This chapter uses material from an Open Access article previously published by the research team (see Kyle et al. 20201). This article is published under licence to BMJ. This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 4.0) licence, which permits others to distribute, remix, adapt and build upon this work, for commercial use, provided the original work is properly cited. See: https://creativecommons.org/licenses/by/4.0/.
Insomnia disorder is characterised by persistent problems with sleep initiation and/or maintenance, which leads to impairment in daytime functioning and quality of life.2–4 Insomnia affects approximately 10% of the adult population4 and is a risk factor for several mental and physical health problems, particularly depression and cardiometabolic disease.5,6 Insomnia is also an expensive condition, associated with substantial direct and indirect costs, chiefly reflecting increased healthcare utilisation, work-related absenteeism, reduced work productivity and elevated accident risk.7–9
Insomnia is treatable. Clinical guidelines10–13 recommend multicomponent cognitive–behavioural therapy (CBT) as the first-line treatment, but access remains extremely limited, particularly in primary care where insomnia is principally managed. Studies in multiple countries show that general practitioners (GPs) almost never offer CBT as a treatment for insomnia, either directly or via referral.14,15 For example, in a study of primary care patients in Switzerland, just 1% of patients diagnosed with insomnia disorder received CBT.16 Instead, patients are typically prescribed hypnotics (which are indicated for short-term use, and only if CBT is not available or ineffective), off-label sedative antidepressant medication, or self-help sleep hygiene (SH) advice. None of these treatment approaches are recommended or evidence-based for the treatment of chronic insomnia. GPs are frustrated by this situation. Barriers to wide-scale adoption of CBT in routine health care relate to limited training, expertise and funding. A major development in the insomnia field, therefore, has been the dismantling of multicomponent, multisession CBT into brief and focused treatment packages17 and the training of non-specialists to deliver such therapies.18–22
Sleep restriction therapy (SRT) has emerged as one of the primary active components within multicomponent CBT. The therapy involves restricting and standardising a patient’s time in bed with the aim of increasing homeostatic sleep pressure, over-riding cognitive and physiological arousal and strengthening circadian regulation of sleep.23–26 Tailored prescription of bed and rise times over several weeks leads to improved sleep consolidation and reduction in insomnia severity. We recently performed a meta-analysis of randomised trials (8 studies; 533 participants) comparing SRT to control and found medium-to-large effects on sleep continuity measures and large effects for reduction in insomnia severity (Hedges’ g = -0.93) at post treatment.27
Trials were predominantly performed within specialist research settings, recruiting small samples from the community who were typically free from comorbidity and did not use hypnotic medication. One trial was performed in primary care and tested GP delivery of brief SRT relative to a SH control, and showed encouraging results on the Insomnia Severity Index (ISI) at 6 months follow-up.28 Our view was that a pragmatic trial in primary care testing a scalable model of treatment delivery was required.
We developed a brief SRT protocol based on (1) our extensive research using multicomponent CBT18–20 and (2) systematic examination of the patient experience of SRT.29 We aimed to test whether brief SRT (alongside SH advice) was both clinically and cost-effective, relative to SH advice on its own. We chose practice nurses (PNs) as sleep therapists because nurses are increasingly involved in supporting lifestyle change and self-management of chronic conditions in primary care, and with scalability and cost-effectiveness in mind.30 While previous studies in UK primary care showed multicomponent CBT to be effective when delivered by nurses,18,19 counsellors31 or through self-help CBT booklets,32 there had been no large-scale evaluation of the clinical and cost-effectiveness of a brief and scalable behavioural intervention.33
Objectives
The primary objective of the Health-professional Administered Brief Insomnia Therapy (HABIT) trial was to establish whether nurse-delivered SRT for insomnia disorder in primary care improves insomnia more than SH. We hypothesised that participants allocated to SRT would demonstrate lower insomnia severity at 6 months post randomisation compared with those allocated to SH.
Our secondary hypotheses were as follows:
- Compared with SH, participants allocated to SRT would report improvements in health-related quality of life (HRQoL), sleep-related quality of life, depressive symptoms, work productivity, pre-sleep arousal and sleep effort (at 3, 6, and 12 months).
- Compared with SH, participants allocated to SRT would demonstrate improvements in sleep parameters (diary and actigraphy-recorded) and report a reduction in use of sleep-promoting medication (6 and 12 months).
- The effect of SRT on insomnia severity would be mediated via reduction in sleep effort and pre-sleep arousal.
Other objectives:
- To establish whether nurse-delivered SRT for insomnia disorder in primary care is cost-effective compared with SH, from a NHS Personal Social Services (PSS) perspective, and from a societal perspective.
- To undertake a process evaluation to understand intervention delivery, fidelity and acceptability.
- To test whether insomnia phenotype moderates clinical benefit obtained from SRT. One prominent model posits that participants with objective short sleep duration are less likely to experience improvement in insomnia relative to those with normal sleep duration.5 We will examine whether actigraphy-defined sleep duration (< 6 vs. ≥ 6 hours) at baseline moderates the effect of SRT on clinical outcomes (at 6 months).
- To test whether SRT adherence is associated with degree of clinical change (ISI) from baseline to 3 months, and from baseline to 6 months.