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Haq R, Molteni L, Huneke NTM. The relationship between blinding integrity and medication efficacy in randomised-controlled trials in patients with anxiety disorders: A systematic review and meta-analysis. Acta Psychiatr Scand 2024; 150:187-197. [PMID: 39126319 DOI: 10.1111/acps.13741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2024] [Revised: 07/02/2024] [Accepted: 07/22/2024] [Indexed: 08/12/2024]
Abstract
BACKGROUND Blinding is thought to minimise expectancy effects and biases in double-blind randomised-controlled trials (RCTs). However, whether blinding integrity should be assessed and reported remains debated. Furthermore, it is unknown whether blinding failure influences the outcome of RCTs in anxiety disorders. We carried out a systematic review to understand whether blinding integrity is assessed and reported in anxiolytic RCTs. A secondary aim was to explore whether blinding integrity is associated with treatment efficacy. METHOD Our protocol was pre-registered (PROSPERO CRD42022328750). We searched electronic databases for placebo-controlled, randomised trials of medication in adults with generalised and social anxiety disorders, and in panic disorder, from 1980. We extracted data regarding blinding integrity and treatment efficacy. Risk of bias was assessed with the Cochrane risk of bias tool. Where possible, we subsequently calculated Bang's Blinding Index, and assessed the association between blinding integrity and treatment effect size. RESULTS Of the 247 RCTs that met inclusion criteria, we were able to obtain assessments of blinding integrity from nine (3.64%). Overall, blinding failed in five of these trials (55.56%), but blinding was intact in 80% of placebo arms. We found a significant association between reduced blinding integrity among assessors and increased treatment effect size (betas < -1.30, p's < 0.001), but this analysis involved only four studies of which two were outlying studies. In patients, we saw a non-significant trend where reduced blinding integrity in the placebo groups was associated with increased treatment efficacy, which was not present in active medication arms. [Correction added on 19 August 2024, after first online publication: Results of the RCTs and its assessment of blinding integrity have been updated.] CONCLUSION: Consistent with work in other psychiatric disorders, blinding integrity is rarely reported in anxiolytic RCTs. Where it is reported, blinding appears to often fail. We found signals that suggest unblinding of clinician assessors (driven by two studies with complete unblinding), and of patients in placebo arms, might be associated with larger treatment effect sizes. We recommend that data regarding blinding integrity, along with the reasons patients and assessors offer for their beliefs regarding group allocation, are systematically collected in RCTs of anxiolytic treatment.
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Affiliation(s)
- Ruqayyah Haq
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Laura Molteni
- General Adult Psychiatry, Southern Health National Health Service Foundation Trust, Southampton, UK
- University Department of Psychiatry, Academic Centre, College Keep, University of Southampton, Southampton, UK
| | - Nathan T M Huneke
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- General Adult Psychiatry, Southern Health National Health Service Foundation Trust, Southampton, UK
- University Department of Psychiatry, Academic Centre, College Keep, University of Southampton, Southampton, UK
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2
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Won J, Han JY, Ji YJ, Ha D, Han BJ, Lee H. Drug trials are more likely to disclose full placebo control information than non-drug trials: A cross-sectional study of participant information leaflets of placebo-controlled trials. Integr Med Res 2024; 13:101043. [PMID: 38779540 PMCID: PMC11109310 DOI: 10.1016/j.imr.2024.101043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 04/14/2024] [Accepted: 04/16/2024] [Indexed: 05/25/2024] Open
Abstract
Background This study aimed to investigate whether placebo control is differently disclosed in drug and non-drug randomised clinical trial (RCT) participant information leaflets (PILs) and how this might affect participant blinding and direction of study outcomes. Methods PILs were obtained from trials registered in the International Standard Randomised Controlled Trial Number database via email. Placebo descriptions in PILs were categorised as Full Disclosure (FD), Partial Disclosure (PD), or Missing Information (MI). Associations between intervention type (drug or non-drug)/placebo disclosure (FD or PD/MI) and participant blinding success/trial outcome direction (positive or non-positive) were examined using a two-sided Fisher's exact test. Results Of 116 collected PILs, 56 % were for drug trials and 44 % were for non-drug trials. Among them, 88 PILs had the corresponding publications available and 68 reports specified primary outcomes. Drug trials were more likely to fully disclose placebo information than non-drug trials (92.3 % vs. 74.5 %, p < 0.05). However, the success rate of blinding was only reported in 3 out of 88 trial publications (3.4 %), precluding further analysis. Furthermore, there was no significant association between the direction of trial results and the type of intervention or placebo disclosure. Conclusion Our study findings suggest that drug and non-drug RCTs might differ in the way they reveal placebo control information. Further research is warranted to understand what leads to more common PD of placebo information in non-drug trials than drug trials and to determine the optimal placebo control disclosure in specific trial context.
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Affiliation(s)
- Jiyoon Won
- Department of Meridian & Acupoint, College of Korean Medicine, Dong-eui University, Busan, South Korea
| | - Ji-Yeon Han
- Department of Medical Science of Meridian, College of Korean Medicine, Kyung Hee University, Seoul, South Korea
| | - Yu-jin Ji
- Department of Medical Science of Meridian, College of Korean Medicine, Kyung Hee University, Seoul, South Korea
| | - Dohyung Ha
- Department of Medical Science of Meridian, College of Korean Medicine, Kyung Hee University, Seoul, South Korea
| | - Bong Jae Han
- Kyung Hee Tojung Korean Medicine Clinic, Seoul, South Korea
| | - Hyangsook Lee
- Department of Medical Science of Meridian, College of Korean Medicine, Kyung Hee University, Seoul, South Korea
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3
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Szigeti B, Heifets BD. Expectancy Effects in Psychedelic Trials. BIOLOGICAL PSYCHIATRY. COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2024; 9:512-521. [PMID: 38387698 DOI: 10.1016/j.bpsc.2024.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 02/07/2024] [Accepted: 02/08/2024] [Indexed: 02/24/2024]
Abstract
Clinical trials of psychedelic compounds like psilocybin, lysergic acid diethylamide (LSD), and N,N-dimethyltrptamine (DMT) have forced a reconsideration of how nondrug factors, such as participant expectations, are measured and controlled in mental health research. As doses of these profoundly psychoactive substances increase, so does the difficulty in concealing the treatment condition in the classic double-blind, placebo-controlled trial design. As widespread public enthusiasm for the promise of psychedelic therapy grows, so do questions regarding whether and how much trial results are biased by positive expectancy. First, we review the key concepts related to expectancy and its measurement. Then, we review expectancy effects that have been reported in both micro- and macrodose psychedelic trials from the modern era. Finally, we consider expectancy as a discrete physiological process that can be independent of, or even interact with, the drug effect. Expectancy effects can be harnessed to improve treatment outcomes and can also be actively managed in controlled studies to enhance the rigor and generalizability of future psychedelic trials.
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Affiliation(s)
- Balázs Szigeti
- Translational Psychedelic Research Program, University of California San Francisco, San Francisco, California; Centre for Psychedelic Research, Imperial College London, London, UK
| | - Boris D Heifets
- Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, California; Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, California.
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4
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Schnoll R, Wileyto EP, Bauer AM, Fox EN, Blumenthal D, Hosie Quinn M, Leone F, Huffman MD, Khan SS, Gollan JK, Papandonatos GD, Hitsman B. Seeing Through the Blind: Belief About Treatment Randomization and Smoking Cessation Outcome Among People With Current or Past Major Depressive Disorder Who Smoke in a Placebo-Controlled Trial of Varenicline. Nicotine Tob Res 2024; 26:597-603. [PMID: 37934573 PMCID: PMC11033566 DOI: 10.1093/ntr/ntad218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 09/20/2023] [Accepted: 10/27/2023] [Indexed: 11/08/2023]
Abstract
INTRODUCTION Blinding participants to randomization is a cornerstone of science. However, participant beliefs about their allocation can influence outcomes. We examined blind integrity, the association between trial arm belief and cessation, and potential mechanisms linking treatment arm and treatment arm belief among people with major depressive disorder (MDD) who smoke receiving varenicline in a placebo-controlled trial. AIMS AND METHODS 175 participants were asked at the end of treatment (EOT) if they thought they received placebo, varenicline, or were not sure. We assessed the relationship between treatment arm belief and actual treatment allocation, examined the association between treatment arm belief and EOT cessation, and evaluated changes in craving, withdrawal, side effects, depression symptoms, and smoking reward as mediators through which treatment arm was believed. RESULTS Treatment arm belief was significantly associated with actual arm assignment (χ2(2) = 13.0, p = .002). Participants in the varenicline arm were >3 times as likely to believe they were taking varenicline, versus "not sure" (RR = 3.05 [1.41-6.60], p = .005). Participants in the placebo arm were just as likely to believe they were taking placebo versus "not sure" (χ2[2] = 0.75, p = .69). Controlling for treatment arm, belief that one received varenicline was significantly associated with an increase in cessation rate (OR = 5.91 [2.06-16.92], p = .001). Change in the rewarding experience of smoking may mediate participant ability to discern getting varenicline (B = 0.077 [0.002-0.192], p < .05). CONCLUSIONS Participants receiving varenicline can discern that they received varenicline and this belief is associated with higher cessation rates. Research is needed to continue to examine how participants correctly identify their allocation to varenicline. TRIAL REGISTRATION Data come from the trial NCT02378714. IMPLICATIONS The present study adds to the sparse literature on blind integrity, particularly in the field of tobacco cessation. Randomized clinical trial participants can discern their assignment to varenicline, and believing that one received varenicline was associated with significantly higher cessation rates. Identifying treatment arm allocation may be associated with changes in the rewarding aspects of smoking that have been well documented with varenicline use. Masking allocation to varenicline is challenging. The effects of this medication in clinical trials may represent both pharmacological effects and participants' abilities to recognize that they are receiving the medication.
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Affiliation(s)
- Robert Schnoll
- Department of Psychiatry and Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA, United States
| | - E Paul Wileyto
- Department of Biostatistics, Epidemiology, and Informatics, Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania, Philadelphia, PA, United States
| | - Anna-Marika Bauer
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA, United States
| | - Erica N Fox
- Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Daniel Blumenthal
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA, United States
| | - Mackenzie Hosie Quinn
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA, United States
| | - Frank Leone
- Department of Medicine, Pulmonary, Allergy, and Critical Care Division, University of Pennsylvania, Philadelphia, PA, United States
| | - Mark D Huffman
- Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
- Department of Medicine, Washington University School of Medicine in St. Louis, St. Louis, MO, United States
- The George Institute for Global Health, University of New South Wales, Sydney, Australia
| | - Sadiya S Khan
- Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Jacqueline K Gollan
- Department of Psychiatry and Behavioral Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - George D Papandonatos
- Department of Biostatistics and Center for Statistical Sciences, Brown University School of Public Health, Providence, RI, United States
| | - Brian Hitsman
- Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
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Hohenschurz-Schmidt D, Phalip J, Chan J, Gauhe G, Soliman N, Vollert J, Lunde SJ, Vase L. Placebo analgesia in physical and psychological interventions: Systematic review and meta-analysis of three-armed trials. Eur J Pain 2024; 28:513-531. [PMID: 37985188 DOI: 10.1002/ejp.2205] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 09/18/2023] [Accepted: 11/03/2023] [Indexed: 11/22/2023]
Abstract
BACKGROUND The magnitude of placebo effects from physical and psychological 'sham' is unknown but could impact efficacy trials and treatment understanding. To quantify placebo effects, this systematic review of three-armed randomised controlled trials (RCTs) of physical and psychological interventions for pain compared outcomes in 'sham' control intervention and non-exposure arms. METHODS RCTs with treatment, 'sham' control intervention, and non-exposure groups were included, enrolling adults with any pain. A protocol was pre-registered (PROSPERO: CRD42023413324), and twelve databases searched from 2008 to July 2023. Trial methods and blinding were analysed descriptively and risk of bias assessed. Meta-analysis of pain measures at short-, medium- and long-term was performed with random-effects models of standardised mean differences (SMD).Studies were sub-grouped according to control intervention type. RESULTS Seventeen RCTs were included. The average short-term placebo effect was small (0.21 SMD, 0.1-0.33 95% CI, p = 0.0002, 1440 participants). It showed no heterogeneity (Tau2 = 0.1, I2 = 11%, p = 0.3), preventing meta-regression analyses of effect modifiers. However, sub-group analyses revealed larger placebo effects in manual control interventions compared to disabled devices and miscellaneous control interventions. Overall, placebo analgesia accounted for 39% of treatments' short-term effectiveness. No placebo effects were found at medium-term (7 RCTs, 381 participants) or long-term follow-up (3 RCTs, 173 participants). CONCLUSIONS The observed placebo analgesia has mechanistic and methodological implications, though its clinical importance may be limited. Control intervention design affects placebo effects, highlighting the importance of considering methodology in RCT interpretation. Review limitations include a small number of long-term studies and sample heterogeneity. SIGNIFICANCE This systematic review directly quantifies placebo effects from physical and psychological 'sham' control interventions and compares them to treatments' overall effectiveness. By doing so, the review enhances our understanding of placebo effects, their relative contribution in clinical trials, and their susceptibly to trial design. It poses further questions regarding the influence of blinding, participant expectations, and features of the therapeutic context. Overall, the insights provided by this review carry methodological significance and are important for the interpretation and synthesis of efficacy trials in this field.
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Affiliation(s)
- David Hohenschurz-Schmidt
- Pain Research, Department of Surgery and Cancer, Imperial College London, London, UK
- Research Department, University College of Osteopathy, London, UK
| | - Jules Phalip
- Institut ANALGESIA, Faculté de Médecine, Université Clermont Auvergne, Clermont-Ferrand, France
- CHU Clermont-Ferrand, Inserm 1107 Neuro-Dol, Service de pharmacologie médicale, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Jessica Chan
- Faculty of Medicine, Imperial College London, London, UK
| | - Greta Gauhe
- Centre for Dance Research, Coventry University, Coventry, UK
| | - Nadia Soliman
- Pain Research, Department of Surgery and Cancer, Imperial College London, London, UK
| | - Jan Vollert
- Pain Research, Department of Surgery and Cancer, Imperial College London, London, UK
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital of Schleswig-Holstein, Kiel, Germany
- Department of Anaesthesiology, Intensive Care and Pain Medicine, University Hospital Muenster, Münster, Germany
- Neurophysiology, Mannheim Center of Translational Neuroscience (MCTN), Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Sigrid Juhl Lunde
- Department of Psychology and Behavioural Sciences, School of Business and Social Sciences, Aarhus University, Aarhus, Denmark
| | - Lene Vase
- Department of Psychology and Behavioural Sciences, School of Business and Social Sciences, Aarhus University, Aarhus, Denmark
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Blease C, Colagiuri B, Locher C. Replication crisis and placebo studies: rebooting the bioethical debate. JOURNAL OF MEDICAL ETHICS 2023; 49:663-669. [PMID: 36609361 DOI: 10.1136/jme-2022-108672] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 12/30/2022] [Indexed: 06/17/2023]
Abstract
A growing body of cross-cultural survey research shows high percentages of clinicians report using placebos in clinical settings. One motivation for clinicians using placebos is to help patients by capitalising on the placebo effect's reported health benefits. This is not surprising, given that placebo studies are burgeoning, with increasing calls by researchers to ethically harness placebo effects among patients. These calls propose placebos/placebo effects offer clinically significant benefits to patients. In this paper, we argue many findings in this highly cited and 'hot' field have not been independently replicated. Evaluating the ethicality of placebo use in clinical practice involves first understanding whether placebos are efficacious clinically. Therefore, it is crucial to consider placebo research in the context of the replication crisis and what can be learnt to advance evidence-based knowledge of placebos/placebo effects and their clinical relevance (or lack thereof). In doing so, our goal in this paper is to motivate both increased awareness of replication issues and to help pave the way for advances in scientific research in the field of placebo studies to better inform ethical evidence-based practice. We argue that, only by developing a rigorous evidence base can we better understand how, if at all, placebos/placebo effects can be harnessed ethically in clinical settings.
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Affiliation(s)
- Charlotte Blease
- General Medicine and Primary Care, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
- Digital Psychiatry, Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
| | - Ben Colagiuri
- School of Psychology, University of Sydney, Sydney, New South Wales, Australia
| | - Cosima Locher
- Department of Consultation-Liaison Psychiatry and Psychosomatic Medicine, University Hospital Zurich, Zurich, Switzerland
- Psychology, Plymouth University, Plymouth, UK
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7
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Szigeti B, Phillips LD, Nutt D. Bayesian analysis of real-world data as evidence for drug approval: Remembering Sir Michael Rawlins. Br J Clin Pharmacol 2023; 89:2646-2648. [PMID: 37455605 DOI: 10.1111/bcp.15841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 06/06/2023] [Accepted: 06/14/2023] [Indexed: 07/18/2023] Open
Affiliation(s)
- Balázs Szigeti
- Centre for Psychedelic Research, Division of Psychiatry, Imperial College London, London, UK
| | | | - David Nutt
- Centre for Psychedelic Research, Division of Psychiatry, Imperial College London, London, UK
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8
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Szigeti B, Nutt D, Carhart-Harris R, Erritzoe D. The difference between 'placebo group' and 'placebo control': a case study in psychedelic microdosing. Sci Rep 2023; 13:12107. [PMID: 37495637 PMCID: PMC10371989 DOI: 10.1038/s41598-023-34938-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 05/10/2023] [Indexed: 07/28/2023] Open
Abstract
In medical trials, 'blinding' ensures the equal distribution of expectancy effects between treatment arms in theory; however, blinding often fails in practice. We use computational modelling to show how weak blinding, combined with positive treatment expectancy, can lead to an uneven distribution of expectancy effects. We call this 'activated expectancy bias' (AEB) and show that AEB can inflate estimates of treatment effects and create false positive findings. To counteract AEB, we introduce the Correct Guess Rate Curve (CGRC), a statistical tool that can estimate the outcome of a perfectly blinded trial based on data from an imperfectly blinded trial. To demonstrate the impact of AEB and the utility of the CGRC on empirical data, we re-analyzed the 'self-blinding psychedelic microdose trial' dataset. Results suggest that observed placebo-microdose differences are susceptible to AEB and are at risk of being false positive findings, hence, we argue that microdosing can be understood as active placebo. These results highlight the important difference between 'trials with a placebo-control group', i.e., when a placebo control group is formally present, and 'placebo-controlled trials', where patients are genuinely blind. We also present a new blinding integrity assessment tool that is compatible with CGRC and recommend its adoption.
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Affiliation(s)
- Balázs Szigeti
- Centre for Psychedelic Research, Imperial College London, London, UK.
| | - David Nutt
- Centre for Psychedelic Research, Imperial College London, London, UK
| | - Robin Carhart-Harris
- Psychedelics Division, Neuroscape, Department of Neurology, University of California San Francisco, San Francisco, USA
| | - David Erritzoe
- Centre for Psychedelic Research, Imperial College London, London, UK
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9
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Hohenschurz-Schmidt D, Draper-Rodi J, Vase L, Scott W, McGregor A, Soliman N, MacMillan A, Olivier A, Cherian CA, Corcoran D, Abbey H, Freigang S, Chan J, Phalip J, Sørensen LN, Delafin M, Baptista M, Medforth NR, Ruffini N, Andresen SS, Ytier S, Ali D, Hobday H, Ngurah Agung Adhiyoga Santosa AA, Vollert J, Rice AS. Blinding and sham control methods in trials of physical, psychological, and self-management interventions for pain (article II): a meta-analysis relating methods to trial results. Pain 2023; 164:509-533. [PMID: 36271798 PMCID: PMC9916063 DOI: 10.1097/j.pain.0000000000002730] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 05/16/2022] [Accepted: 06/25/2022] [Indexed: 11/26/2022]
Abstract
ABSTRACT Sham interventions in randomized clinical trials (RCTs) of physical, psychological, and self-management (PPS) therapies for pain are highly variable in design and believed to contribute to poor internal validity. However, it has not been formally tested whether the extent to which sham controls resemble the treatment under investigation consistently affects trial outcomes, such as effect sizes, differential attrition, participant expectancy, and blinding effectiveness. Placebo- or sham-controlled RCTs of PPS interventions of clinical pain populations were searched in 12 databases. The similarity of control interventions to the experimental treatment was rated across 25 features. Meta-regression analyses assessed putative links between employed control interventions, observed effect sizes in pain-related outcomes, attrition, and blinding success. The sample included 198 unique control interventions, dominated by manual therapy and chronic musculoskeletal pain research. Meta-analyses indicated small-to-moderate benefits of active treatments over control interventions, across subgroups of manual therapies, exercise, and rehabilitation, and psychological intervention trials. Multiple meta-regression modelling demonstrated that similarity between sham control and tested interventions predicted variability in pain-related outcomes, attrition, and blinding effectiveness. Influential variables were differences relating to the extent of intervention exposure, participant experience, and treatment environments. The results support the supposed link between blinding methods and effect sizes, based on a large and systematically sourced overview of methods. However, challenges to effective blinding are complex and often difficult to discern from trial reports. Nonetheless, these insights have the potential to change trial design, conduct, and reporting and will inform guideline development.
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Affiliation(s)
- David Hohenschurz-Schmidt
- Pain Research, Department Surgery & Cancer, Faculty of Medicine, Imperial College, London, United Kingdom
| | - Jerry Draper-Rodi
- Research Centre, University College of Osteopathy, London, United Kingdom
| | - Lene Vase
- Department of Psychology and Behavioural Sciences, Section for Psychology and Neuroscience, Aarhus University, Aarhus, Denmark
| | - Whitney Scott
- Health Psychology Section, Department of Psychology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
- INPUT Pain Management Unit, Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom
| | - Alison McGregor
- Human Performance Group, Department Surgery & Cancer, Faculty of Medicine, Imperial College, London, United Kingdom
| | - Nadia Soliman
- Pain Research, Department Surgery & Cancer, Faculty of Medicine, Imperial College, London, United Kingdom
| | - Andrew MacMillan
- Research Centre, University College of Osteopathy, London, United Kingdom
| | - Axel Olivier
- Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Cybill Ann Cherian
- Chemical Engineering Department, Khalifa University, Abu Dhabi, United Arab Emirates
| | | | - Hilary Abbey
- Research Centre, University College of Osteopathy, London, United Kingdom
| | - Sascha Freigang
- Department of Neurosurgery, Medical University Graz, Graz, Austria
| | - Jessica Chan
- Faculty of Medicine, Imperial College London, London, United Kingdom
| | | | - Lea Nørgaard Sørensen
- Department of Occupational Medicine, Danish Ramazzini Centre, Aarhus University Hospital, Aarhus, Denmark
| | - Maite Delafin
- The Penn Clinic, Hertfordshire, Hatfield, United Kingdom
| | - Margarida Baptista
- Wolfson Centre for Age Related Diseases, Department of Psychology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | | | - Nuria Ruffini
- National Centre Germany, Foundation C.O.M.E. Collaboration, Berlin, Germany
| | | | | | - Dorota Ali
- Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - Harriet Hobday
- Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | | | - Jan Vollert
- Pain Research, Department Surgery & Cancer, Faculty of Medicine, Imperial College, London, United Kingdom
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital of Schleswig-Holstein, Campus Kiel, Germany
- Department of Anaesthesiology, Intensive Care and Pain Medicine, University Hospital Muenster, Münster,Germany
- Neurophysiology, Mannheim Center of Translational Neuroscience (MCTN), Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Andrew S.C. Rice
- Pain Research, Department Surgery & Cancer, Faculty of Medicine, Imperial College, London, United Kingdom
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10
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Hohenschurz-Schmidt D, Draper-Rodi J, Vase L, Scott W, McGregor A, Soliman N, MacMillan A, Olivier A, Cherian CA, Corcoran D, Abbey H, Freigang S, Chan J, Phalip J, Nørgaard Sørensen L, Delafin M, Baptista M, Medforth NR, Ruffini N, Skøtt Andresen S, Ytier S, Ali D, Hobday H, Santosa AANAA, Vollert J, Rice AS. Blinding and sham control methods in trials of physical, psychological, and self-management interventions for pain (article I): a systematic review and description of methods. Pain 2023; 164:469-484. [PMID: 36265391 PMCID: PMC9916059 DOI: 10.1097/j.pain.0000000000002723] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 05/17/2022] [Accepted: 06/12/2022] [Indexed: 11/25/2022]
Abstract
ABSTRACT Blinding is challenging in randomised controlled trials of physical, psychological, and self-management therapies for pain, mainly because of their complex and participatory nature. To develop standards for the design, implementation, and reporting of control interventions in efficacy and mechanistic trials, a systematic overview of currently used sham interventions and other blinding methods was required. Twelve databases were searched for placebo or sham-controlled randomised clinical trials of physical, psychological, and self-management treatments in a clinical pain population. Screening and data extraction were performed in duplicate, and trial features, description of control methods, and their similarity to the active intervention under investigation were extracted (protocol registration ID: CRD42020206590). The review included 198 unique control interventions, published between 2008 and December 2021. Most trials studied people with chronic pain, and more than half were manual therapy trials. The described control interventions ranged from clearly modelled based on the active treatment to largely dissimilar control interventions. Similarity between control and active interventions was more frequent for certain aspects (eg, duration and frequency of treatments) than others (eg, physical treatment procedures and patient sensory experiences). We also provide an overview of additional, potentially useful methods to enhance blinding, as well as the reporting of processes involved in developing control interventions. A comprehensive picture of prevalent blinding methods is provided, including a detailed assessment of the resemblance between active and control interventions. These findings can inform future developments of control interventions in efficacy and mechanistic trials and best-practice recommendations.
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Affiliation(s)
- David Hohenschurz-Schmidt
- Pain Research, Department of Surgery and Cancer, Faculty of Medicine, Imperial College, Chelsea, London, United Kingdom
| | - Jerry Draper-Rodi
- Research Centre, University College of Osteopathy, London, United Kingdom
| | - Lene Vase
- Section for Psychology and Neuroscience, Department of Psychology and Behavioural Sciences, Aarhus University, Aarhus C, Denmark
| | - Whitney Scott
- Health Psychology Section, Department of Psychology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
- INPUT Pain Management Unit, Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom
| | - Alison McGregor
- Human Performance Group, Department of Surgery and Cancer, Faculty of Medicine, Imperial College, London, United Kingdom
| | - Nadia Soliman
- Pain Research, Department of Surgery and Cancer, Faculty of Medicine, Imperial College, Chelsea, London, United Kingdom
| | - Andrew MacMillan
- Research Centre, University College of Osteopathy, London, United Kingdom
| | - Axel Olivier
- Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Cybill Ann Cherian
- Chemical Engineering Department, Khalifa University, Abu Dhabi, United Arab Emirates
| | | | - Hilary Abbey
- Research Centre, University College of Osteopathy, London, United Kingdom
| | - Sascha Freigang
- Department of Neurosurgery, Medical University Graz, Graz, Austria
| | - Jessica Chan
- Faculty of Medicine, Imperial College London, London, United Kingdom
| | | | - Lea Nørgaard Sørensen
- Department of Occupational Medicine, Danish Ramazzini Centre, Aarhus University Hospital, Aarhus, Denmark
| | - Maite Delafin
- The Penn Clinic, Hertfordshire, Hatfield, United Kingdom
| | - Margarida Baptista
- Department of Psychology, Wolfson Centre for Age Related Diseases, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | | | - Nuria Ruffini
- National Centre Germany, Foundation C.O.M.E. Collaboration, Berlin, Germany
| | | | | | - Dorota Ali
- Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - Harriet Hobday
- Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | | | - Jan Vollert
- Pain Research, Department of Surgery and Cancer, Faculty of Medicine, Imperial College, Chelsea, London, United Kingdom
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital of Schleswig-Holstein, Kiel, Germany
- Neurophysiology, Mannheim Center of Translational Neuroscience (MCTN), Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
- Department of Anaesthesiology, Intensive Care and Pain Medicine, University Hospital Muenster, Muenster, Germany
| | - Andrew S.C. Rice
- Pain Research, Department of Surgery and Cancer, Faculty of Medicine, Imperial College, Chelsea, London, United Kingdom
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11
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Scott AJ, Sharpe L, Colagiuri B. A systematic review and meta-analysis of the success of blinding in antidepressant RCTs. Psychiatry Res 2022; 307:114297. [PMID: 34861421 DOI: 10.1016/j.psychres.2021.114297] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/14/2021] [Accepted: 11/18/2021] [Indexed: 11/29/2022]
Abstract
Successful blinding in double-blind RCTs is crucial for minimizing bias, however studies rarely report information about blinding. Among RCTs for depression, the rates of testing and success of blinding is unknown. We conducted a systematic review and meta-analysis of the rates of testing, predictors, and success of blinding in RCTs of antidepressants for depression. Following systematic search, further information about blinding assessment was requested from corresponding authors of the included studies. We reported the frequency of blinding assessment across all RCTs, and conducted logistic regression analyses to assess predictors of blinding reporting. Participant and/or investigator guesses about treatment allocation were used to calculate Bang's Blinding Index (BI). The BI between RCT arms was compared using meta-analysis. Across the 295 included trials, only 4.7% of studies assessed blinding. Pharmaceutical company sponsorship predicted blinding assessment; unsponsored trials were more likely to assess blinding. Meta-analysis suggested that blinding was unsuccessful among participants and investigators. Results suggest that blinding is rarely assessed, and often fails, among RCTs of antidepressants. This is concerning considering controversy around the efficacy of antidepressant medication. Blinding should be routinely assessed and reported in RCTs of antidepressants, and trial outcomes should be considered in light of blinding success or failure.
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Affiliation(s)
- Amelia J Scott
- School of Psychology, University of Sydney, Sydney, NSW, Australia; Department of Psychology, eCentreClinic, Macquarie University, Sydney, NSW, Australia.
| | - Louise Sharpe
- School of Psychology, University of Sydney, Sydney, NSW, Australia
| | - Ben Colagiuri
- School of Psychology, University of Sydney, Sydney, NSW, Australia
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12
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Cheng SI, Norman RM, DeMeo D, Zhong H, Turteltaub LH, McCarthy MM, Marx RG, Strickland SM, Kelly AM. The Feasibility of Blinding Intraoperative Electro-Auricular Acupuncture Under Neuraxial Anesthesia. Med Acupunct 2021; 33:286-294. [PMID: 34471447 DOI: 10.1089/acu.2021.0003] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Objective: Demand for complementary medicine, in particular, acupuncture, has increased over the past few years but widespread acceptance has been limited, in part, by the lack of high-quality studies, including lack of blinding. Acupuncture studies traditionally have difficulty with blinding as sham acupuncture can have up to a 40%-50% analgesic effect. This study randomized patients between Acupuncture and No Acupuncture (standard of care) without using sham needles. The primary outcome was adequate blinding of electro-auricular acupuncture in the intraoperative setting with secondary outcomes of pain/nausea control. Materials and Methods: Forty patients undergoing anterior cruciate ligament reconstruction were enrolled. Subjects were randomly assigned to receive acupuncture (Enhanced Electro-Auricular Trauma Protocol) or No Acupuncture during their surgeries. All patients received spinal anesthesia and intravenous midazolam, ketamine, and propofol for sedation. 1000 mg of intravenous (IV) acetaminophen and up to 30 mg of IV ketorolac were given at closure. No opioids or peripheral nerve blocks were administered intraoperatively. Results: Bang's Blinding indices were 0.2 (95% confidence interval [CI]: -0.02, 0.42) in the Acupuncture group, and 0.11 (95% CI: -0.10, 0.31) in the No Acupuncture group on postoperative day 1. Both groups had adequate blinding. There were no differences in pain scores, nausea/vomiting incidence, opioid consumption 0-24 hours, or patient satisfaction. Five patients in the No Acupuncture group received rescue blocks, while no patients in the Acupuncture group needed a rescue block (Fisher's exact test: p = 0.047). Conclusions: This study proved the primary hypothesis that adequate blinding of intraoperative acupuncture can be performed when patients are under sedation and neuraxial anesthesia. This research is registered at ClinicalTrials.gov as Clinical Trial Registration #: NCT03711734.
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Affiliation(s)
- Stephanie I Cheng
- Department of Anesthesiology, Critical Care & Pain Management, Hospital for Special Surgery, New York, NY, USA.,Department of Anesthesiology, Weill-Cornell Medical College, New York, NY, USA
| | - Ryan M Norman
- Department of Anesthesiology, Weill-Cornell Medical College, New York, NY, USA
| | - Danya DeMeo
- Department of Anesthesiology, Critical Care & Pain Management, Hospital for Special Surgery, New York, NY, USA
| | - Haoyan Zhong
- Department of Anesthesiology, Critical Care & Pain Management, Hospital for Special Surgery, New York, NY, USA
| | - Lauren H Turteltaub
- Department of Anesthesiology, Critical Care & Pain Management, Hospital for Special Surgery, New York, NY, USA.,Department of Anesthesiology, Weill-Cornell Medical College, New York, NY, USA
| | - Moira M McCarthy
- Department of Orthopedic Surgery, Sports Medicine, Hospital for Special Surgery, New York, NY, USA
| | - Robert G Marx
- Department of Orthopedic Surgery, Sports Medicine, Hospital for Special Surgery, New York, NY, USA
| | - Sabrina M Strickland
- Department of Orthopedic Surgery, Sports Medicine, Hospital for Special Surgery, New York, NY, USA
| | - Anne M Kelly
- Department of Orthopedic Surgery, Sports Medicine, Hospital for Special Surgery, New York, NY, USA
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13
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Schallhorn JM, Rose-Nussbaumer J. Masking Is Not Just for COVID-19. JAMA Ophthalmol 2021; 139:1013-1014. [PMID: 34323933 DOI: 10.1001/jamaophthalmol.2021.2706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Julie M Schallhorn
- Department of Ophthalmology and Francis I. Proctor Foundation, University of California, San Francisco, San Francisco
| | - Jennifer Rose-Nussbaumer
- Department of Ophthalmology and Francis I. Proctor Foundation, University of California, San Francisco, San Francisco.,Division of Research, Kaiser Permanente Northern California, Redwood City
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14
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Eccles R. Placebo and Side Effects Confound Clinical Trials on New Antitussives. Lung 2021; 199:319-326. [PMID: 34279718 PMCID: PMC8416890 DOI: 10.1007/s00408-021-00458-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 07/10/2021] [Indexed: 11/29/2022]
Abstract
This review discusses how the placebo effect related to treatment side effects may confound clinical trials on antitussives and specifically looks at the implications for trials on ATP antagonists. These new antitussives have distinctive side effects on the sensation of taste, and investigators have expressed concerns that this may unblind the clinical trials. Blinding is an essential component of trial design, but the degree of blinding in trials is rarely assessed. The assumptions of additivity and balance in clinical trials are discussed as important factors that allow assessment of the pharmacological activity of an antitussive. How side effects unbalance a clinical trial by amplifying the placebo effect of active treatments is discussed. The point is made that unblinding of trials invalidates any assessment of efficacy but that there is little interest or discussion about this fundamental aspect of trials. Proposals are discussed which may improve the blinding of trials and control placebo effects by changes to participant information, trial design, patient selection and use of active placebos. The issue of unblinding of clinical trials is not a new issue, but if real progress is to be made in developing new antitussives, then it is an issue that needs to be urgently addressed.
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Affiliation(s)
- Ronald Eccles
- Cardiff School of Biosciences, Cardiff University, Museum Avenue, Cardiff, CF10 3AX, UK.
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15
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Haroutounian S, Arendt-Nielsen L, Belton J, Blyth FM, Degenhardt L, Forti MD, Eccleston C, Finn DP, Finnerup NB, Fisher E, Fogarty AE, Gilron I, Hohmann AG, Kalso E, Krane E, Mohiuddin M, Moore RA, Rowbotham M, Soliman N, Wallace M, Zinboonyahgoon N, Rice ASC. International Association for the Study of Pain Presidential Task Force on Cannabis and Cannabinoid Analgesia: research agenda on the use of cannabinoids, cannabis, and cannabis-based medicines for pain management. Pain 2021; 162:S117-S124. [PMID: 34138827 PMCID: PMC8855877 DOI: 10.1097/j.pain.0000000000002266] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 03/10/2021] [Indexed: 01/08/2023]
Abstract
ABSTRACT The President of the International Association for the Study of Pain established a task force on cannabis and cannabinoid analgesia to systematically examine the evidence on (1) analgesic pharmacology of cannabinoids and preclinical evidence on their efficacy in animal models of injury-related or pathological persistent pain; (2) the clinical efficacy of cannabis, cannabinoids, and cannabis-based medicines for pain; (3) harms related to long-term use of cannabinoids; as well as (4) societal issues and policy implications related to the use of these compounds for pain management. Here, we summarize key knowledge gaps identified in the task force outputs and propose a research agenda for generating high-quality evidence on the topic. The systematic assessment of preclinical and clinical literature identified gaps in rigor of study design and reporting across the translational spectrum. We provide recommendations to improve the quality, rigor, transparency, and reproducibility of preclinical and clinical research on cannabis and cannabinoids for pain, as well as for the conduct of systematic reviews on the topic. Gaps related to comprehensive understanding of the endocannabinoid system and cannabinoid pharmacology, including pharmacokinetics and drug formulation aspects, are discussed. We outline key areas where high-quality clinical trials with cannabinoids are needed. Remaining important questions about long-term and short-term safety of cannabis and cannabinoids are emphasized. Finally, regulatory, societal, and policy challenges associated with medicinal and nonmedicinal use of cannabis are highlighted, with recommendations for improving patient safety and reducing societal harms in the context of pain management.
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Affiliation(s)
- Simon Haroutounian
- Division of Clinical and Translational Research and Washington University Pain Center. Department of Anesthesiology, Washington University School of Medicine. St Louis, MO, USA
| | - Lars Arendt-Nielsen
- Center for Neuroplasticity and Pain (CNAP) and Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, School of Medicine, Aalborg University, Aalborg, Denmark
| | - Joletta Belton
- Endless Possibilities Initiative, Fraser, CO, USA; Global Alliance of Pain Patient Advocates (GAPPA) Presidential Task Force
| | - Fiona M. Blyth
- Sydney School of Public Health, Faculty of Medicine and Health, University of Sydney, Camperdown, NSW 2006, Australia
| | - Louisa Degenhardt
- National Drug and Alcohol Research Centre, University of New South Wales, Sydney, NSW 2052, Australia
| | - Marta Di Forti
- Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London SE5 8AF, UK. National Institute for Health Research (NIHR) Mental Health Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and King’s College London, UK. South London and Maudsley NHS Mental Health Foundation Trust, London, UK
| | - Christopher Eccleston
- Centre for Pain Research. The University of Bath, Bath, UK, & Department of Clinical and Health Psychology, The University of Ghent, Belgium
| | - David P. Finn
- Pharmacology and Therapeutics, School of Medicine, Galway Neuroscience Centre and Centre for Pain Research, Human Biology Building, National University of Ireland Galway, University Road, Galway, Ireland
| | - Nanna B Finnerup
- Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Emma Fisher
- Centre for Pain Research. The University of Bath, Bath, UK
| | - Alexandra E. Fogarty
- Department of Neurology, Division of Physical Medicine & Rehabilitation, Washington University School of Medicine. St Louis, MO, USA
| | - Ian Gilron
- Departments of Anesthesiology & Perioperative Medicine and Biomedical & Molecular Sciences, Kingston Health Sciences Centre and Queen’s University; Centre for Neuroscience Studies, Queen’s University; School of Policy Studies, Queen’s University, Kingston, Canada
| | - Andrea G. Hohmann
- Department of Psychological and Brain Sciences, Program in Neuroscience, Gill Center for Biomolecular Science, Indiana University, Bloomington, IN, USA
| | - Eija Kalso
- Department of Pharmacology and SleepWell Research Programme, University of Helsinki; Department of Anaesthesiology, Intensive Care and Pain Medicine, Helsinki University Hospital
| | - Elliot Krane
- Departments of Anesthesiology, Perioperative, and Pain Medicine, & Pediatrics, Stanford University School of Medicine, Stanford, California, USA
| | - Mohammed Mohiuddin
- Department of Anesthesiology & Perioperative Medicine and, Queen’s University, Kingston, Canada
| | | | - Michael Rowbotham
- Department of Anesthesia, University of California, San Francisco, California, USA
| | - Nadia Soliman
- Pain Research, Department of Surgery & Cancer, Faculty of Medicine, Imperial College London, UK
| | - Mark Wallace
- Division of Pain Medicine, Department of Anesthesiology, University of California San Diego
| | | | - Andrew SC Rice
- Pain Research, Department of Surgery & Cancer, Faculty of Medicine, Imperial College London, UK
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16
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Freed B, Williams B, Situ X, Landsman V, Kim J, Moroz A, Bang H, Park JJ. Blinding, sham, and treatment effects in randomized controlled trials for back pain in 2000-2019: A review and meta-analytic approach. Clin Trials 2021; 18:361-370. [PMID: 33478258 PMCID: PMC8172416 DOI: 10.1177/1740774520984870] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND Blinding aims to minimize biases from what participants and investigators know or believe. Randomized controlled trials, despite being the gold standard to evaluate treatment effect, do not generally assess the success of blinding. We investigated the extent of blinding in back pain trials and the associations between participant guesses and treatment effects. METHODS We did a review with PubMed/OvidMedline, 2000-2019. Eligibility criteria were back pain trials with data available on treatment effect and participants' guess of treatment. For blinding, blinding index was used as chance-corrected measure of excessive correct guess (0 for random guess). For treatment effects, within- or between-arm effect sizes were used. Analyses of investigators' guess/blinding or by treatment modality were performed exploratorily. RESULTS Forty trials (3899 participants) were included. Active and sham treatment groups had mean blinding index of 0.26 (95% confidence interval: 0.12, 0.41) and 0.01 (-0.11, 0.14), respectively, meaning 26% of participants in active treatment believed they received active treatment, whereas only 1% in sham believed they received sham treatment, beyond chance, that is, random guess. A greater belief of receiving active treatment was associated with a larger within-arm effect size in both arms, and ideal blinding (namely, "random guess," and "wishful thinking" that signifies both groups believing they received active treatment) showed smaller effect sizes, with correlation of effect size and summary blinding indexes of 0.35 (p = 0.028) for between-arm comparison. We observed uniformly large sham treatment effects for all modalities, and larger correlation for investigator's (un)blinding, 0.53 (p = 0.046). CONCLUSION Participants in active treatments in back pain trials guessed treatment identity more correctly, while those in sham treatments tended to display successful blinding. Excessive correct guesses (that could reflect weaker blinding and/or noticeable effects) by participants and investigators demonstrated larger effect sizes. Blinding and sham treatment effects on back pain need due consideration in individual trials and meta-analyses.
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Affiliation(s)
- Brian Freed
- Department of Pain Management, Summit Medical Group, Berkeley Heights, NJ, USA
| | - Brian Williams
- Departments of Physiatry and Orthopedic Surgery, Hospital for Special Surgery, New York, NY, USA
| | - Xiaolu Situ
- Graduate Group of Biostatistics, Department of Statistics, University of California, Davis, CA, USA
| | - Victoria Landsman
- Institute for Work and Health, Toronto, ON, Canada
- Division of Biostatistics, Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada
| | - Jeehyoung Kim
- Department of Orthopedic Surgery, Seoul Sacred Heart General Hospital, Seoul, Korea
| | - Alex Moroz
- Department of Rehabilitation Medicine, New York University Grossman School of Medicine, New York, NY, USA
| | - Heejung Bang
- Graduate Group of Biostatistics, Department of Statistics, University of California, Davis, CA, USA
- Division of Biostatistics, Department of Public Health Sciences, University of California, Davis, CA, USA
- Center for Healthcare Policy and Research & Clinical and Translational Science Center Davis School of Medicine, University of California, Sacramento, CA, USA
| | - Jongbae J Park
- Department of Anesthesiology, Duke University School of Medicine, Durham, NC, USA
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17
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Ketamine and Magnesium for Refractory Neuropathic Pain: A Randomized, Double-blind, Crossover Trial. Anesthesiology 2020; 133:154-164. [PMID: 32384291 DOI: 10.1097/aln.0000000000003345] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Ketamine is often used for the management of refractory chronic pain. There is, however, a paucity of trials exploring its analgesic effect several weeks after intravenous administration or in association with magnesium. The authors hypothesized that ketamine in neuropathic pain may provide pain relief and cognitive-emotional benefit versus placebo and that a combination with magnesium may have an additive effect for 5 weeks. METHODS A randomized, double-blind, crossover, placebo-controlled study (NCT02467517) included 20 patients with neuropathic pain. Each ketamine-naïve patient received one infusion every 35 days in a random order: ketamine (0.5 mg/kg)/placebo or ketamine (0.5 mg/kg)/magnesium sulfate (3g) or placebo/placebo.The primary endpoint was the area under the curve of daily pain intensity for a period of 35 days after infusion. Secondary endpoints included pain (at 7, 15, 21 and 28 days) and health-related, emotional, sleep, and quality of life questionnaires. RESULTS Daily pain intensity was not significantly different between the three groups (n = 20) over 35 days (mean area under the curve = 185 ± 100, 196 ± 92, and 187 ± 90 pain score-days for ketamine, ketamine/magnesium, and placebo, respectively, P = 0.296). The effect size of the main endpoint was -0.2 (95% CI [-0.6 to 0.3]; P = 0.425) for ketamine versus placebo, 0.2 (95% CI [-0.3 to 0.6]; P = 0.445) for placebo versus ketamine/magnesium and -0.4 (95% CI [-0.8 to 0.1]; P = 0.119) for ketamine versus ketamine/magnesium. There were no significant differences in emotional, sleep, and quality of life measures. During placebo, ketamine, and ketamine/magnesium infusions, 10%, 20%, and 35% of patients respectively reported at least one adverse event. CONCLUSIONS The results of this trial in neuropathic pain refuted the hypothesis that ketamine provided pain relief at 5 weeks and cognitive-emotional benefit versus placebo and that a combination with magnesium had any additional analgesic effect.
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