The Diagnosis of Autism Spectrum Disorder in Low and Middle Income Countries: Concordance of Assessment Instruments in Jamaica
The high prevalence of ASD has encouraged development of new valid and reliable diagnostic tools. While the ADOS and ADI-R are widely used in diagnosis in High Income Countries (HIC), their administration requirements, including costly in person training, expensive test booklets and lengthy administration time, make them less suitable for Low and Middle Income Countries (LMIC). Yet, it is important that ASD be diagnosed accurately so that children with and without ASD receive appropriate interventions. The cost-efficiency and flexible administration requirements of the Childhood Autism Rating Scale (CARS) has made it an instrument of choice for ASD assessment in HIC, as well as LMIC countries, like Jamaica. There has been limited assessment of its diagnostic accuracy in LMIC.
The objective of this paper is to determine the concordance of the CARS, ADOS and ADI-R in Jamaica, a LMIC, to identify the most feasible instrument for use in this setting.
149 children, aged 2-8 years, previously diagnosed with ASD by an experienced clinician using the CARS were re-evaluated using the ADOS and ADI-R. The proportion of children confirmed as having ASD by ADOS, ADOS-2 and ADI-R was determined and mean CARS, ADI-R and ADOS scores compared using ANOVA, with significance at a 5% level.
The mean age of the sample was 64.4 (SD=21.6) months; the male female ratio was 6:1. All children (100%) were confirmed as having ASD using the ADOS, 98.7% (147/149) using ADOS 2 and 94.6% (141/149) using the ADI-R. Of the ten children whose ASD status was not confirmed by ADI-R or ADOS-2, seven did not reach the threshold in at least two domains of the ADI-R, two did not reach the threshold for the ADOS-2, and only one did not reach the threshold scores for either the ADOS-2 or ADI-R. Concordance between the ADI-R and ADOS and ADOS2 was 94.6% and 93.3% respectively. Total ADI-R ADOS and ADOS-2 domain scores were significantly higher for children classified with autism than for those classified autism spectrum (P<0.01, P<0.05).
The CARS, used by an experienced clinician, was shown to have high concordance in Jamaica. Use of this easily administered, economical and time efficient instrument by a clinician experienced in ASD, may be appropriate in other LMIC settings. The use of the CARS by clinicians of varying levels of experience with ASD should be evaluated before general recommendations for its use in these settings are made.