Primary Care Autism Screening with the Parent's Observations of Social Interactions

To report results of the Parent's Observations of Social Interactions (POSI) and identify associations between POSI results with referrals for developmental evaluations and autism diagnoses.

We examined data from electronic health records of POSI-screened children attending 18- and 24-month health supervision visits from July 2018 to July 2022 for POSI screening results and autism diagnoses. Descriptive statistics and regression models were used for analysis.

In 6669 POSI-screened children (age at follow-up, 42-107 months), 1065 of 4228 children screened at 18 months (25.2%) and 851 of 4896 children at 24 months (17.4%) screened positive. In 1079 children with positive POSI screenings, 233 children (21%) were referred for developmental evaluation. Autism was diagnosed in 184 of all 6669 children (2.8%). The POSI sensitivity for autism was 66.4% (95% CI 59.2-72.8%) and the positive predictive value was 9.2% (95% CI 7.4-10.6%). A positive POSI increased the likelihood of autism diagnosis at 18 months (adjusted odds ratio, 5.21; 95% CI 3.45-7.86) and 24 months (adjusted odds ratio 10.21; 95% CI 7.07-14.76). Autism was diagnosed 13 months earlier in children with a positive rather than negative POSI (35.5 vs 48.1 months; P < 0.001).

The POSI is a sensitive screening instrument for autism with a low positive predictive value (high percentage of false positive screenings), indicating the need for clarification about which children require further evaluation. Screening positive on the POSI was associated with a greater likelihood and earlier diagnosis of children with autism.