412 - Predictive validity of developmental screening using the Infant Toddler Checklist at the 18-month visit and neurodevelopmental consultation at an average age of 8 years

Poster Number: 412
Publication Number: 412.102

Background: The Infant Toddler Checklist (ITC) was developed for identification of children, 6-24 months, at risk of developing a communication impairment. In the laboratory setting, the ITC has been shown to have adequate concurrent and predictive validity for detection of a range of developmental concerns. In the primary care setting, we have assessed the predictive validity of the ITC, using parent-reported developmental diagnosis at age 3-5 years and teacher-reported school readiness at age 4-6 years as the criterion measures.

Objective: The primary objective was to examine the predictive validity of the ITC at the 18-month visit using later neurodevelopmental consultation as the criterion measure. A secondary objective was to examine whether positive developmental screening was associated with physician-related outcomes.

Design/Methods: Using a prospective design, parents completed the ITC at the 18-month visit in primary care practices participating in a research network in Toronto, Canada (www.targetkids.ca). Health care utilization was collected from health administrative databases, via linkage using the child’s provincial health insurance number. Covariates included child and family characteristics. We calculated screening test properties and used multivariable negative binomial regression to estimate rate ratios (RR).

Results: Of 1,460 children (mean age 18 months), 160 (11.0%) had a positive ITC. At mean follow-up of 6.5 (SD 2.2) years (mean age 8 years), 38 (2.6%) had a neurodevelopmental consultation. Using neurodevelopmental consultation as the criterion, a positive ITC had 40% sensitivity (95% CI 24%-57%), 90% specificity (95% CI 88%-91%), and 10% false positive rate (95% CI 9%-12%). Children with a positive ITC, compared to children with a negative ITC had higher rates of: neurodevelopmental consultation (RR=2.78, 95% CI 1.37-5.67); special pediatric consultation (RR=1.75, 95% CI 1.17-2.61); scheduled primary care visit billings (RR=1.11, 95% CI 1.02-1.21); unscheduled primary care or minor visit billings (RR=1.44, 95% CI 1.14-1.81), after adjusting for covariates.

Conclusion(s): The ITC demonstrated high specificity suggesting that most children with a negative ITC screen will not receive a neurodevelopmental consultation at an average age of 8 years, and low false positive rates, minimizing over-diagnosis. The ITC had low sensitivity as is common with developmental screening tools administered in early childhood. A positive ITC was associated with several physician-related outcomes. These findings highlight the importance of ongoing developmental surveillance and screening of young children.