Autism screening and diagnostic outcomes among toddlers born preterm

To examine the Modified Checklist for Autism in Toddlers, Revised, with Follow-Up (M-CHAT-R/F), with follow-up screening and diagnostic outcomes for children born preterm. A secondary aim was to examine diagnostic evaluation attendance after screening to inform clinical practice.

Using a cross-sectional design, 9725 toddlers (4951 males; 4774 females) whose gestational age was reported were screened at 15-month, 18-month, or 24-month well-child visits; screen-positive children were invited for an autism evaluation. Screening measure performance and diagnostic outcomes were evaluated according to preterm classification (Screening: n_ExtPreterm = 111; n_VeryPreterm = 186; n_ModPreterm = 1122; n_FullTerm = 8306; Evaluation: n_ExtPreterm = 27; n_VeryPreterm = 21; n_ModPreterm = 86; n_FullTerm = 301).

Screen-positive rates were highest for children born extremely preterm (51.35%) and lowest for children born at term (6.95%). Evaluation attendance for screen-positive cases did not differ according to preterm classification. Rates of autism diagnoses differed depending on preterm birth status: for children born extremely preterm, it was 16.05%; for children born very preterm, it was 2.00%; for children born moderately preterm, it was 2.89%; and for children born at term, it was 1.49%. M-CHAT-R/F sensitivity decreased with increasing gestational age, whereas specificity improved with increasing gestational age. Positive predictive value was highest for children born extremely preterm and children born at term. Negative predictive value was consistently strong across all groups. The likelihood ratio for positive screening increased with gestational age.

The sensitivity and specificity of the M-CHAT-R/F are acceptable in toddlers born preterm. Autism screening-positive rates and prevalence increased with earlier preterm birth. Those born extremely preterm showed the greatest likelihood of an autism diagnosis; screening should not be delayed based on adjusted age.