evaluate adherence to ICMJE policy on prospective trial registration | 2016 | Trials in high-impact journals | Unknown |
| Reveiz [125] | 52 | 144 | Registered in any international clinical trial registry | To evaluate the influence of trial registration on reporting quality of RCTs | 2010 | Highest rank journals | Unknown |
| Rongen [126] | 90 | 362 | ClinicalTrials.gov, ISRCTN, ANZCTR, NTR and others | Outcome reporting bias | 2016 | Orthopedic surgical interventions | Automatic = 90 |
| Harriman [57] | 105 | 108 | ClinicalTrials.gov, ISRCTN, ANZCTR, UMIN CTR, NTR, ChiCTR, IRCT | To assess trial registration, analysis of prospective versus retrospective registration | 2016 | Clinical trials published in the BMC series | Automatic = 105 Inquired = 0 |
| Vera-Badillo [129] | 30 | 164 | ClinicalTrials.gov | Outcome reporting bias | 2013 | Breast cancer | Automatic and inferred = unknown |
| McGee [128] | 74 | 307 | ICTRP | To determine whether trial is registered and declared registration in the publication | 2016 | Kidney transplantation | Automatic = 44 Inferred = 30 |
| Huić [127] | 149 | 152 | ClinicalTrials.gov | To determine completeness and outcome reporting bias | 2011 | RCTs published in ICMJE journals | Automatic = 149 |
| Chan [34] | 519 | 553 | Unknown | Outcome reporting bias | 2005 | RCTs indexed in PubMed | Inferred and inquired = unknown |
| Korevaar [130] | 52 | 351 | ClinicalTrials.gov, ISRCTN, national register based on country of first author | To identify the proportion of articles for which the corresponding study had been registered | 2014 | Test accuracy studies | Automatic = 27 Inferred = 11 Inquired = 14 (contact = 324, responded = 187, published = 14) |
| Jones [131] | 57 | 123 | ClinicalTrials.gov, ISRCTN, ICTRP, national register based on country of first author | Outcome reporting bias | 2012 | Emergency | Automatic = 23 Inferred = 34 |
| Smaïl-Faugeron [132] | 73 | 317 | ICTRP | To assess the registration rate of RCTs | 2015 | Oral health | Automatic = 50 Inferred = 23 |
| Riehm [133] | 40 | 76 | ISRCTN, ClinicalTrials.gov, ICTRP | Outcome reporting bias | 2015 | Psychosomatic and behavioral health | Automatic = 33 Inferred = 7 |