Background

Depression is a common and disabling condition that is often treated with antidepressant medication in UK primary care. There is interest in non-pharmacological treatments for depression. Currently, counselling and cognitive behavioural therapy are used, although access is often limited.

There is increasing interest in the possibility that physical activity could lead to an improvement in symptomatic outcome in people with depression. An existing systematic review has indicated that, on average, there is a large treatment effect in the existing randomised trials of physical activity in depression. However, there are some limitations in the methodology used and many of the studies are small and have recruited from non-clinical populations.

If physical activity is to be a useful intervention, it is also important to consider the nature of the intervention to be used. Many of the previous studies have not developed a pragmatic intervention that could be used in primary care. We chose to develop a new physical activity intervention delivered by a physical activity facilitator (PAF). The principles behind the intervention were to provide choice and encourage autonomy in order to incorporate the physical activity as a routine part of the participant’s life and to help to sustain any increase in physical activity beyond the duration of the intervention.

The TREAting Depression with physical activity (TREAD) study was designed to address a pragmatic question concerned with the effectiveness of our physical activity intervention as a treatment for depression. We wished to examine the intervention as an adjunct to usual care that could include antidepressant medication or a psychological treatment. We intended that our physical activity intervention would be less costly and time-consuming than other psychotherapies such as cognitive behavioural therapy.

Objective

The overall objective of the project was to evaluate the cost-effectiveness of a physical activity intervention as an addition to usual care as a treatment for depression. The first step was to develop a physical activity intervention designed to increase physical activity levels in people with depression. We then conducted a randomised controlled trial in which the physical activity intervention in addition to usual care was compared with usual care alone. We included a nested qualitative study to explore patients’ and general practitioners’ (GPs’)expectations and experiences of physical activity and the physical activity intervention, with the particular aims of understanding:

• participants’ and GPs’ beliefs and attitudes to physical activity as a treatment for depression
• the acceptability and experience of the physical activity intervention
• how being in the usual care arm affected behaviour.

Methods

We carried out an individually randomised, multicentre trial in which we compared physical activity in addition to usual care with usual care. The randomisation ratio was 1 : 1. The randomisation was carried out with a remote automated telephone system and was stratified by antidepressant use and minimised by centre, severity of symptoms and level of physical activity at baseline.

Participants were recruited from primary care in the Bristol and Exeter areas either by referral from GPs or by identifying likely individuals from the practice database and then inviting them with a letter sent by the GP.

The inclusion criteria were age 18–69 years, with a diagnosis of depression according to the International Classification of Diseases and Related Health Problems, 10th Edition (ICD-10), a score of ≥ 14 on the Beck Depression Inventory (BDI), not taking antidepressants at the time of assessment or had been prescribed antidepressants within 4 weeks of assessment but had had an antidepressant-free period of 4 weeks prior to that, able to complete self-administered questionnaires in English and no medical contraindications to physical activity. Exclusions were psychosis, bipolar disorder, serious substance abuse and if pregnant or breastfeeding.

The primary outcome was the BDI at 4 months post randomisation and further follow-ups were conducted at 8 and 12 months. Secondary outcomes included use of antidepressants, level of physical activity and quality of life. Resource-use data were collected from GP records and by self-report at the follow-up points.

A subset of participants was asked to wear an accelerometer after the 4-month follow-up point in order to compare the results of an objective measure of activity with the self-reported information they provided.

Some participants were also asked to contribute to in-depth interviews that were transcribed so that themes could be identified and then coded and analysed using the framework method.

The physical activity intervention was designed to encourage autonomy and provide choice for the participants. A trained PAF met the participants on up to three occasions for face-to-face sessions and had telephone contact for up to a further 10 sessions. The intervention was designed to last about 6–8 months. A written manual was prepared for the PAFs.

Results

Sixty-five practices agreed to take part in the study and baseline assessments were performed on 490 subjects; a total of 361 participants were randomised from the 65 practices with 80% follow-up at 4 months, 61% at 8 months and 71% at 12 months.

At baseline, 182 were randomised to the intervention and 179 to the usual care arm. The two randomised groups were very comparable at baseline. Adherence to the physical activity intervention was good: > 95% attended at least one session, whereas about 70% received at least five sessions including a face-to-face meeting.

The primary analysis indicated that there was no evidence that the intervention group had a better outcome than the usual care group, although the intervention arm did score very slightly lower on the BDI [–0.54, 95% confidence interval (CI) –3.06 to 1.99]. We also examined whether or not there was any evidence of clinical benefit over the duration of the study using a repeated measures linear regression and this had the same conclusion (BDI score –1.20, 95% CI –3.4 to 1.02). There was no evidence that the intervention influenced the use or prescription of antidepressants or quality of life measures.

There was evidence that the physical activity intervention led to an increase in physical activity in the participants. Repeated measures analysis results (odds ratio for a higher level of physical activity 2.27, 95% CI 1.32 to 3.89, p = 0.003) indicated that the increase in physical activity was present at all follow-up points and there was evidence that the increase in physical activity was still present at 12 months post randomisation, after the intervention had ended in the majority of participants. There was also evidence that the intervention led to a change in expectations of physical activity.

There was a correlation between the accelerometer results and the self-reported physical activity recall diary used in the study. However, there were also marked differences in rates of light physical activity, probably resulting from the different criteria used by the two methods.

The qualitative interviews with patients indicated that the intervention was seen as highly acceptable and encouraging of physical activity. Some participants attributed improvement to an increase in physical activity but also reported that other factors had been important as well.

On average the intervention cost approximately £220 per person. The costs incurred by the intervention group were greater than those receiving usual care mostly because of the cost of the intervention. As a result, it is very unlikely that the intervention is cost-effective at current willingness-to-pay thresholds.

Conclusions

Trial registration

This trial is registered as ISRCTN16900744.

Funding

Funding for this study was provided by the Health Technology Assessment programme of the National Institute for Health Research.

Publication

• Chalder M, Wiles NJ, Campbell J, Hollinghurst SP, Searle A, Haase AM, et al. A pragmatic randomised controlled trial to evaluate the cost-effectiveness of a physical activity intervention as a treatment for depression: the treating depression with physical activity (TREAD) trial. Health Technol Assess 2012;16(10). [PubMed: 22398106]

NIHR Health Technology Assessment programme

The Health Technology Assessment (HTA) programme, part of the National Institute for Health Research (NIHR), was set up in 1993. It produces high-quality research information on the effectiveness, costs and broader impact of health technologies for those who use, manage and provide care in the NHS. ‘Health technologies’ are broadly defined as all interventions used to promote health, prevent and treat disease, and improve rehabilitation and long-term care.

The research findings from the HTA programme directly influence decision-making bodies such as the National Institute for Health and Clinical Excellence (NICE) and the National Screening Committee (NSC). HTA findings also help to improve the quality of clinical practice in the NHS indirectly in that they form a key component of the ‘National Knowledge Service’.

The HTA programme is needs led in that it fills gaps in the evidence needed by the NHS. There are three routes to the start of projects.

First is the commissioned route. Suggestions for research are actively sought from people working in the NHS, from the public and consumer groups and from professional bodies such as royal colleges and NHS trusts. These suggestions are carefully prioritised by panels of independent experts (including NHS service users). The HTA programme then commissions the research by competitive tender.

Second, the HTA programme provides grants for clinical trials for researchers who identify research questions. These are assessed for importance to patients and the NHS, and scientific rigour.

Third, through its Technology Assessment Report (TAR) call-off contract, the HTA programme commissions bespoke reports, principally for NICE, but also for other policy-makers. TARs bring together evidence on the value of specific technologies.

Some HTA research projects, including TARs, may take only months, others need several years. They can cost from as little as £40,000 to over £1 million, and may involve synthesising existing evidence, undertaking a trial, or other research collecting new data to answer a research problem.

The final reports from HTA projects are peer reviewed by a number of independent expert referees before publication in the widely read journal series Health Technology Assessment.

Criteria for inclusion in the HTA journal series

Reports are published in the HTA journal series if (1) they have resulted from work for the HTA programme, and (2) they are of a sufficiently high scientific quality as assessed by the referees and editors.

Reviews in Health Technology Assessment are termed ‘systematic’ when the account of the search, appraisal and synthesis methods (to minimise biases and random errors) would, in theory, permit the replication of the review by others.

The research reported in this issue of the journal was commissioned by the HTA programme as project number 03/45/07. The contractual start date was in August 2006. The draft report began editorial review in October 2011 and was accepted for publication in October 2011. As the funder, by devising a commissioning brief, the HTA programme specified the research question and study design.The authors have been wholly responsible for all data collection, analysis and interpretation, and for writing up their work. The HTA editors and publisher have tried to ensure the accuracy of the authors’ report and would like to thank the referees for their constructive comments on the draft document. However, they do not accept liability for damages or losses arising from material published in this report.

The views expressed in this publication are those of the authors and not necessarily those of the HTA programme or the Department of Health.

Editor-in-Chief: Professor Tom Walley CBE

Series Editors: Dr Martin Ashton-Key, Professor Aileen Clarke, Dr Tom Marshall, Professor John Powell, Dr Rob Riemsma and Professor Ken Stein

Associate Editor: Dr Peter Davidson