Can you start by briefly summarising the design and findings of the BOOST study? 

The Better Outcomes for Older people with Spinal Trouble (BOOST) study was a randomised controlled trial testing a multicomponent physical and psychological intervention for older adults with neurogenic claudication due to lumbar spinal stenosis in comparison to best practice advice. 

Four hundred and thirty-five participants were randomised 2:1 to either the BOOST or the control group. 

At 12 months, there was no significant difference in Oswestry Disability Index scores between groups but at six months, Oswestry Disability Index scores favoured the BOOST intervention. 

However, the walking component of the Oswestry Disability Index and the six-minute walk test demonstrated a statistically significant difference in favour of the BOOST intervention at 12 months. 

What motivated you to conduct a mediation analysis of the BOOST trial and how did you decide which potential mediators to examine? 

Dr Christine Comer designed the mediation analysis with the BOOST team, which had undertaken extensive intervention development. 

Walking capacity was selected as the primary mediator because walking limitation is often the key driver for people with neurogenic claudication. 

However, self-efficacy has also been shown to play a role in mediating disability, physical function and activity in older adults with chronic musculoskeletal conditions and therefore we included walking self-efficacy. 

Little is known about how exercise affects neurogenic claudication symptom severity and our team hypothesised that symptom severity would improve with better physical conditioning. 

Your analysis found that walking confidence and pain reduction—not walking capacity—were the key drivers of improved walking disability. Were you surprised by this? 

Yes, we were. 

We anticipated that walking capacity would be the key mechanism that would underpin the changes in other mediators but it appears this was not the case. 

What is interesting is that it was the combination of effects accounting for the greatest change. 

What practical changes would you recommend physiotherapists make based on your findings— particularly in time-limited clinical settings? 

Don’t underestimate the importance of supervised walking as an exercise. 

The BOOST intervention included time for participants to practise their walking and to build their confidence with the support and supervision of the physio. 

This was tailored to the individual’s ability and included adding challenges like walking faster, going up and down stairs, stepping over floor ladders, changing direction or walking on uneven ground. 

How do you suggest clinicians assess walking confidence and pain severity in routine practice? Are there quick and feasible tools you’d recommend? 

We used one question from the Gait Efficacy Scale—‘How much confidence do you have that you would be able to safely walk a long distance such as 1/2 mile?’ 

Clinicians could incorporate this question easily into their clinical assessment, alongside an assessment of pain severity. 

The BOOST program includes psychological components. Do you think these are underused in current physiotherapy practice for older adults with neurogenic claudication? 

Yes, we often underestimate the importance of individualised, person-centred care and the importance of motivational interviewing techniques and personalised goals. 

Using these methods to underpin how we engage with our patients is often underused, not just in older adults with neurogenic claudication. 

Given that walking capacity was not a key mediator, should we rethink how we measure success in physiotherapy for this population? 

No. Although walking capacity was not a key mediator, all mediators were important contributors to explaining the overall effect of walking ability. 

Our determination of success (walking ability) can be the same irrespective. 

What are your next steps? Are you planning further research to refine the intervention, explore implementation or test other patient groups? 

The team was fortunate to get some funding to undertake optimisation of the program to see if they could improve its effects and make it easy to implement. 

Dr Esther Williamson and Professor Sallie Lamb have been leading this work. The BOOST training program is freely available for clinicians to use and apply to their settings. Click here to access the resources. 

>>>Dr Lianne Wood is a clinical academic advanced practice spinal physiotherapist and a senior research fellow at the University of Exeter, UK. 

>>>Dr Esther Williamson is a senior researcher at the University of Exeter and University of Oxford. Since 2004, she has been working on randomised controlled trials evaluating rehabilitation for musculoskeletal conditions including the BOOST trial.