Quantifying transportation shortages and using geomapping to assess risk of transportation barriers to health care access

Geospatial access and transportation availability are important factors in child health care access. Nationally, 4% of children (9% with household incomes <$0,000) missed at least one health care appointment annually because transportation was not available. One-third later used a hospital emergency department. We developed and validated a tool, the Health Transportation Shortage Index (HTSI) to identify areas where transportation is a health care access barrier. In this study we computed a HTSI score for each county in Mississippi and Michigan to quantify risk. We geomapped each county, locating every federally qualified health center and rural health clinic (“clinic”) within the county. Euclidian distances to nearest clinic (including those in contiguous counties) were computed using geographic- and population-weighted centroids as starting points. A HTSI cut score was determined that correctly identified 75.2% of counties with 1 or 0 pediatricians and correspondingly few family practitioners (p<0.01); 87.0% of these counties had populations <30,000 (p<0.01); 78.8% had the highest poverty rates in their state (p<0.01); 76.4% had no fixed route transit system including 17.6% with no public transit resources (p<0.01). Population-weighted analysis best reflected travel distances. Geomapping revealed that clinic resources are well-located relative to population centers, with mean travel distances generally <7 miles for the county. The longest travel distances were in the most rural counties (p<0.01). Some rural residential areas were 20-34 miles from the nearest clinic, underscoring the importance of transportation to facilitate access. Supplementing HTSI scores with geomapping facilitates health planning for new health care and/or transit resources.