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Bottom line
Digital CBT for insomnia was well received by people with comorbid insomnia and low back pain and online data collection worked well, but recruitment, follow-up, and adherence fell short of targets, so a larger trial needs design changes before efficacy can be judged.
Preliminary evidencePublished
Evidence hierarchy
Study participants
Adults with comorbid symptoms of insomnia and low back pain of at least 6 weeks duration, recruited from an Australian twin registry and the general community
Study Summary
This feasibility randomized controlled trial tested whether a study of digital cognitive behavioral therapy for insomnia (CBT-i, delivered via the Sleepio app) was practical to run in people who had both insomnia symptoms and low back pain, using a twin-control design plus a singleton (general community) cohort. Across 32 twins (16 pairs) and 66 singletons randomized to either six weeks of digital CBT-i or a six-email sleep-education control, the authors measured recruitment, follow-up, data completion, adherence, contamination, and intervention credibility rather than clinical efficacy outcomes. Feasibility targets were met for online data collection and (in twins) contamination of intervention, but were not met for twin recruitment (2.2%), follow-up rates (72-82%), or adherence (55-63% completing at least four of six sessions). Participants generally viewed the digital CBT-i favorably, but the educational control was judged poorly credible, and the authors conclude the full trial is not feasible in its current form without design changes.
Key Findings
| Finding | Detail | Impact |
|---|---|---|
| Twin recruitment fell far short of the feasibility target | Of 722 twin pairs contacted by the twin registry, 16 pairs were recruited (recruitment rate 2.2%), well below the pre-specified target of at least 10% contacted being recruited. However, of the 17 eligible pairs, 16 (94.1%) consented, meeting the separate target of recruiting at least 70% of eligible pairs. | High |
| Follow-up rates did not meet the feasibility threshold | Post-intervention and 3-month follow-up rates were 81% and 72% for twins and 82% and 78% for singletons, all below the pre-specified target of at least 85%. | High |
| Adherence to digital CBT-i was below target | Ten of 16 twins (63%) and 18 of 33 singletons (55%) completed at least four of the six sessions, below the at-least-75% adherence criterion. These rates were also lower than prior Sleepio trials in insomnia-only populations (58-85%). | High |
| Online data collection was feasible | Total missing values were 13% for both twins and singletons, meeting the at-most-20% criterion. Twins interviewed found the online questionnaires easy to understand, relevant, and acceptable in length. | Medium |
| Contamination among twins stayed within the acceptable limit | From questionnaires, 13% reported talking to their twin about the intervention and 6% reported being aware of their co-twin's allocation (below the at-most-15% criterion); none reported changing behavior as a result. | Medium |
| The educational control group lacked credibility | Intervention Credibility Scale scores (0-24) for the control were below 12 in both twins (mean 10.69, SD 3.43) and singletons (mean 8.75, SD 4.71), and were higher in the CBT-i group (mean difference 4.61, 95% CI 1.76-7.46 for twins; 4.62, 95% CI 1.94-7.31 for singletons). Most participants could correctly guess their allocation, indicating blinding was not maintained. | Medium |
| Participant experience with digital CBT-i was generally positive | Of 21 comments about the digital CBT-i, 11 were positive, 5 neutral, and 6 negative; positive comments mainly cited improvements in sleep (n=5), pain (n=1), and the program's interactivity (n=2). By contrast, control-group feedback was largely negative (14 of 22 comments). | Medium |
Of 722 twin pairs contacted by the twin registry, 16 pairs were recruited (recruitment rate 2.2%), well below the pre-specified target of at least 10% contacted being recruited. However, of the 17 eligible pairs, 16 (94.1%) consented, meeting the separate target of recruiting at least 70% of eligible pairs.
Post-intervention and 3-month follow-up rates were 81% and 72% for twins and 82% and 78% for singletons, all below the pre-specified target of at least 85%.
Ten of 16 twins (63%) and 18 of 33 singletons (55%) completed at least four of the six sessions, below the at-least-75% adherence criterion. These rates were also lower than prior Sleepio trials in insomnia-only populations (58-85%).
Total missing values were 13% for both twins and singletons, meeting the at-most-20% criterion. Twins interviewed found the online questionnaires easy to understand, relevant, and acceptable in length.
From questionnaires, 13% reported talking to their twin about the intervention and 6% reported being aware of their co-twin's allocation (below the at-most-15% criterion); none reported changing behavior as a result.
Intervention Credibility Scale scores (0-24) for the control were below 12 in both twins (mean 10.69, SD 3.43) and singletons (mean 8.75, SD 4.71), and were higher in the CBT-i group (mean difference 4.61, 95% CI 1.76-7.46 for twins; 4.62, 95% CI 1.94-7.31 for singletons). Most participants could correctly guess their allocation, indicating blinding was not maintained.
Of 21 comments about the digital CBT-i, 11 were positive, 5 neutral, and 6 negative; positive comments mainly cited improvements in sleep (n=5), pain (n=1), and the program's interactivity (n=2). By contrast, control-group feedback was largely negative (14 of 22 comments).
Strengths
- Randomized controlled design with concealed allocation, blinded outcome assessment, blinded analysis, and intention-to-treat analysis
- Protocol published in advance and reporting followed CONSORT and TIDieR checklists
- Included both twin and singleton cohorts, allowing comparison of recruitment and feasibility between the two designs
- Online electronic surveys allowed more cost-effective and accurate measurement of adherence, credibility, and outcomes than handwritten surveys
Limitations
- This was a feasibility study, not powered or designed to establish clinical efficacy on sleep or pain outcomes
- Small sample (16 twin pairs, 66 singletons), with only one dizygotic twin pair
- Participants were recruited by phone or online and may be more interested in addressing insomnia and more comfortable with digital platforms than the wider population
- Other sleep disorders were not ruled out via polysomnography due to cost
- Adherence reasons were not collected, and it was unknown what proportion of control participants actually read the educational emails
- The control intervention (sleep-education emails) lacked credibility and blinding was not maintained, which may have lowered follow-up
- The multi-component nature of Sleepio meant the contribution of individual components could not be determined
Key Takeaways for Patients
What This Means for You
- 01Insomnia and low back pain often occur together, and treating poor sleep may help both, since the link between sleep and pain appears to run in both directions.
- 02Cognitive behavioral therapy for insomnia (CBT-i) is the recommended first-line treatment for insomnia, and an online version (the Sleepio app) makes it more accessible than face-to-face therapy.
- 03In this study, people with both insomnia and back pain generally liked the online CBT-i program, with several reporting better sleep, but only about half to two-thirds completed at least four of the six sessions.
- 04Some participants wanted the program to address their back pain directly, not just sleep, which may be one reason engagement was lower than in studies of people with insomnia alone.
- 05This was a feasibility study designed to test whether a larger trial can run smoothly, not to prove that the app reduces pain or improves sleep, so it does not establish how well digital CBT-i works for this group.
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