Background:

Early intensive applied behaviour analysis-based interventions are intensive interventions for autistic children that are often delivered on a one-to-one basis for 20–50 hours per week.

Objectives:

To evaluate the clinical effectiveness and cost-effectiveness of early intensive applied behaviour analysis-based interventions for autistic children, based on current evidence.

Methods:

A systematic review and individual participant data meta-analysis were conducted to evaluate the clinical effectiveness of an early intensive applied behaviour analysis-based intervention for autistic children. An economic analysis included a review of existing analyses and the development of a new model.

Results:

Twenty studies were included in the clinical review. Individual participant data were retrieved from 15 of these studies. Results favoured the interventions when assessing adaptive behaviour after 2 years compared with treatment as usual/eclectic interventions (mean difference 7.00, 95% confidence interval 1.95 to 12.06). In analyses of cognitive ability (intelligence quotient), results favoured the interventions by approximately 10 points after 1 year (mean difference 9.16, 95% confidence interval 4.38 to 13.93) and 2 years (mean difference 14.13, 95% confidence interval 9.16 to 19.10). Evidence for other outcomes was limited and meta-analyses were generally inconclusive. There was no evidence that the effect of the interventions varied with characteristics of the children, but data were limited. Adopting a £30,000 per quality-adjusted life-year threshold, the results of the cost-effectiveness analysis indicate that early intensive applied behaviour analysis-based interventions would need to generate larger benefits or cost savings to be cost-effective. Adopting a public sector perspective and making pessimistic assumptions about long-term effects, the incremental cost-effectiveness ratio for early intensive applied behaviour analysis-based therapy compared with treatment as usual is £189,122 per quality-adjusted life-year. When optimistic assumptions are made, the incremental cost-effectiveness ratio is £46,768 per quality-adjusted life-year. Scenario analyses indicated that these interventions can potentially be cost-effective if long-term improvements persist into adulthood, or if they have significant impact on educational placement. Care should be taken when interpreting these scenarios owing to the limited data.

Limitations:

All included studies were at risk of bias, there was substantial heterogeneity and effects varied considerably across studies. The effect of intervention on autism symptom severity, language development and school placement remains uncertain because of the limited data. The long-term effects are unclear owing to a lack of follow-up data.

Conclusions:

This review found limited evidence that early intensive applied behaviour analysis-based interventions may improve cognitive ability and adaptive behaviour, but the long-term impact of the interventions remains unknown. The economic analysis is constrained by the limited effectiveness evidence, but suggests that these interventions are unlikely to be cost-effective unless clear long-term benefits, or a substantial change in which schools children attend, can be identified.

Future work:

Further studies into the effectiveness of early intensive applied behaviour analysis-based interventions may be warranted if they include well-defined, alternative interventions as comparators and collect relevant outcomes. Consideration should be given to future studies that not only address whether or not early intensive applied behaviour analysis-based interventions are clinically effective, but also aim to identify which components of early intensive applied behaviour analysis-based interventions might drive effectiveness.

Study registration:

This study is registered as PROSPERO CRD42017068303.

Funding:

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 35. See the NIHR Journals Library website for further project information.

Article history

The research reported in this issue of the journal was funded by the HTA programme as project number 16/104/15. The contractual start date was in July 2017. The draft report began editorial review in May 2019 and was accepted for publication in December 2019. 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 reviewers 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.

Declared competing interests of authors

none