Volume 55 | Number 3 | June 2020

Abstract List

Sean G. Young PhD, Thomas S. Gruca, Gregory C. Nelson MA, RN


To assess the impact of nonphysician providers on measures of spatial access to primary care in Iowa, a state where physician assistants and advanced practice registered nurses are considered primary care providers.

Data Sources

2017 Iowa Health Professions Inventory (Carver College of Medicine), and minor civil division (MCD) level population data for Iowa from the American Community Survey.

Study Design

We used a constrained optimization model to probabilistically allocate patient populations to nearby (within a 30‐minute drive) primary care providers. We compared the results (across 10 000 scenarios) using only primary care physicians with those including nonphysician providers (NPPs). We analyze results by rurality and compare findings with current health professional shortage areas.

Data Collection/Extraction Methods

Physicians and NPPs practicing in primary care in 2017 were extracted from the Iowa Health Professions Inventory.

Principal Findings

Considering only primary care physicians, the average unallocated population for primary care was 222 109 (7 percent of Iowa's population). Most of the unallocated population (86 percent) was in rural areas with low population density (< 50/square mile). The addition of NPPs to the primary care workforce reduced unallocated population by 65 percent to 78 252 (2.5 percent of Iowa's population). Despite the majority of NPPs being located in urban areas, most of the improvement in spatial accessibility (78 percent) is associated with sparsely populated rural areas.


The inclusion of nonphysician providers greatly reduces but does not eliminate all areas of inadequate spatial access to primary care.