Background: Children with ADHD have 2 to 3 times increased health care utilization and annual costs once diagnosed, but little is known about utilization patterns early in life, prior to diagnosis. Quantifying early health services use among children later diagnosed with ADHD could help us understand the early life impact of the disorder and uncover health care utilization patterns associated with higher ADHD risk. Methods: Electronic health record (EHR) data from the Duke University Health System (DUHS) was analyzed for patients born October 1, 2006–October 1, 2016. Those with at least two well-child visits before age 1 were grouped as ADHD or not ADHD based on retrospective billing codes. Adjusted odds ratios (AORs) for hospital admissions, procedures, emergency department (ED) visits, and outpatient clinic encounters before age 1 were compared between groups via logistic regression controlling for sex, race, and ethnicity. Results: ADHD diagnoses were identified in 1,315 (4.4%) of 29,929 patients meeting criteria. Before age 1, individuals with ADHD had 60% increased odds of hospital admission, 58% increased odds of visiting the emergency department, and 41% increased odds of procedures (p < .0001), including 4.7-fold increased odds of blood transfusion (p < .0001). They also had more outpatient clinic visits (μ = 14.7 vs. μ = 12.5, p < .0001), including 52% increased odds of visiting a medical specialist, 38% increased odds of visiting a surgical specialist, 70% increased odds of visiting a neonatologist, and 71% increased odds of visiting an ophthalmologist (p < .0001 for all AORs). In addition, individuals with ADHD had 6-fold increased odds of visits related to child abuse and neglect (p = .0010). Conclusions: Children later diagnosed with ADHD were more likely to be admitted to the hospital, visit the ED, and visit specific medical and surgical services before age 1. Future work will identify patterns of health interactions unique to ADHD to stratify ADHD risk.
