Date of Award

2016

Degree Type

Thesis

Degree Name

Master of Science in Pharmaceutical Sciences

Department

Biomedical and Pharmaceutical Sciences

First Advisor

Cynthia Willey

Abstract

Background: Attention Deficit Hyperactivity Disorder (ADHD) is a mental health disorder characterized by functional impairment due to symptoms of inattention, impulsivity, and hyperactivity. Psychostimulant medications effectively reduce these symptoms, however there is little evidence regarding the factors associated with use of different types of stimulant medications.

Objective: To investigate factors associated with sustained release (SR) versus immediate release (IR) stimulant prescription for pediatric ADHD.

Methodology: A cross-sectional observational study was conducted using the 2012 National Ambulatory Medical Care Survey (NAMCS), a nationally representative sample of physician office visits. Independent predictors of SR stimulant medication prescription, as compared to IR stimulant prescription, were identified from logistic regression models.

Results: Our data set contained visits representative of 105,548,504 visits with an associated age of 4-17 years old (11.39% of all visits). Of these pediatric visits, there were 7,088,227 visits (7.56%) with an ADHD diagnosis code (ICD-9: 314.00, 314.01). The majority of pediatric ADHD visits were male (n=5,155,695, 72.74%). The most frequent age groups were 7 to 11 years (n=3,374,121, 47.60%) and 12-17 years (n=46,097, 42.97%), while the 4-6 year age group was less frequent (n=668,010, 9.42%). The most frequent race was White (n=4,771,295, 67.31%), while less frequent were Black race (n=1,229,675, 17.35%) and Hispanic race (n=956,710, 13.50%). The most frequent office region was the South (n=3,221,211, 45.44%). The most frequent pay types were private insurance (n=3,427,928, 48.36%) and Medicaid (n=2,473,735, 34.90%).

After applying our study inclusion criteria, there were 4,617,709 pediatric visits with IR or SR prescriptions. Of this visit sample, 3,431,741 had sustained release (74.35%) and 1,185,968 visits had immediate release stimulant prescriptions (25.68%). There were 1,969,116 visits with a combination of SR/IR (42.64%), which we included as SR in our modeling.

Our logistic modeling approach identified a number of non-significant sociodemographic predictors of SR prescription, relative to IR prescription. Compared with the 7-11 year old age group, the 12-17 year old group was 70% more likely to have a SR vs IR prescription (OR=1.695), while the 4-6 year old group was roughly 70% less likely to have SR than IR (OR=0.359). Relative to those with white race/ethnicity, those of black race (OR=2.183), Hispanic race (OR=2.223), and "Other" race (OR=2.717) had a non-significant but doubled likelihood of receiving an SR vs IR only prescription. Our logistic approach did not find evidence that sex or ADHD subtype were significant predictors of SR vs IR stimulant prescription. Overall, this modeling approach did not identify any significant sociodemographic predictors of SR vs IR only use.

Conclusions: In our nationally representative sample of pediatric ADHD office visits, visits of adolescent age or those with comorbid anxiety disorder had a higher likelihood of a SR stimulant drug mention than an IR mention. In contrast, visits with a diagnosis of autism and those in the Western region were less likely to have SR relative to an IR stimulant prescription. We did not find evidence to support disparities in SR versus IR stimulant prescriptions in visits of Black, Hispanic, or female children. These findings documented similarities and differences in ADHD medication prescription across sociodemographic groups that may be helpful for identifying office visits with a predisposition towards SR or IR stimulant prescription and to further understand the choice of ADHD drug for childhood ADHD.

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