Background: There is a growing interest in using group
cognitive–behavioral therapy (CBT) with people who have Asperger syndrome (AS)
and comorbid mental health problems. This study aims to assess the
cost-effectiveness of modified group CBT for adults with AS experiencing
co-occurring anxiety compared to treatment-as-usual. Methods:
Economic evaluation alongside a pilot, multicenter, single-blind, randomized
controlled crossover trial. Costs from the UK public sector (National Health
Service and Social Services) and societal perspectives, quality-adjusted life
years (QALYs), incremental net (monetary) benefit (INB), expected value of
perfect information, expected value of sample information, expected net gain of
sampling, and efficient sample size of a future trial are reported.
Results: Over 48 weeks, from the societal perspective, CBT
results in additional costs of £6,647, with only a 0.015 incremental gain in
QALYs, leading to a negative INB estimate of £6,206 and a 23% probability of
cost-effectiveness at a threshold of £30,000/QALY. Results from sensitivity
analyses support the unlikely cost-effectiveness of CBT but indicate the
potential for cost-effectiveness over longer time horizons. Eliminating decision
uncertainty is valued at £277 million, and the efficient sample size for a
future trial is estimated at 1,200 participants per arm.
Limitations: Relatively small sample size and prevalence of
missing data present challenges to the interpretation of the results.
Conclusions: Current evidence from this small pilot study
suggests that, on average, modified group CBT is not cost-effective. However,
there is much decision uncertainty so such a conclusion could be wrong. A large,
full-scale trial to reduce uncertainty would be an efficient investment for the
UK health economy.