Cost-effectiveness of cognitive-behavioral therapy versus treatment as usual for anxiety disorders in children with autism spectrum disorder

Highlights

• CBT had a high probability to be more effective compared to TAU.

• The probability that either CBT or TAU is more costly did not differ much.

• CBT seems a cost-effective intervention to treat anxiety disorders in ASD.

Abstract

The study's aim was to evaluate the cost-effectiveness of CBT compared to treatment as usual (TAU). In total, 49 children aged 8–18 years with ASD and comorbid anxiety disorders, and their parents, participated; 24 were assigned to CBT and 25 were assigned to TAU. Outcome measures were the percentage of children free from their primary anxiety disorder and quality adjusted life years (QALYs). Costs were measured using a retrospective cost-questionnaire. Effects and costs were assessed at pre-, post-, and three months after treatment. Effects and costs were not statistically different between CBT and TAU, however the incremental cost-effectiveness ratio (ICER) demonstrated that CBT dominates TAU. Bootstrapped ICERs demonstrated that CBT has a high probability to be more effective than TAU, however, the probability that either CBT or TAU is more costly did not differ much. Secondary analyses demonstrated fairly robust results. CBT seems a cost-effective intervention compared to TAU, however, long-term follow-ups and comparisons between CBT and specific TAUs are necessary. Cost-effectiveness analyses may help inform policy makers to decide how to treat anxiety disorders in children with ASD.

Introduction

Anxiety disorders in children with autism spectrum disorders (ASD) are among the most common comorbid disorders (e.g., Simonoff et al., 2008) and are found to be related to a higher life interference (Farrugia & Hudson, 2006), a lower quality of life (Steensel, Bögels, & Dirksen, 2012), as well as additional societal costs (Steensel, Dirksen, & Bögels, 2013). Primarily, children with ASD suffer from chronic impairments in the social, communicative and repetitive domain (APA, 2000), and these ASD characteristics may be exacerbated by comorbid anxiety disorders (e.g., Wood & Gadow, 2010).

A number of studies have examined the effectiveness of cognitive-behavioral therapy (CBT) for the treatment of anxiety disorders in ASD and all have reported positive results; a substantial percentage of children being free from their primary anxiety disorder after treatment (i.e., 71%; Chalfant, Rapee, & Carroll, 2007), a substantial percentage of children being free from all anxiety disorders at post-treatment (i.e., 53%; Wood et al., 2009), and an overall decrease in anxiety levels (Chalfant et al., 2007, Reaven et al., 2009, Reaven et al., 2012, Sofronoff et al., 2005, Sung et al., 2011, Wood et al., 2009). Several studies have also compared CBT to a waitlist condition (Chalfant et al., 2007, Reaven et al., 2009, Sofronoff et al., 2005, Wood et al., 2009) and all studies have reported CBT to be superior compared to waitlist (no treatment) based on parental report. Thus, there is a growing body of evidence supporting the effectiveness of CBT for the treatment of anxiety disorders in ASD, however, less is known about the cost-effectiveness of CBT in relation to other treatments for these patients.

In cost-effectiveness analyses, the clinical outcomes as well as the costs of an intervention are compared to an alternative intervention in order to determine which treatment is the most cost-effective. An intervention is said to dominate the other when this intervention results in higher gains and lower costs. The incremental cost-effectiveness ratio (ICER) can be calculated which represents the ratio of the net increase in costs to the net increase in effectiveness (Palmer, Byford, & Raftery, 1999). Studies that have compared both costs as well as clinical outcomes (effectiveness) – i.e., conducted a cost-effectiveness analysis – for the treatment of anxiety disorders in children with ASD are lacking. Also, we have identified only three studies that have compared the effectiveness of CBT to other treatment options for anxiety in the ASD-population (Reaven et al., 2012, Storch et al., 2013, Sung et al., 2011) which will be discussed next.

The study of Sung et al. (2011) randomly assigned children with ASD to CBT (n = 36) or a social-recreational program (n = 34) which consisted of a variety of age-appropriate leisure activities. After having followed either CBT or the social-recreational program, children with ASD reported a decrease in anxiety levels, and no evidence was found for one intervention being more effective than the other. The study of Reaven and colleagues (2012) randomly assigned children to either CBT (n = 24) or TAU (n = 26). TAU in the study by Reaven et al. (2012) consisted of (1) medication, (2) social skills training, (3) bully-proofing programs, (4) individual psychosocial interventions, or (5) family focused interventions. The authors found evidence for CBT to outperform TAU; i.e., at post-treatment clinical severity ratings of the anxiety disorders were lower in CBT compared to TAU, and while a significant reduction in the total number of anxiety disorders was found in CBT, this result was not found in TAU. Furthermore, at post-treatment, families in TAU were invited to participate in CBT and 93% of the families agreed (Reaven et al., 2012), suggesting that TAU was not sufficient for treating anxiety disorders. In the study by Storch et al. (2013) 24 children were assigned to CBT and 21 to TAU (which consisted of interventions – psychotherapy, medication management or family treatment/education – targeting anxiety or ASD symptoms. Large group differences in favor of the CBT condition were found with respect to anxiety severity. In addition, it was found that 75% of the children in CBT were treatment responders versus only 14% of the children in TAU.

In sum, there is growing evidence for CBT to be effective for the treatment of anxiety disorders in children with ASD, however, studies comparing the effectiveness of CBT to other interventions are rare. The cost-effectiveness of CBT compared to other treatments for anxiety in children with ASD has not yet been examined. The aim of this study was to investigate the cost-effectiveness of CBT, as compared to TAU, for the treatment of anxiety disorders in children with ASD.