Abstract
Objective: To assess the cost-utility, budget impact, and feasibility of the Thai Diagnostic Autism
Scale (TDAS) for Thai children
Methods: To assess the cost-utility analysis, a hybrid model between decision tree and Markov
model was used to compare TDAS and clinical diagnosis in the perspective of society. Input
parameters were obtained from primary data collection from five hospitals (Rajanagarindra
Institute of Child Development, Phayao Hospital, Suratthani Hospital, Dansai Crown Prince
Hospital and Bangplee Hospital), and literature review. The study outcomes were measured in
terms of total life-year costs, and quality-adjusted life-years (QALYs). All costs and outcomes
were discounted at an annual rate of 3%. Incremental cost-effectiveness ratio (ICER) was
estimated. One-way sensitivity analysis and probabilistic sensitivity analysis were also performed.
Budget impact analysis was also conducted based on the data from literature review and costutility analysis. The base-case analysis comparing scenario 1 (TDAS) versus scenario 2 (clinical
diagnosis) was assessed. One-way sensitivity analysis was performed. A five-year period of annual
budget, average budget, and net budget impact were reported. The feasibility test was
conducted by in-depth interviewing medical doctors and healthcare personnels. Several issues
such as TDAS acceptance, practical use were prior set up for interview.
Results: The base-case results of cost-utility analysis showed that patients with TDAS diagnosis
had total life-time cost of 1,511,151 THB, and QALYs of 15.55 years, while those with clinical
diagnosis had total life-time cost of 1,316,203 THB, and QALYs of 13.59 years. This yielded the
ICER of 99,682 THB/QALY, which was below the acceptable threshold of 160,000 THB/QALY. This
indicated that TDAS had 81.19% of being cost-effective at the acceptable threshold. The basecase results of budget impact analysis showed that on average TDAS increased 3,817,552
THB/year for the intervention cost but reduced 6,210,074 THB/year for autism treatment cost.
This led to net budget saving of 2,392,522 THB/year. The results of feasibility study showed that
healthcare personnels accepted TDAS as the benefit tool to assist suspected patients with
autism to access the right and quick diagnosis. TDAS can be applied to other outpatient services,
including child development clinics and child psychiatric clinics. In addition, it can be used in all
hospital levels where the specialists who can confirm diagnosis are available.
