779 - An Examining of Children with Late Autism Diagnoses despite Positive Primary Care Autism Screening

Publication Number: 779.3935

Zachary T. Tripp, University of Utah, Salt Lake City, UT, United States; Paul Carbone, Univeristy of Utah, Salt Lake City, UT, United States; Michele Villalobos, university of utah, Salt Lake City, UT, United States; Ashley Stuart, University of Utah School of Medicine, Salt Lake City, UT, United States

Background: Autism screening at 18- and 24-month primary care visits can facilitate early diagnosis and improve developmental outcomes. Many children with positive screens are diagnosed with autism early ( < 48 months) but some are still diagnosed late (>48 months) and the factors associated with late diagnoses are not well studied.

Objective: Among children diagnosed with autism who had positive primary care autism screens (the Parent’s Observation of Social Interactions [POSI]), we aimed to: (1) compare demographic characteristics and POSI data between those with early versus late diagnoses and 2) perform a qualitative analysis to identify themes of late diagnoses.

Design/Methods: We examined electronic health records data among children with autism who attended 18- and 24-month visits and screened positive on the POSI between 7/2018-7/2024. The cohort ranged in age 3.5-8.9 years at the time of the data pull. We compared demographic, screening and referral data of children with early versus late autism (sex, race, ethnicity, childhood opportunity index (COI), insurance, POSI items and total scores, age of diagnosis). We performed manual chart reviews of children with late diagnoses to identify themes in delayed autism identification despite positive screening.

Results: Among 113 autistic children with positive POSIs, 95 were diagnosed early (84%) and 18 (16%) were diagnosed late. Those with late diagnoses where less likely to receive referrals for developmental evaluation (39% vs 64%, P=0.04) and were diagnosed on average 26 months later than children with early diagnoses (31.5 vs 57.2 months, P< 0.001). In comparing children diagnosed early versus late we found no differences in sex, race, ethnicity, COI and insurance (Table 1). At the 24-month visit, children with late diagnoses had lower total POSI scores and were less likely to fail one POSI item, Does your child look at you when you call his or her name? (Table 2). Manual chart review of children with late diagnoses revealed 4 themes: Children with complex autism presentations, provider wait-and-see approach, and parental difficulty navigating and engaging with the system (Table 3).

Conclusion(s): We found no demographic disparities among children with late vs early autism diagnoses. Based on POSI and referral data, those with later diagnoses may have more subtle characteristics of autism. Manual chart reviews show multiple child, parent, provider and system level factors that may lead to late diagnoses. Some late diagnoses may be due to complex or subtle presentations while others may be due to modifiable provider or system level factors.

Table 1. Child/family characteristics and comparisons among children with early versus late autism diagnosis
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Table 2. Comparisons of the children with late versus early autism diagnoses who screened positive on the Parent’s Observation of Social Interactions (POSI) at the 18- and/or 24-month visit
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Table 3. Themes identified from manual chart review of children with late autism diagnoses despite positive primary care autism screens at the 18- and/or 24-month visit
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