The modifying role of baseline pain intensity and duration on the effect of app-delivered self-management for low back pain: secondary analyses of the selfBACK trial

Research Aim/Objective:
The artificial intelligence-based SELFBACK app supports tailored self-management of non-specific low
back pain (LBP) and have been shown to reduce LBP-related disability. In this secondary analysis of the
SELFBACK randomized controlled trial, we explore if intensity and duration of LBP at baseline modify the
effect of the SELFBACK intervention.
Research Methods:
461 adults seeking care for LBP in primary care or an outpatient spine clinic were randomized to the
SELFBACK intervention adjunct to usual care (n=232) or usual care alone (n=229). We classified
participants based on baseline score of pain intensity the last week (≤5 points or >5 points) measured by
the 0-10 Numeric rating scale (NRS) and duration of the current LBP episode (≤12 weeks or >12 weeks).
Outcomes were LBP-related disability measured by the Roland Morris Disability Questionnaire (RMDQ),
average LBP intensity, pain self-efficacy, and global perceived effect. Outcomes were measured at
baseline, 6 weeks, 3, 6 and 9 months. We compared the mean difference between SELFBACK and usual
care, stratified by baseline level of LBP intensity and duration of the current LBP episode.
Results:
461 adults seeking care for LBP in primary care or an outpatient spine clinic were randomized to the
SELFBACK intervention adjunct to usual care (n=232) or usual care alone (n=229). We classified
participants based on baseline score of pain intensity the last week (≤5 points or >5 points) measured by
the 0-10 Numeric rating scale (NRS) and duration of the current LBP episode (≤12 weeks or >12 weeks).
Outcomes were LBP-related disability measured by the Roland Morris Disability Questionnaire (RMDQ),
average LBP intensity, pain self-efficacy, and global perceived effect. Outcomes were measured at
baseline, 6 weeks, 3, 6 and 9 months. We compared the mean difference between SELFBACK and usual
care, stratified by baseline level of LBP intensity and duration of the current LBP episode.
Discussion:
Although we observed an overall small favourable effect of SELFBACK for participants with the highest
level of symptoms, there was no clear evidence of differences in the effect of a tailored app-delivered
self-management intervention in subgroups defined according to baseline level of pain intensity or pain
duration. Thus, our findings indicate that clinicians should not refrain from advising individually tailored
self-management support for patients with high LBP and persistent symptoms; however, this requires
further research.