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Australasian Human Research Ethics Consultancy Services Pty Ltd (AHRECS)

Inclusion of Culturally and Linguistically Diverse populations in Clinical Trials:0


Nik Zeps
AHRECS Consultant

Clinical trials have enormous value to society as they provide the most robust means of working out whether or not particular treatments used to improve the health of our population work or not. Governments have a stated objective to increase participation in clinical trials based upon a series of assumptions that extend beyond their utility as a means to derive the highest level of reliable evidence about the efficacy and safety of interventions. One of these is that those people who are included derive a tangible benefit from doing so. Whilst this may not be true in all cases, after all up to 50% of people may receive an inferior treatment by definition, there is the potential for people to derive individual benefit, and it is often stated that those involved in a trial receive a higher standard of care than those not included. Certainly, the additional testing and closer scrutiny of people on a trial may equate in some instances to better care, but this should not be seen as a major driver as it could be argued that equitable care should be available as a universal right. A less discussed benefit is the connectedness and satisfaction that people may derive from making a tangible contribution to society through participation in clinical research. Furthermore, there may be indeterminate peer group benefits even if an individual does not benefit.

In an Australian study Smith et al (1) found that CALD people whose preferred language was not-English (PLNE) had the lowest participation rates in clinical trials. Whilst CALD people whose preferred language was English (PLE) had greater levels of enrollment than the PLNE group, they were still underrepresented by population. This has been described across the world and is identified as a pressing concern (2).  Understanding why this is the case is important for a number of reasons. In multiculturally diverse countries like Australia, testing interventions where a significant proportion of the population are not included could result in evidence that is not applicable to those people. This spans across biological differences which may be relevant to drug efficacy or toxicity through to interventions such as screening that may fail to be useful in those populations. Where there is evidence that participation in a clinical trial may present specific advantages there is also the issue of injustice through exclusion of a particular group or groups of persons. Certainly, from an implementation perspective, not including a diverse group of participants and analyzing for cultural and behavioral acceptability may mean that even if an intervention has merit it fails to be taken up.

The reasons for non-inclusion are likely more complex than those of language barriers, although having protocols for clinical trials that specifically exclude people who don’t have higher levels of proficiency in English do not help. It would seem that the language barrier could be soluble through providing greater resources to enable translation services, particular in areas with a clear need for this. Certainly, multi-national trials already have PICFs in multiple languages and these could be readily deployed through use of innovative technologies including eConsent processes.[1] Funders of clinical trials could make it a requirement for such inclusivity and back it up through provision of specific funding for this in any grants they award. Legal means to enforce this, whilst possible, are unlikely to drive systemic change and could have the unintended consequence of making it harder to do any trials at all in an environment already subject to extreme financial pressures.

However, a major reason for low levels of participation in clinical trials may be attributed to equity of access to clinical services in the first place. It is hard to recruit people from the general population into clinical trials, but even harder if specific members of the population don’t come to the health service in the first place. There is relatively little research on this topic and it would seem logical to do this as a priority in parallel with examining why people fail to participate in clinical trials due to language barriers. Perhaps clinical trials are simply the canary alerting us to broader inequities that need greater research and investment. Research into solutions to these inequities is accordingly a priority and may solve clinical trial participation rates as a consequence.


  1. Smith A, Agar M, Delaney G, Descallar J, Dobell-Brown K, Grand M, et al. Lower trial participation by culturally and linguistically diverse (CALD) cancer patients is largely due to language barriers. Asia Pac J Clin Oncol. 2018;14(1):52-60.
  2. Clark LT, Watkins L, Pina IL, Elmer M, Akinboboye O, Gorham M, et al. Increasing Diversity in Clinical Trials: Overcoming Critical Barriers. Curr Probl Cardiol. 2019;44(5):148-72.

Nik Zeps participated in the CCV forum at the COSA ASM. A full report of the workshop and research by the CCV and MCCabe centre is forthcoming.


This post may be cited as:

Zeps, N. (4 December 2019) Inclusion of Culturally and Linguistically Diverse populations in Clinical Trials. Research Ethics Monthly. Retrieved from:

The inclusion of retracted trials in systematic reviews: implications for patients’ safety1


After a paper has been through peer review and has been published it is the obligation of the scientific community to scrutinise an author’s work. If a serious error or misconduct is spotted the paper should be retracted and the work is removed from the evidence base. Over the past ten years there has been an exponential growth in the number of retracted papers. Much of the increase may be explained by the use of technology that has made it easier to spot duplicate publications, or fabricated data, for example. Once a paper is retracted researchers should not cite this work in future publications; this is, however, not the case. Many papers continue to be cited long after they have been retracted. Retraction Watch has a list of the ten most highly cited retracted papers. The paper that currently holds the number one spot has been cited a total of 942 times, after retraction. It is plausible that researchers are using retracted work to justify further study. This may be the scientific equivalent of “fruit of the poisonous tree”. That is to say, if the research is based on tainted work then that work is itself tainted. Authors may also include retracted work in systematic reviews and meta-analyses. In clinical disciplines – such as nursing or medicine – this is particularly worrisome.

Clinical practice should be based on the best available evidence, i.e. from systematic reviews. If a review were to include a retracted paper then the resulting meta-analysis would be contaminated and recommendations for practice emerging from the study would be unsound; ipso facto putting patients at risk because a clinician is using evidence that is flawed. To date we have found five examples in the nursing literature where this has happened. We have written to the journal editors to advise then of the error that authors have made. In our minds this is a cut and dry issue. The author has clearly made an error, potentially a serious error and one that will need to be resolved. Either the editor will need to issue an erratum or potentially retract the review (and there are examples in the literature where this has happened).

There is a second way in which a systematic review may include research that is retracted. This is when the authors of the review cite a paper that is retracted after the review is published. A more nuanced debate is perhaps required given that the review author has not made a mistake. Would it not be punitive to the author – potentially damaging their career prospects – to retract a review when they have not made a mistake? However, the inclusion of a paper that has subsequently been retracted has the potential to impact effect sizes in meta-analysis and/or review conclusions. My group undertook a study to explore how often retracted clinical trials were included in systematic reviews. The answer; more common than you might think. We followed up the citations of eleven retracted nursing trials and determined that they were included in 23 systematic reviews. Currently there is no mechanism that will alert authors (or publishing editors) that their systematic review includes a study that has subsequently been retracted. We suspect, but don’t know for certain, that in medicine and the allied health professions there are many more systematic reviews that include retracted studies. Clinical practice guidelines, such as those produced by the National Institute of Health and Care Excellence (NICE) rely on evidence from systematic reviews. And this is where our observation flips from being an interesting intellectual exercise to one that may impact patient safety. Could it be that patients are being exposed to ineffective treatments because guidelines are based on flawed reviews?

Journal editors, reviewers and researchers need to be aware and mindful that systematic reviews may contain citations that have been retracted. There is a compelling argument that the editor who issues a retraction notice for a paper also has a duty to alert authors citing this work of the retraction decision. Part of the peer review process should be checking that included references (particularly those included in meta-analysis) are not retracted, it might also be argued. Finally, not only do review authors need to ensure that they have not cited retracted papers, but they also have a responsibility to periodically check (something the Cochrane collaboration encourage authors to do) the status of included studies.

The inclusion of retracted trials is a threat to the integrity of systematic reviews. Consideration needs to be given to how the scientific community responds to the issue with the ultimate goal of keeping patients safe.

Professor Richard Gray is the editor of the Journal of Psychiatric and Mental Health Nursing. No other conflict of interest declared.

Richard Gray PhD
Professor of Clinical Nursing Practice, La Trobe University, Melbourne, Australia
Richard’s University profile |

This post may be cited as:
Gray R. (26 May 2018) The inclusion of retracted trials in systematic reviews: implications for patients’ safety. Research Ethics Monthly. Retrieved from: