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The American Journal of Managed Care March 2019
Fragmented Ambulatory Care and Subsequent Emergency Department Visits and Hospital Admissions Among Medicaid Beneficiaries
Lisa M. Kern, MD, MPH; Joanna K. Seirup, MPH; Mangala Rajan, MBA; Rachel Jawahar, PhD, MPH; and Susan S. Stuard, MBA
Incorrect and Missing Author Initials in Affiliations and Authorship Information
From the Editorial Board: Austin Frakt, PhD
Austin Frakt, PhD
Implications of Eligibility Category Churn for Pediatric Payment in Medicaid
Deena J. Chisolm, PhD; Sean P. Gleeson, MD, MBA; Kelly J. Kelleher, MD, MPH; Marisa E. Domino, PhD; Emily Alexy, MPH; Wendy Yi Xu, PhD; and Paula H. Song, PhD
Factors Influencing Primary Care Providers’ Decisions to Accept New Medicaid Patients Under Michigan’s Medicaid Expansion
Renuka Tipirneni, MD, MSc; Edith C. Kieffer, PhD, MPH; John Z. Ayanian, MD, MPP; Eric G. Campbell, PhD; Cengiz Salman, MA; Sarah J. Clark, MPH; Tammy Chang, MD, MPH, MS; Adrianne N. Haggins, MD, MSc; Erica Solway, PhD, MPH, MSW; Matthias A. Kirch, MS; and Susan D. Goold, MD, MHSA, MA
Did Medicaid Expansion Matter in States With Generous Medicaid?
Alina Denham, MS; and Peter J. Veazie, PhD
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Access to Primary and Dental Care Among Adults Newly Enrolled in Medicaid
Krisda H. Chaiyachati, MD, MPH, MSHP; Jeffrey K. Hom, MD, MSHP; Charlene Wong, MD, MSHP; Kamyar Nasseh, PhD; Xinwei Chen, MS; Ashley Beggin, BS; Elisa Zygmunt, MSW; Marko Vujicic, PhD; and David Grande, MD, MPA
Common Elements in Opioid Use Disorder Guidelines for Buprenorphine Prescribing
Timothy J. Atkinson, PharmD, BCPS, CPE; Andrew J.B. Pisansky, MD, MS; Katie L. Miller, PharmD, BCPS; and R. Jason Yong, MD, MBA
Specialty Care Access for Medicaid Enrollees in Expansion States
Justin W. Timbie, PhD; Ashley M. Kranz, PhD; Ammarah Mahmud, MPH; and Cheryl L. Damberg, PhD
Gender Differences in Prescribing of Zolpidem in the Veterans Health Administration
Guneet K. Jasuja, PhD; Joel I. Reisman, AB; Renda Soylemez Wiener, MD, MPH; Melissa L. Christopher, PharmD; and Adam J. Rose, MD, MSc
Cost Differential of Immuno-Oncology Therapy Delivered at Community Versus Hospital Clinics
Lucio Gordan, MD; Marlo Blazer, PharmD, BCOP; Vishal Saundankar, MS; Denise Kazzaz; Susan Weidner, MS; and Michael Eaddy, PharmD, PhD
Health Insurance Literacy: Disparities by Race, Ethnicity, and Language Preference
Victor G. Villagra, MD; Bhumika Bhuva, MA; Emil Coman, PhD; Denise O. Smith, MBA; and Judith Fifield, PhD

Access to Primary and Dental Care Among Adults Newly Enrolled in Medicaid

Krisda H. Chaiyachati, MD, MPH, MSHP; Jeffrey K. Hom, MD, MSHP; Charlene Wong, MD, MSHP; Kamyar Nasseh, PhD; Xinwei Chen, MS; Ashley Beggin, BS; Elisa Zygmunt, MSW; Marko Vujicic, PhD; and David Grande, MD, MPA
Nearby provider supply did not affect identification of usual sources of primary or dental care among new Medicaid enrollees. Strategies to improve access are needed.
Primary Care and Dental Practice Database

We constructed a database of Medicaid-participating primary and dental care providers in and around Philadelphia. We aggregated providers within office locations for the purposes of geospatial analyses. Primary care providers included physicians, nurse practitioners, and physician assistants. As described in a prior study,17 we used SK&A (2014), a proprietary database, to identify all primary care providers in and near Philadelphia participating in Medicaid. We supplemented this database with provider directories from the Philadelphia-based Medicaid plans and public lists of federally qualified health centers. Practices were contacted by phone to verify their address, the number of practicing clinicians, and each clinician’s full-time equivalent (FTE) workload to calculate an aggregate FTE for each office. Dental care providers consisted of general practice dentists who treated adults. We utilized the 2014 American Dental Association masterfile as the initial file and supplemented it with the National Provider Identifier dentist registry and the Medicaid provider file from Pennsylvania’s Department of Human Services. We defined the number of dental FTEs in a dental office based on the number of offices for which a dentist works.24

Census Tract Primary Care and Dental Care Provider Supply

Using the practice file described previously and population density data from the American Community Survey, we calculated a Medicaid adult population per provider ratio for each Census tract using the 2-step floating catchment area (2SFCA) method to estimate the ratio of Medicaid-enrolled adults per Medicaid-participating provider based on a 5-minute travel time. The 2SFCA method accounts for the providers in and around Philadelphia-based Census tracts and the population around a provider office.24 In addition, the 2SFCA method helps account for the modifiable areal unit problem, or the error introduced into spatial analyses by drawing unit borders and by aggregating units.25 We used ArcGIS 10.3 to account for traffic history and street restrictions in order to accurately measure travel times.

We defined low-provider areas as those with 5 or more contiguous Census tracts in the lowest quintile of supply—the population per provider ratio within a 5-minute travel time of a Census tract.17 Our goal was to identify geographic clusters with lower supply (as opposed to isolated Census tracts that may be adjacent to higher supply areas) to more accurately reflect experiences of patients seeking usual sources of care within and outside of their neighborhood. We utilized a relative instead of absolute measure of supply because there is no agreed-upon definition of the ideal adult population per provider ratio in urban areas for either primary or dental care.

Data Analyses

For all analyses, we evaluated primary and dental care access separately. We assessed whether living in a low-provider supply area for primary or dental care was associated with having a usual source of primary or dental care, respectively. We used multivariable logistic regression models clustered at the level of Census tracts adjusting for age, gender, race/ethnicity, self-rated health, educational attainment, and employment status. In an additional analysis, we used the aforementioned models but changed the exposure of primary care and dental care supply to continuous measures of adult population per provider ratios. As a sensitivity analysis, we used 10-minute travel times to define supply. A 2-sided P <.05 was considered statistically significant. All analyses were carried out using Stata version 14.0 (StataCorp, LLP; College Station, Texas).


Of 1000 contacted individuals, 312 completed the survey. Among respondents, 168 reported being enrolled in Medicaid and were previously uninsured. These individuals (Table 1) were predominantly female (60.1%), 45 years or older (67.9%), African American (65.5%), and non-Hispanic (86.3%). A total of 59.5% had a high school education or less, and few (35.1%) were employed full time or part time. The majority (78.0%) reported having good to excellent health.

Within the study cohort, 112 of 168 (66.7%) had a usual source of primary care and 71 of 168 (42.3%) had a usual source of dental care. Those with a usual source of primary and dental care did not differ significantly from those without a usual source based on their sociodemographic characteristics. However, those with a usual source of dental care were more likely to have better self-reported health (excellent, very good, good) compared with respondents without a usual source of dental care (63/71 [88.7%] vs 56/84 [66.7%], respectively; P = .001). For primary care, there were no significant differences in self-reported health (P = .56).

Table 2 shows the unadjusted and adjusted associations between the supply of providers for respondents’ Census tracts and respondents’ identification of a usual source of primary and dental care. Individuals living in lower-supply areas were as likely to identify a usual source of primary or dental care as those living in higher-supply areas. These findings were no different when supply was modeled as a continuous variable (adult population per provider ratio) or when using 10-minute travel times.

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