Developmental screening at 18 months using the Nipissing District Developmental Screen.

Objectives: The Canadian Paediatric Society recommends an enhanced 18-month visit, including the use of a developmental screening tool to stimulate discussion with parents about their child's development, and notes the Nipissing District Developmental Screen (NDDS) is a widely used tool. We examined the predictive validity of the NDDS in children at average-risk for developmental delay and the association between positive screening and health care utilization (HCU). Methods: Using a prospective design, parents completed the NDDS at the 18-month primary care visit in Toronto, Canada. Child health insurance number was used to link with health administrative databases to collect HCU data. We calculated screening test properties using later neurodevelopmental consultation as the criterion measure and used multivariable negative binomial regression to estimate adjusted rate ratios (aRR) for each HCU type. Results: Of 802 children (mean age 18 months), 35.5% screened NDDS positive. Mean age at follow-up was 8 years, 20 (2.5%) had a neurodevelopmental consultation, and 94 (11.7%) had a special paediatric consultation/assessment, including developmental and/or behavioural care. Screening test properties were: 50% sensitivity (95% CI 27%, 73%), 65% specificity (95% CI 61%, 68%), 35% false positive rate (95% CI 31%, 40%). A positive NDDS was associated with only 1 of 7 HCU types. Conclusions: The sensitivity and specificity of the NDDS is inadequate for a developmental screening tool at 18 months, and the false positive rate is unacceptably high. The screening test properties of other widely used developmental screening tools is discussed, noting their low sensitivity, higher specificity, and lower false positive rates. Trial registration: Clinicaltrials.gov (NCT01869530).