Cost effectiveness of therapist delivered cognitive behavioural therapy and web-based self-management in irritable bowel syndrome: the ACTIB randomised trial

Background: Telephone therapist delivered CBT (TCBT) and web-based CBT (WCBT) have been shown to be significantly more clinically effective than treatment as usual (TAU) at reducing IBS symptom severity and impact at 12 months in adults with refractory IBS. In this paper we assess the cost-effectiveness of the interventions. Methods: Participants were recruited from 74 general practices and three gastroenterology centres in England. Interventions costs were calculated, and other service use and lost employment measured and costed for one-year post randomisation. Quality-adjusted life years (QALYs) were combined with costs to determine cost-effectiveness of TCBT and WCBT compared to TAU. Results: TCBT cost £956 more than TAU (95% CI, £601-£1435) and generated 0.0429 more QALYs. WCBT cost £224 more than TAU (95% CI, - £11 to £448) and produced 0.029 more QALYs. Compared to TAU, TCBT had an incremental cost per QALY of £22,284 while the figure for WCBT was £7724. After multiple imputation these ratios increased to £27,436 and £17,388 respectively. Including lost employment and informal care, TCBT had costs that were on average £866 lower than TAU (95% CI, - £1133 to £2957), and WCBT had costs that were £1028 lower than TAU (95% CI, - £448 to £2580). Conclusions: TCBT and WCBT resulted in more QALYs and higher costs than TAU. Complete case analysis suggests both therapies are cost-effective from a healthcare perspective. Imputation for missing data reduces cost-effectiveness but WCTB remained cost-effective. If the reduced societal costs are included both interventions are likely to be more cost-effective. Trial registration ISRCTN44427879 (registered 18.11.13)