Almost one in five clinical trials evaluating physiotherapy interventions for low back pain excluded people due to lack of language proficiency

People need to communicate fluently to adequately participate in some physiotherapy interventions, for example, interventions for health promotion or behaviour modification. Language proficiency is also a requirement for participating in most clinical trials. This prerequisite may cause a hindrance to people from culturally and linguistic diverse backgrounds who have language barriers to access clinical treatments. Lack of language proficiency prevents them from fully engaging in physiotherapy interventions and being represented in clinical trials.

A meta-epidemiological study was recently published that identified physiotherapy trials which specified language proficiency as an eligibility criterion. Randomised controlled trials evaluating at least one type of physiotherapy intervention for low back pain were retrieved from the Physiotherapy Evidence Database (PEDro), LILACS and SciELO from inception to May 2021. The study compared the characteristics of the trials (e.g., country of recruitment, category of intervention, year of publication), and estimated the proportion of people who were excluded from these trials due to lack of language proficiency.

The study included 2,555 trials, of which 2,538 were indexed in PEDro. A language-grounded eligibility criterion was specified in 463 (18.1%) trials. The proportion was higher in trials that were conducted in North America and Europe, published after 2000, investigated cognitive and behavioural interventions, and had large sample sizes. Of these 463 trials, 75 trials (16.2%) reported that a total of 2,152 people were excluded due to lack of language proficiency, equivalent to 12.5% of randomised participants.

The reason for a language-grounded eligibility criterion was justified in 41 trials; language proficiency was required to obtain informed consent, complete questionnaires, read the information or materials, participate in interviews or group discussion, follow treatment instructions, and communicate with therapists. The language requirement removed the opportunity for linguistically diverse populations to participate and be represented in clinical trials.

Future physiotherapy trials could minimise the exclusion of people lacking in language proficiency by implementing strategies to address potential language barriers. Good examples include recruiting interpreters or multilingual staff or providing validated questionnaires in other languages. Understanding these issues and developing targeted strategies are of great significance when planning for the delivery of physiotherapy services to culturally and linguistically diverse communities.

Chen Q, Sánchez Medina CM, Maher CG, et al. Almost one in five physiotherapy trials excluded people due to lack of language proficiency: A meta-epidemiological study. J Clin Epidemiol. 2022;152:13-22. doi:10.1016/j.jclinepi.2022.09.007

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