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Low back pain is the leading cause of disability worldwide and Australia is no exception. Around 4 million Australians live with back pain and it is one of the most common reasons people see their GP or physiotherapist. The personal toll from chronic low back pain is significant and so too is the system impact with billions spent each year on health care and lost through reduced workplace productivity or early retirement.
Current care for chronic low back pain is inadequate, with many patient’s not receiving evidence-based treatments. As a result, patient outcomes remain suboptimal, and many people cycle through multiple interventions that offer only modest or temporary improvements at best. Part of this problem is that chronic low back pain is influenced by multiple biological, psychological and social factors which aren’t commonly addressed in available treatments. This complexity has led to a growing interest in more comprehensive, multi-modal or multi-disciplinary care which better targets potential contributors. Identifying which people are likely to benefit more from this care is crucial to move towards more personalised or precision rehabilitation, which refers to matching treatments to the people most likely to benefit from them.
One promising treatment approach for chronic low back pain that may lead to meaningful long-term benefits is graded sensorimotor retraining. This contemporary rehabilitation program is designed to target the many factors contributing to chronic low back pain including understanding and beliefs, body perception, motor control and pain related fear. Graded sensorimotor retraining incorporates pain science education, pre-movement tasks (ie, tactile precision practice and graded motor imagery) and graded movement and loading. An unanswered question about this intervention was who this approach is most helpful for. Understanding who benefits (or doesn’t benefit) from an intervention is important information to support intervention translation from research to practice.
What we did
To explore this question, we conducted a secondary analysis of data from the RESOLVE randomised controlled trial of 276 participants which investigated graded sensorimotor retraining compared to an attention and sham control for people with chronic low back pain. The original RESOLVE trial found that graded sensorimotor retraining demonstrated clinically meaningful and sustained improvements in pain and disability. In the current study, we examined whether specific theory-informed patient characteristics measured at baseline influenced the effect of the intervention to identify for whom the treatment was most beneficial. In the field of precision medicine, these patient characteristics are called treatment effect modifiers or moderators.
We investigated a range of factors that clinicians commonly identify or assess in practice, including pain intensity, disability level, beliefs about back pain, pain self-efficacy, movement-related fear, pain catastrophising, back perception and psychoactive medication use. We followed best-practice methods to investigate whether these features, measured prior to treatment, changed the size of the treatment effect.
What we found
We did not find any strong effect modifiers; the treatment appeared to work reasonably consistently across most subgroups assessed in this study. In other words, the benefits received from graded sensorimotor retraining was not limited to a specific type of patient characteristic considered. We did find preliminary evidence that levels of back perception (eg, how accurately a person feels, senses and mentally represents their back) may be a potential effect modifier of graded sensorimotor retraining, with people with lower levels of disrupted back perceptions, benefitting more from the intervention at the long-term follow-up (52 weeks). Back perception could be measured using the Fremantle Back Awareness Questionnaire to help guide treatment decisions, however future confirmatory research is required. We did not find strong evidence that simple clinical variables such as pain intensity, disability levels or psychoactive medication use meaningfully changed treatment response, which challenges some common assumptions.
The strengths in this work lie in its use of data from a high quality, randomized trial with limited missing data. There are also important limitations. This was a secondary analysis, meaning it was not originally designed to detect subgroup effects. This is a common issue in the field of precision medicine. Findings should therefore be seen as hypothesis generating rather than definitive. Additionally, effect modifiers were tested individually, whereas in real life, patients present with combinations of features that may interact in complex ways. This study focussed on investigating clinical variables as treatment effect modifiers but there may be other important demographic variables including social determinants on health (eg, age, education level or ethnicity) that require further investigation.
In short, the study suggests that graded sensorimotor retraining has broad potential value as a treatment option for people with chronic low back pain.
Where to from here
This study provides evidence to guide the implementation of graded sensorimotor retraining into clinical practice. While we cannot yet clearly identify which patients are most likely to benefit (ie, there were no strong effect modifiers), this finding also suggests the intervention may have relevance across a broad range of people with chronic low back pain rather than being limited to a narrow subgroup from our investigated characteristics.
The next stage for graded sensorimotor retraining involves translating the intervention from the original research trial into a treatment appropriate and acceptable for real-word physiotherapy practice. Like many interventions tested in clinical trials, the original program was delivered under structured conditions that may not perfectly reflect the realities of a busy primary care setting. We have completed work adapting the intervention to better fit routine physiotherapy practice, before widespread implementation. The optimised intervention is currently being investigated in a large, pragmatic, Australian Government funded clinical trial conducted across Australia within physiotherapy practices. This will allow us to evaluate not only the intervention’s effectiveness in real-world settings but also its readiness for broader clinical implementation.
Chronic low back pain remains a major challenge for clinicians and health systems alike. Bridging the gap between promising research interventions and treatments that can be delivered in everyday practice is an essential step toward improving care.
Martjie Venter is a doctoral candidate at the Centre for Pain IMPACT, Neuroscience Research Australia and the School of Health Sciences, University of New South Wales. Her research focusses on the translation of evidence-based interventions for chronic low back pain from research to practice.
Dr Aidan Cashin is a Senior Research Scientist at the Centre for Pain IMPACT, Neuroscience Research Australia and a UNSW Scientia Fellow in the School of Population Health, University of New South Wales.
The statements or opinions expressed in this article reflect the views of the authors and do not necessarily represent the official policy of the AMA, the MJA or InSight+ unless so stated.
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