Long-term effectiveness and cost-effectiveness of cognitive behavioural therapy as an adjunct to pharmacotherapy for treatment-resistant depression in primary care: follow-up of the CoBalT randomised controlled trial

Wiles, N. J. et al. (2016) Long-term effectiveness and cost-effectiveness of cognitive behavioural therapy as an adjunct to pharmacotherapy for treatment-resistant depression in primary care: follow-up of the CoBalT randomised controlled trial. Lancet Psychiatry, 3(2), pp. 137-144. (doi: 10.1016/S2215-0366(15)00495-2) (PMID:26777773)

Abstract

Background: Cognitive behavioural therapy (CBT) is an effective treatment for people whose depression has not responded to antidepressants. However, the long-term outcome is unknown. In a long-term follow-up of the CoBalT trial, we examined the clinical and cost-effectiveness of cognitive behavioural therapy as an adjunct to usual care that included medication over 3–5 years in primary care patients with treatment-resistant depression. Methods: CoBalT was a randomised controlled trial done across 73 general practices in three UK centres. CoBalT recruited patients aged 18–75 years who had adhered to antidepressants for at least 6 weeks and had substantial depressive symptoms (Beck Depression Inventory [BDI-II] score ≥14 and met ICD-10 depression criteria). Participants were randomly assigned using a computer generated code, to receive either usual care or CBT in addition to usual care. Patients eligible for the long-term follow-up were those who had not withdrawn by the 12 month follow-up and had given their consent to being re-contacted. Those willing to participate were asked to return the postal questionnaire to the research team. One postal reminder was sent and non-responders were contacted by telephone to complete a brief questionnaire. Data were also collected from general practitioner notes. Follow-up took place at a variable interval after randomisation (3–5 years). The primary outcome was self-report of depressive symptoms assessed by BDI-II score (range 0–63), analysed by intention to treat. Cost-utility analysis compared health and social care costs with quality-adjusted life-years (QALYs). This study is registered with isrctn.com, number ISRCTN38231611. Findings: Between Nov 4, 2008, and Sept 30, 2010, 469 eligible participants were randomised into the CoBalT study. Of these, 248 individuals completed a long-term follow-up questionnaire and provided data for the primary outcome (136 in the intervention group vs 112 in the usual care group). At follow-up (median 45·5 months [IQR 42·5–51·1]), the intervention group had a mean BDI-II score of 19·2 (SD 13·8) compared with a mean BDI-II score of 23·4 (SD 13·2) for the usual care group (repeated measures analysis over the 46 months: difference in means −4·7 [95% CI −6·4 to −3·0, p<0·001]). Follow-up was, on average, 40 months after therapy ended. The average annual cost of trial CBT per participant was £343 (SD 129). The incremental cost-effectiveness ratio was £5374 per QALY gain. This represented a 92% probability of being cost effective at the National Institute for Health and Care Excellence QALY threshold of £20 000. Interpretation: CBT as an adjunct to usual care that includes antidepressants is clinically effective and cost effective over the long-term for individuals whose depression has not responded to pharmacotherapy. In view of this robust evidence of long-term effectiveness and the fact that the intervention represented good value-for-money, clinicians should discuss referral for CBT with all those for whom antidepressants are not effective.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Williams, Professor Christopher and Morrison, Professor Jill
• Authors: Wiles, N. J., Thomas, L., Turner, N., Garfield, K., Kounali, D., Campbell, J., Kessler, D., Kuyken, W., Lewis, G., Morrison, J., Williams, C., Peters, T. J., and Hollinghurst, S.
• College/School: College of Medical Veterinary and Life Sciences > School of Health & Wellbeing > General Practice and Primary Care; College of Medical Veterinary and Life Sciences > School of Health & Wellbeing > Mental Health and Wellbeing
• Journal Name: Lancet Psychiatry
• Publisher: Elsevier B.V.
• ISSN: 2215-0366
• ISSN (Online): 2215-0374
• Published Online: 06 January 2016
• Copyright Holders: Copyright © 2016 Wiles et al
• First Published: First published in Lancet Psychiatry 3(2):137-144
• Publisher Policy: Reproduced under a Creative Commons License