The Role of Residential Segregation in Disparity Research: A Case Example of ADHD Diagnosis and Treatment Dinci Pennap, MPH, 1 Mehmet Burcu, MS, 1 Daniel J. Safer, MD, 2 Julie M. Zito, PhD 1,3 1 Departments of Pharmaceutical Health Services Research and 3 Psychiatry, University of Maryland, Baltimore, MD 2 Departments of Psychiatry and Pediatrics, Johns Hopkins Medical Institutions, Baltimore, MD Conceptually, a low mix of minority (to White) neighbors has been identified as signaling practical differences in access and availability of services as well as cultural preferences that may limit use of medical care This study uses the conceptual model underlying the interaction of race/ethnicity and region of residence in terms of the extent of racial/ethnic residential segregation We selected the cohort from the Medicaid-insured youth population of the Pacific state with the largest Hispanic population to address the question: Does residential segregation of Hispanic youth contribute to reduced ADHD treatment services for Medicaid-insured youth? Background Methods Study Design and Population Retrospective cross-sectional study Computerized data from the 2009 Medicaid Analytical eXtract (MAX) files of a U.S. Pacific state for continuously enrolled Medicaid-insured youth MAX data included enrollment, outpatient hospital clinic and physician files, and dispensed prescription drug files MAX data in the zip code of enrollee’s residence were linked to the U.S. Census Bureau’s zip code tabulation area (ZCTA) files for information on regional median household income s and race/ethnic composition Outcome Measures ADHD diagnosis Clinician-reported ADHD diagnosis was assessed using ICD-9-CM codes (314.xx) from outpatient and physician files At least 2 ADHD service claims on separate days were required Stimulant use Included dispensings for all oral forms of methylphenidate, amphetamine products Main Independent Variables Race/ethnicity: White, African American, Hispanic, and other Regional Hispanic composition: Defined as the proportion of Hispanic population living in the Medicaid enrollee’s zip code of residence and categorized as 50% Other Covariates Sociodemographic characteristics: Age, gender, and median annual household income in the Medicaid enrollee’s zip code of residence Medicaid eligibility categories: Temporary Assistance for Needy Families (TANF); Children's Health Insurance Program (CHIP); foster care; youth with disabilities [Supplemental Security Income (SSI)] This project was funded by the Food and Drug Administration (FDA), Centers of Excellence in Regulatory Science and Innovation (CERSI), minority health award grant number 1U01FD The opinions expressed in this article are those of the authors and not intended to represent the opinions of the United States Food and Drug Administration Correspondence to Julie M. Zito, PhD Conclusions & Implications Conclusions There were 2.2 million continuously enrolled youth, representing 83.7% of the state’s Medicaid youth population (data not shown) Continuously-enrolled youth were predominately Hispanic (63.7%) and 50% Hispanic composition were more likely to have annual household income <$50,000/year (data not shown) Overall, among continuously-enrolled youth, 2.1% received ADHD diagnosis, and among ADHD diagnosed youth, 59.8% received at least 1 stimulant dispensing (Table 1) Compared to White youth, Hispanic youth were less likely to receive 1) ADHD diagnosis, and 2) stimulant treatment following an ADHD diagnosis (Table 1). However, White to Hispanic disparities were greater for ADHD diagnosis than for stimulant treatment Compared to White youth, the odds of a Hispanic youth receiving an ADHD diagnosis or stimulant treatment was significantly lower as residential Hispanic composition increased (Table 2) Regional Hispanic Composition < 25%25% - 50%> 50% %AOR95% CI%AOR95% CI%AOR95% CI ADHD Diagnosis White Ref Ref Ref. Hispanic – – – 0.35 Stimulant Use White Ref Ref Ref. Hispanic – – – 0.71 N% PrevalenceAOR95% CI ADHD Diagnosis47, Race/Ethnicity White1, Ref. Black7, – 0.67 Hispanic17, – 0.37 Other5, – 0.40 % of ADHD Diagnosed Youth Stimulant Use28, Race/Ethnicity White10, Ref. Black4, – 0.71 Hispanic9, – 0.72 Other3, – 0.83 Results Hispanic to White differences in ADHD treatment service utilization intensified with increasing levels of regional Hispanic composition Cultural preference, consumer education, and institutional bias (i.e. structural aspects of health care delivery system) could account for minority usage patterns and future research could shed light on these disparities Acknowledgements Table 1. Annual prevalence (%) and adjusted odds ratio (AOR) of ADHD diagnosis and stimulant use among Medicaid-insured youth by race/ethnicity Table 2. The role of regional Hispanic composition on Hispanic to White differences in annual prevalence (%) and adjusted odds ratio (AOR) of ADHD diagnosis and stimulant use