Addressing Racial/Ethnic Differences in ADHD Diagnosis and Treatment Among Medicaid-insured Youth in California

Dinci Pennap, MPH,1 Mehmet Burcu, MS,1 Daniel J. Safer, MD,2 Julie M. Zito, PhD 1,3

MARYLAND CENTER FOR EXCELLENCE IN REGULATORY SCIENCE & INNOVATION

BackgroundPopulation based studies of Medicaid administrative claims

data document mental health service utilization in youth on the order of 50% - 60% lower among minority populations

Residential locale can be measured in terms of the degree to which two or more racial groups live separately from one another in a geographic area. Residential segregation‡ may imply differences in access and availability of services as well as cultural preferences that limit use of medical care

ObjectiveTo assess whether residential segregation of Hispanic youth

contributes to reduced treatment services for continuously enrolled Medicaid-insured youth in a large U.S. state

MethodsStudy Design & Population

A cross-sectional design was applied to the 2009 claims data of continuously enrolled youth 2 through 17 years of age, representing 83.7% of the state’s Medicaid youth population (N = 2,221,010)

Outcomes ADHD diagnosis• ICD-9-CM codes (314.xx) from outpatient and physician

filesStimulant use • At least 1 dispensing for methylphenidate or amphetamine

salts

Residential Segregation MeasureAs a proxy for residential segregation, regional Hispanic

composition was measured as a proportion of the Hispanic population in the Medicaid enrollee’s zip code of residence; characterized as less than 25%, 25-50%, and >50%

CovariatesAge group, gender, Medicaid eligibility category, and median

household income

ResultsContinuously enrolled Medicaid-insured youth were

predominately Hispanic (63.7%), <10 years old (54.2%), & eligible for Medicaid based on low family income (89.9%)

Overall, among ADHD diagnosed youth, 59.8% received at least 1 stimulant dispensing. Compared to White youth, Hispanic youth were 32% less likely to receive stimulant treatment following an ADHD diagnosis (Table 1)

After adjusting for covariates, the Hispanic to White differences in ADHD diagnosis and stimulant use were significantly reduced as regional Hispanic composition increased from <25% to >50% of the enrollees’ zip code of residence (Table 2)

Hispanic youth residing in highly segregated areas (>50% Hispanic composition) were:• More likely to have median household income <$50,000 (data

not shown)• 66% less likely to receive an ADHD diagnosis and 35% less

likely to receive a stimulant dispensing compared to White youth (Table 2)

Conclusions• Hispanic to White differences intensified with increasing

levels of regional Hispanic composition• Among ADHD diagnosed youth, Hispanic to White

differences in stimulant use were substantially smaller than the differences in ADHD diagnosis

• Residential segregation research should be pursued further

1Departments of Pharmaceutical Health Services Research and 3Psychiatry, University of Maryland, Baltimore, MD 2Departments of Psychiatry and Pediatrics, Johns Hopkins Medical Institutions, Baltimore, MD

Statistical AnalysesBivariate analyses were conducted to assess: 1) percent

prevalence of ADHD diagnosis; 2) percent of stimulant use among ADHD diagnosed youth

Multivariable analyses were used to examine Hispanic to White differences in ADHD diagnosis and stimulant use across levels of Hispanic residential segregation, adjusting for study covariates

N % Prevalence AOR 95% CI

ADHD Diagnosis 47,364 2.1

Race/Ethnicity

White 16,560 5.0 1.00 Ref.

Black 7,849 3.4 0.65 0.63 – 0.67

Hispanic 17,281 1.2 0.36 0.35 – 0.37

Other 5,674 2.3 0.39 0.38 – 0.40

Stimulant Use 28,334 59.8

Race/Ethnicity

White 10,887 65.7 1.00 Ref.

Black 4,458 56.8 0.67 0.63 – 0.71

Hispanic 9,488 54.9 0.68 0.65 – 0.72

Other 3,501 61.7 0.77 0.72 – 0.83

Table 1. Prevalence and adjusted odds ratio (AOR) of ADHD diagnosis and percent of stimulant use among Medicaid-insured youth in California in 2009

Table 2. Prevalence and adjusted odds ratio (AOR) of ADHD diagnosis and percent of stimulant use in White and Hispanic youth by regional Hispanic composition

Regional Hispanic Composition

< 25% 25% - 50% > 50%

% AOR 95% CI % AOR 95% CI % AOR 95% CI

ADHD Diagnosis

White 4.9 1.00 Ref. 5.1 1.00 Ref. 5.1 1.00 Ref.

Hispanic 1.7 0.43 0.41 – 0.46 1.4 0.37 0.36 – 0.38 1.1 0.34 0.33 – 0.35

Stimulant Use

White 66.8 1.00 Ref. 65.2 1.00 Ref. 64.8 1.00 Ref.

Hispanic 61.4 0.80 0.71 – 0.89 56.7 0.71 0.65 – 0.76 53.0 0.65 0.60 – 0.71

LimitationGeneralizability: Although comprehensive at the state level, the

data source represents only 14.6% of national Medicaid-insured youth

‡White, K, Haas, J.S, Williams, D.R. (2012). Health Services Research 47:3