Association of Coexisting Conditions, Attention-Deficit/Hyperactivity Disorder Medication Choice, and Likelihood of Improvement in Preschool-Age Children: A Developmental Behavioral Pediatrics Research Network Study.

To determine whether conditions coexisting with attention-deficit/hyperactivity disorder (ADHD) in preschool-age children are associated with choice of stimulants or alpha-2 adrenergic agonists (A2As) and/or likelihood of improvement in ADHD symptoms. A retrospective electronic health record review of 497 children from 7 Developmental Behavioral Pediatrics Research Network (DBPNet) sites. Children were <72 months when treated with medication for ADHD from January 1, 2013 to July 1, 2017. We abstracted coexisting conditions, initial medication prescribed, and whether the medication was associated with improvement in symptoms. Analysis of improvement was adjusted for clustering by clinician and site. The median (interquartile range) child age at the time of initiation of ADHD medication was 62 (54-67) months. The most common coexisting conditions included language disorders (40%), sleep disorders (28%), disruptive behavior disorders (22.7%), autism spectrum disorder (ASD; 21.8%), and motor disorders (19.9%). No coexisting conditions were present in 17.1%; 1 in 36.8%, 2 in 26.8%, and ≥3 in 19.3%. Stimulants were initially prescribed for 322 (64.8%) and A2A for 175 (35.2%) children. Children prescribed stimulants were more likely to have no coexisting conditions than those prescribed A2A (22.3% vs. 7.4%;  < 0.001). Coexisting ASD and sleep disorder were associated with increased likelihood of starting A2As versus stimulants ( < 0.0005;  = 0.002). The association between medication treatment and improvement varied by number of coexisting conditions for 0, 1, 2, or ≥3, respectively (84.7%, 73.8%, 72.9%, 64.6%;  = 0.031). Children with ≥3 coexisting conditions were less likely to respond to stimulants than children with no coexisting conditions (67.4% vs. 79.9%;  = 0.037). Among preschool-age children with ADHD, those with ≥3 coexisting conditions were less likely to respond to stimulants than those with no coexisting conditions. This was not found for A2A, but further research is needed as very few children with no coexisting conditions were treated with A2A.