Rural and frontier access to mental health prescribers and nonprescribers: A geospatial analysis in Oregon Medicaid

Abstract

Objective: Medicaid enrollees in rural and frontier areas face inadequate access to mental health services, but the extent to which access varies for different provider types is unknown. We assessed access to Medicaid-participating prescribing and nonprescribing mental health clinicians, focusing on Oregon, which has a substantial rural population.

Methods: Using 2018 Medicaid claims data, we identified enrollees aged 18-64 with psychiatric diagnoses and specialty mental health providers who billed Medicaid at least once during the study period. We measured both 30- and 60-minute drive time to a mental health provider, and a spatial access score derived from the enhanced 2-step floating catchment area (E2SFCA) approach at the level of Zip Code Tabulation Areas (ZCTAs). Results were stratified for prescribers and nonprescribers, across urban, rural, and frontier areas.

Results: Overall, a majority of ZCTAs (68.6%) had at least 1 mental health prescriber and nonprescriber within a 30-minute drive. E2SFCA measures demonstrated that while frontier ZCTAs had the lowest access to prescribers (84.3% in the lowest quintile of access) compared to other regions, some frontier ZCTAs had relatively high access to nonprescribers (34.3% in the third and fourth quartiles of access).

Conclusions: Some frontier areas with relatively poor access to Medicaid-participating mental health prescribers demonstrated relatively high access to nonprescribers, suggesting reliance on nonprescribing clinicians for mental health care delivery amid rural workforce constraints. Efforts to monitor network adequacy should consider differential access to different provider types, and incorporate methods, such as E2SFCA, to better account for service demand and supply.

Keywords: access to care; mental health; provider networks; rural disparities.

Figure 1:

Mental health patient density and mental health provider locations across Oregon, based on Medicaid claims data, 2018 Notes: Left panel shows the full state of Oregon; right panel zooms in on the Portland metropolitan area. Mental health patient counts are shown for each ZCTA, and counts less than or equal to 10 are suppressed. Prescribers include psychiatrists, mental health nurse practitioners, and clinicial nurse specialists; non-prescribers include psychologists, counselors and therapists, and social workers. Map shows primary practice locations, but not density, of providers in Oregon.

Figure 2:

Spatial access to mental health providers, based on estimated drive time to the nearest provider. Notes: Distance to the nearest provider was assessed based on the estimated drive time between the centroid of a given ZCTA and the primary practice locations of prescribers and non-prescribers. Prescribers include psychiatrists, mental health nurse practitioners, and clinical nurse specialists; non-prescribers include psychologists, counselors and therapists, and social workers.

Figure 3:

Spatial access to mental health providers, based on enhanced two-step floating catchment area (E2SFCA) Notes: The E2SFCA approach generates Spatial Access Index (SPAI) scores that describe relative access in a given ZCTA, compared to all other ZCTAs in Oregon. Due to their relative nature, we present all E2SFCA results as percentiles. Higher values indicate relatively higher spatial access, and lower values indicate relatively lower spatial access. Prescribers include psychiatrists, mental health nurse practitioners, and clinical nurse specialists; non-prescribers include psychologists, counselors and therapists, and social workers.

Figure 4:

Comparison of spatial access (E2SFCA) to mental health prescribers versus non-prescribers across frontier, rural, and urban ZCTAs in Oregon. Notes: Each dot represents a single ZCTA. Frontier, rural, and urban classifications were specified by the Oregon Office of Rural Health. Spatial Access Index (SPAI) scores describe relative access in a given ZCTA, compared to all other ZCTAs in Oregon. Due to their relative nature, we present all E2SFCA results as percentiles. The plot shows SPAI percentiles for mental health prescribers (X-axis) and non-prescribers (Y-axis). Many Frontier ZCTAs have SPAI scores of zero for prescribers (Table S2), so they concentrate together along the 13th percentile line on the X-axis. Prescribers include psychiatrists, mental health nurse practitioners, and clinical nurse specialists; non-prescribers include psychologists, counselors and therapists, and social workers.