A study of incidence, prevalence, treatment patterns, healthcare utilization, and costs of treatment of Attention Deficit Hyperactivity Disorder (ADHD) among Texas Medicaid preschoolers

Abstract

Attention Deficit Hyperactivity Disorder (ADHD) is the most common neurobehavioral disorder diagnosed in children and adolescents, affecting approximately 11% of children in the United States in 2011. Children are often diagnosed with ADHD before seven years of age. Yet, there is very little information about the diagnoses, treatments, healthcare utilization, and costs associated with ADHD in preschool children. The American Academy of Pediatrics recommends behavioral therapy as the first-line therapy for preschoolers, with a recommendation to prescribe medications only if behavioral therapy is unsuccessful in alleviating ADHD-related symptoms. For children in elementary school, combination therapy is recommended. Thus, the goal of the current study was to assess the epidemiology (i.e., prevalence and incidence), treatment patterns (i.e., adherence, persistence, augmentation, and switching), healthcare utilization, and costs in preschoolers diagnosed with ADHD using the Texas Medicaid dataset. Patients < 6 years of age diagnosed with ADHD (ICD-9 codes 314.00, 314.01) with continuous enrollment for a 6-month pre-index period and a 12-month post-index period between 2008 and 2013 were identified from the Texas Medicaid dataset. Epidemiology estimates were calculated for all the patients < 6 years of age diagnosed with ADHD. Treatment patterns, healthcare utilization, and costs were estimated for patients between 2 – 6 years of age. Based on the study inclusion criteria, we identified 10,877 patients in the overall cohort. A subsample from the overall cohort was selected for inclusion in the treatment pattern cohort (n = 8,833). The index date for the overall cohort was the ADHD diagnosis date. The index date for the treatment pattern cohort was the date of the first ADHD prescription. Prevalence and incidence estimates were calculated for all the patients < 6 years of age. Time-to-initiation, healthcare utilization, and costs were analyzed using the overall cohort. Treatment pattern outcomes (i.e., adherence, persistence, augmentation, and switching) were evaluated using the treatment pattern cohort. The study sample was further subcategorized into pharmacotherapy only, psychotherapy only, and combination therapy groups. The study covariates included patient demographic (i.e., age, gender, race/ethnicity, and urban/rural status), clinical (i.e., other psychotropics, other mental health diagnosis, medication duration of action, and medication class), and prior utilization (i.e., pre-index total costs, pre-index psychiatric visits, and pre-index non-psychiatric visits) characteristics. Bivariate and multivariate analyses were used to analyze the data. The prevalence of ADHD in preschoolers was estimated to be between 2.1% and 8.5% from years 2008 to 2012. Incidence estimates were stable and were estimated to be between 2.4% and 2.1% from years 2009 to 2012. Medication adherence, augmentation, and switching rates were higher in the combination therapy group as compared to the pharmacotherapy group. The combination therapy group had significantly higher healthcare utilization in all resource utilization categories except ADHD-related prescriptions, other mental health-related office-based, and inpatient visits. Similarly, medical, prescription, and total healthcare costs were also significantly higher in the combination therapy group as compared to the pharmacotherapy group except for the other mental health-related medical costs. In summary, the prevalence and incidence of ADHD in preschoolers is significant. Most of the patients received medication therapy followed by combination therapy and psychotherapy. A comparison of treatments revealed that combination therapy group had a higher healthcare burden as compared to the pharmacotherapy group. This study adds to the existing literature regarding ADHD in preschoolers, from a Medicaid perspective. Also, since Texas Medicaid provides coverage for nearly 50% of children in Texas these results have important implication for the state of Texas. The results of the current study will help identify the more important healthcare utilization and cost categories so as to develop a more targeted intervention approach for patients with ADHD. Further research is needed to understand the long-term effects of pharmacotherapy, psychotherapy, and combination therapy in preschoolers. More evidence is needed to identify the best treatment option for the management of ADHD in preschoolers.