Asbjørn Hróbjartsson

Summary

Affiliation: Det Nordiske Cochrane Center
Country: Denmark

Publications

  1. ncbi request reprint Bias due to lack of patient blinding in clinical trials. A systematic review of trials randomizing patients to blind and nonblind sub-studies
    Asbjørn Hróbjartsson
    Nordic Cochrane Centre, Rigshospitalet, Copenhagen, Denmark, Department of Biostatistics, University of Copenhagen, Copenhagen, Denmark and Department of Orthopaedic Surgery, Herlev University Hospital, Herlev, Denmark
    Int J Epidemiol 43:1272-83. 2014
  2. ncbi request reprint Observer bias in randomized clinical trials with time-to-event outcomes: systematic review of trials with both blinded and non-blinded outcome assessors
    Asbjørn Hróbjartsson
    Nordic Cochrane Centre, Rigshospitalet Department 7811, Copenhagen, Denmark, Department of Orthopaedic Surgery, Herlev University Hospital, Copenhagen, Denmark, Department of Biostatistics, University of Copenhagen, Copenhagen, Denmark and French Cochrane Centre, Assistance Publique Hotel Dieu, Universite Paris Descartes, Paris, France
    Int J Epidemiol 43:937-48. 2014
  3. pmc Acupuncture treatment for pain: systematic review of randomised clinical trials with acupuncture, placebo acupuncture, and no acupuncture groups
    Matias Vested Madsen
    Nordic Cochrane Centre, Rigshospitalet, Department 3343, Blegdamsvej 9, DK 2100 Copenhagen, Denmark
    BMJ 338:a3115. 2009
  4. pmc Observer bias in randomized clinical trials with measurement scale outcomes: a systematic review of trials with both blinded and nonblinded assessors
    Asbjørn Hróbjartsson
    Nordic Cochrane Centre, Rigshospitalet Department 7811, Copenhagen, Denmark
    CMAJ 185:E201-11. 2013
  5. doi request reprint Observer bias in randomised clinical trials with binary outcomes: systematic review of trials with both blinded and non-blinded outcome assessors
    Asbjørn Hróbjartsson
    Nordic Cochrane Centre, Rigshospitalet Department 3343, Blegdamsvej 9, 2100 Copenhagen Ø, Denmark
    BMJ 344:e1119. 2012
  6. ncbi request reprint Clinical placebo interventions are unethical, unnecessary, and unprofessional
    Asbjørn Hróbjartsson
    Nordic Cochrane Centre, Rigshospitalet, Copenhagen
    J Clin Ethics 19:66-9. 2008
  7. ncbi request reprint Reporting on blinding in trial protocols and corresponding publications was often inadequate but rarely contradictory
    Asbjørn Hróbjartsson
    The Nordic Cochrane Centre, Rigshospitalet, Copenhagen, Denmark
    J Clin Epidemiol 62:967-73. 2009
  8. ncbi request reprint [A new scientific source of bias: SILLY bias. Analysis of citations of BMJ's Christmas articles]
    Ulrik A Felding
    Det Nordiske Cochrane Center, Rigshospitalet, København Ø
    Ugeskr Laeger 171:3784-9. 2009
  9. pmc Placebo effect studies are susceptible to response bias and to other types of biases
    Asbjørn Hróbjartsson
    The Nordic Cochrane Centre, Rigshospitalet, Copenhagen, Denmark
    J Clin Epidemiol 64:1223-9. 2011
  10. ncbi request reprint [Johannes Fibiger and the controlled clinical trial]
    Asbjørn Hróbjartsson
    Det Nordiske Cochrane Center, Rigshospitalet, DK 2100 København Ø
    Ugeskr Laeger 169:2876. 2007

Detail Information

Publications36

  1. ncbi request reprint Bias due to lack of patient blinding in clinical trials. A systematic review of trials randomizing patients to blind and nonblind sub-studies
    Asbjørn Hróbjartsson
    Nordic Cochrane Centre, Rigshospitalet, Copenhagen, Denmark, Department of Biostatistics, University of Copenhagen, Copenhagen, Denmark and Department of Orthopaedic Surgery, Herlev University Hospital, Herlev, Denmark
    Int J Epidemiol 43:1272-83. 2014
    ..Blinding patients in clinical trials is a key methodological procedure, but the expected degree of bias due to nonblinded patients on estimated treatment effects is unknown...
  2. ncbi request reprint Observer bias in randomized clinical trials with time-to-event outcomes: systematic review of trials with both blinded and non-blinded outcome assessors
    Asbjørn Hróbjartsson
    Nordic Cochrane Centre, Rigshospitalet Department 7811, Copenhagen, Denmark, Department of Orthopaedic Surgery, Herlev University Hospital, Copenhagen, Denmark, Department of Biostatistics, University of Copenhagen, Copenhagen, Denmark and French Cochrane Centre, Assistance Publique Hotel Dieu, Universite Paris Descartes, Paris, France
    Int J Epidemiol 43:937-48. 2014
    ..We wanted to evaluate the impact of nonblinded outcome assessors on estimated treatment effects in time-to-event trials...
  3. pmc Acupuncture treatment for pain: systematic review of randomised clinical trials with acupuncture, placebo acupuncture, and no acupuncture groups
    Matias Vested Madsen
    Nordic Cochrane Centre, Rigshospitalet, Department 3343, Blegdamsvej 9, DK 2100 Copenhagen, Denmark
    BMJ 338:a3115. 2009
    ..To study the analgesic effect of acupuncture and placebo acupuncture and to explore whether the type of the placebo acupuncture is associated with the estimated effect of acupuncture...
  4. pmc Observer bias in randomized clinical trials with measurement scale outcomes: a systematic review of trials with both blinded and nonblinded assessors
    Asbjørn Hróbjartsson
    Nordic Cochrane Centre, Rigshospitalet Department 7811, Copenhagen, Denmark
    CMAJ 185:E201-11. 2013
    ..We wanted to evaluate the effect of nonblinded outcome assessment on estimated effects in randomized clinical trials with outcomes that involved subjective measurement scales...
  5. doi request reprint Observer bias in randomised clinical trials with binary outcomes: systematic review of trials with both blinded and non-blinded outcome assessors
    Asbjørn Hróbjartsson
    Nordic Cochrane Centre, Rigshospitalet Department 3343, Blegdamsvej 9, 2100 Copenhagen Ø, Denmark
    BMJ 344:e1119. 2012
    ..To evaluate the impact of non-blinded outcome assessment on estimated treatment effects in randomised clinical trials with binary outcomes...
  6. ncbi request reprint Clinical placebo interventions are unethical, unnecessary, and unprofessional
    Asbjørn Hróbjartsson
    Nordic Cochrane Centre, Rigshospitalet, Copenhagen
    J Clin Ethics 19:66-9. 2008
  7. ncbi request reprint Reporting on blinding in trial protocols and corresponding publications was often inadequate but rarely contradictory
    Asbjørn Hróbjartsson
    The Nordic Cochrane Centre, Rigshospitalet, Copenhagen, Denmark
    J Clin Epidemiol 62:967-73. 2009
    ..To compare the reporting on blinding in protocols and articles describing randomized controlled trials...
  8. ncbi request reprint [A new scientific source of bias: SILLY bias. Analysis of citations of BMJ's Christmas articles]
    Ulrik A Felding
    Det Nordiske Cochrane Center, Rigshospitalet, København Ø
    Ugeskr Laeger 171:3784-9. 2009
    ..Thus, we document a new type of bias in medical research: Serious Idiopathic Loss of Ludic ironY (SILLY) bias, both in citation practices and in metaanalyses...
  9. pmc Placebo effect studies are susceptible to response bias and to other types of biases
    Asbjørn Hróbjartsson
    The Nordic Cochrane Centre, Rigshospitalet, Copenhagen, Denmark
    J Clin Epidemiol 64:1223-9. 2011
    ..The history of placebo shows that assessment of its clinical significance has a real potential to be biased. We analyze and discuss typical types of bias in studies on placebo...
  10. ncbi request reprint [Johannes Fibiger and the controlled clinical trial]
    Asbjørn Hróbjartsson
    Det Nordiske Cochrane Center, Rigshospitalet, DK 2100 København Ø
    Ugeskr Laeger 169:2876. 2007
  11. doi request reprint Blinding in randomized clinical trials: imposed impartiality
    A Hrobjartsson
    The Nordic Cochrane Centre, Rigshospitalet, Copenhagen, Denmark
    Clin Pharmacol Ther 90:732-6. 2011
    ..We encourage extensive pretrial testing of blinding procedures and explicit reporting of who was in the blinded condition and the methods used to ensure blinding...
  12. ncbi request reprint Unsubstantiated claims of large effects of placebo on pain: serious errors in meta-analysis of placebo analgesia mechanism studies
    Asbjørn Hróbjartsson
    The Nordic Cochrane Centre, Rigshospitalet, Denmark
    J Clin Epidemiol 59:336-8; discussion 339-41. 2006
  13. doi request reprint Benefits and harms of locking plate osteosynthesis in intraarticular (OTA Type C) fractures of the proximal humerus: a systematic review
    Stig Brorson
    Department of Orthopaedic Surgery, Herlev University Hospital, Denmark
    Injury 43:999-1005. 2012
    ..We systematically reviewed clinical studies assessing the benefits and harms of osteosynthesis with angle stable plates in AO/OTA Type C fractures of the proximal humerus...
  14. ncbi request reprint Coding of adverse events of suicidality in clinical study reports of duloxetine for the treatment of major depressive disorder: descriptive study
    Emma Maund
    Nordic Cochrane Centre, Rigshospitalet Department 7811, Copenhagen, Denmark
    BMJ 348:g3555. 2014
    ..To assess the effects of coding and coding conventions on summaries and tabulations of adverse events data on suicidality within clinical study reports...
  15. pmc Surgeons agree more on treatment recommendations than on classification of proximal humeral fractures
    Stig Brorson
    Department of Orthopaedic Surgery, Herlev University Hospital, Herlev Ringvej 75, 2730, Herlev, Denmark
    BMC Musculoskelet Disord 13:114. 2012
    ..However, the clinical implications of low observer agreement remain unclear. The purpose of the study was to compare the agreement on Neer classification with the agreement on treatment recommendations...
  16. pmc Reporting methods of blinding in randomized trials assessing nonpharmacological treatments
    Isabelle Boutron
    INSERM, U738, Paris, France
    PLoS Med 4:e61. 2007
    ..The purpose of this study was to systematically describe the strategies used to obtain blinding in a sample of randomized controlled trials of nonpharmacological treatment...
  17. pmc Ghost authorship in industry-initiated randomised trials
    Peter C Gøtzsche
    Nordic Cochrane Centre, Copenhagen, Denmark
    PLoS Med 4:e19. 2007
    ..The prevalence and nature of ghost authorship in industry-initiated randomised trials is not known...
  18. pmc Conflicts of interest at medical journals: the influence of industry-supported randomised trials on journal impact factors and revenue - cohort study
    Andreas Lundh
    The Nordic Cochrane Centre, Rigshospitalet, Copenhagen, Denmark
    PLoS Med 7:e1000354. 2010
    ..We investigated industry-supported trials' influence on journal impact factors and revenue...
  19. ncbi request reprint Benefits and harms in clinical trials of duloxetine for treatment of major depressive disorder: comparison of clinical study reports, trial registries, and publications
    Emma Maund
    Nordic Cochrane Centre, Rigshospitalet Dept 7811, Copenhagen, Denmark
    BMJ 348:g3510. 2014
    ....
  20. pmc Methods of blinding in reports of randomized controlled trials assessing pharmacologic treatments: a systematic review
    Isabelle Boutron
    INSERM U738, Paris, France
    PLoS Med 3:e425. 2006
    ....
  21. ncbi request reprint The use of placebo interventions in medical practice--a national questionnaire survey of Danish clinicians
    Asbjørn Hróbjartsson
    Nordic Cochrane Centre, University of Copenhagen
    Eval Health Prof 26:153-65. 2003
    ..Approximately 30% (28-36) of the clinicians believed in an effect of placebo interventions on objective outcomes, and 46% (42-50) found clinical placebo interventions generally ethically acceptable...
  22. ncbi request reprint [Constraints on publication rights in industry-initiated clinical trials--secondary publication]
    Peter C Gøtzsche
    H S Rigshospitalet, Det Nordiske Cochrane Center, DK 2100 København Ø
    Ugeskr Laeger 168:2467-9. 2006
    ..These facts were not noted in any of the trial reports. We found similar constraints on publication rights in 44 protocols from 2004. This tight sponsor control over industry-initiated trials should be changed...
  23. pmc Diagnosing displaced four-part fractures of the proximal humerus: a review of observer studies
    Stig Brorson
    Department of Orthopaedic Surgery, Herlev University Hospital, Herlev, Denmark
    Int Orthop 33:323-7. 2009
    ..Low observer agreement may challenge the clinical approach to displaced four-part fractures and poses a problem for the interpretation and generalisation of results from future randomised trials...
  24. ncbi request reprint What are the main methodological problems in the estimation of placebo effects?
    Asbjørn Hróbjartsson
    Department of Medical Philosophy and Clinical Theory, University of Copenhagen, Panum Institute, Blegdamsvej 3, DK 220 Ø Copenhagen N, Denmark
    J Clin Epidemiol 55:430-5. 2002
    ..The effect of patient-provider interaction can similarly be assessed by comparing manipulation of the patient-provider interaction with no manipulation. In both cases bias due to lack of double-blinding is a potential problem...
  25. ncbi request reprint [Selective reporting of positive outcomes in randomised trials--secondary publication.. A comparison of protocols with published reports]
    Asbjørn Hróbjartsson
    H S Rigshopitalet, Det Nordiske Cochrane Center, University Health Network Toronto, Department of Medicine
    Ugeskr Laeger 167:3189-91. 2005
    ..Selective reporting of positive outcomes is associated with bias...
  26. ncbi request reprint [What is the effect of placebo interventions? A systematic review of randomized clinical trials with placebo treated and untreated patients]
    Asbjørn Hróbjartsson
    Afdeling for Medicinsk Videskabsteori, Københavns Universitet, Panum Instituttet, DK 2200 København N
    Ugeskr Laeger 164:329-33. 2002
    ..Placebo treatments have been reported to help patients with many diseases, but the quality of the evidence supporting this belief has not been rigorously evaluated...
  27. ncbi request reprint Powerful spin in the conclusion of Wampold et al.'s re-analysis of placebo versus no-treatment trials despite similar results as in original review
    Asbjørn Hróbjartsson
    Hróbjartsson, The Nordic CochraneCentre, Rigshospitalet, Department 7112, Blegdamsvej 9, DK 2100 Copenhagen Ø
    J Clin Psychol 63:373-7. 2007
    ..95 (95% confidence interval = 0.88-1.02) versus odds ratio 0.99 (95% confidence interval = 0.81-1.23). Thus, B. E. Wampold et al.'s conclusion was not substantiated by their data, and is best characterized as powerful spin. ...
  28. pmc Locking plate osteosynthesis in displaced 4-part fractures of the proximal humerus
    Stig Brorson
    Department of Orthopaedic Surgery, Herlev University Hospital, Herlev, Denmark
    Acta Orthop 82:475-81. 2011
    ..Within the last decade, locking plate technology has been considered a breakthrough in the treatment of these complex injuries...
  29. pmc Effect of osteosynthesis, primary hemiarthroplasty, and non-surgical management for displaced four-part fractures of the proximal humerus in elderly: a multi-centre, randomised clinical trial
    Stig Brorson
    Dept of Orthopaedic Surgery, Herlev University Hospital, Herlev, Denmark
    Trials 10:51. 2009
    ..We aim to compare the effect of osteosynthesis with angle-stable plate with non-surgical management, and the effect of primary hemiarthroplasty with both osteosynthesis and non-surgical management...
  30. ncbi request reprint Data extraction errors in meta-analyses that use standardized mean differences
    Peter C Gøtzsche
    Nordic Cochrane Centre, Rigshospitalet, Copenhagen Ø, Denmark
    JAMA 298:430-7. 2007
    ..It is not known how reliable such meta-analyses are...
  31. pmc Comparison of descriptions of allocation concealment in trial protocols and the published reports: cohort study
    Julie Pildal
    Nordic Cochrane Centre, H S Rigshospitalet, DK 2100 Copenhagen, Denmark
    BMJ 330:1049. 2005
    ....
  32. ncbi request reprint Who is blinded in randomized clinical trials? A study of 200 trials and a survey of authors
    Mette Thorlund Haahr
    The Nordic Cochrane Centre, Rigshospitalet, Copenhagen, Denmark
    Clin Trials 3:360-5. 2006
    ..Insufficient blinding of persons involved in randomized clinical trials is associated with bias. The appraisal of the risk of bias is difficult without adequate information in trial reports...
  33. ncbi request reprint Training improves agreement among doctors using the Neer system for proximal humeral fractures in a systematic review
    Stig Brorson
    Amager University Hospital, Department of Orthopaedic Surgery, Italiensvej 1, Copenhagen S, Denmark
    J Clin Epidemiol 61:7-16. 2008
    ..To systematically review studies of observer agreement among doctors classifying proximal humeral fractures according to the Neer system...
  34. pmc Disagreements in meta-analyses using outcomes measured on continuous or rating scales: observer agreement study
    Britta Tendal
    Nordic Cochrane Centre, Rigshospitalet, Dept 3343, Blegdamsvej 9, DK 2100 Copenhagen, Denmark
    BMJ 339:b3128. 2009
    ..To study the inter-observer variation related to extraction of continuous and numerical rating scale data from trial reports for use in meta-analyses...
  35. pmc Spontaneous improvement in randomised clinical trials: meta-analysis of three-armed trials comparing no treatment, placebo and active intervention
    Lasse Theis Krogsbøll
    The Nordic Cochrane Centre, Rigshospitalet, Dept, 3343, Blegdamsvej 9, DK 2100 Copenhagen, Denmark
    BMC Med Res Methodol 9:1. 2009
    ..It is not known to which extent spontaneous improvement, effect of placebo and effect of active interventions contribute to the observed change from baseline, and we aimed at quantifying these contributions...
  36. pmc Divine intervention? A Cochrane review on intercessory prayer gone beyond science and reason
    Karsten Juhl Jørgensen
    Dept 3343, The Nordic Cochrane Centre, Rigshospitalet, DK 2100 Copenhagen, Denmark
    J Negat Results Biomed 8:7. 2009
    ..The review fails to live up to the high standards required for Cochrane reviews...