Geographic Access to CT for Lung Cancer Screening: A Census Tract-Level Analysis of Cigarette Smoking in the United States and Driving Distance to a CT Facility

Purpose

Spatial access to health care resources is a requisite for utilization. Our purpose was to determine, at a census tract level, the geographic distribution of US smokers and their driving distance to an ACR-accredited CT facility.

Methods

The number of smokers per US census tract was determined from US Census Bureau data (American Community Survey, 2011-2015) and census tract smoking prevalence estimates. Driving distance, from the centroid of each census tract to the nearest CT facility, was determined using a geographic information system. Distance variations were assessed, and relationships with tract population density were examined with regression models.

Results

Most US smokers (81.8%) were within 15 miles of a CT facility; however, there was considerable inter- and intrastate variability. For census tracts containing ≥500 smokers, median distance to a CT was 4.3 miles. At the state level, median distance ranged from 1.4 (Washington DC) to 29.1 miles (Wyoming). Within each state, this variation was higher, with Washington, DC, exhibiting the lowest range (range, 4.3; 0.2-4.5 miles) and Maine exhibiting the highest range (range, 244.8; 0.2-245.0 miles). Distance to a CT facility was inversely associated with census tract population density.

Conclusions

Geographic variability in CT facility access has implications for lung cancer screening (LCS) implementation. Individuals in densely populated areas have relatively greater spatial access to CT facilities than those in sparsely populated tracts. Further work is needed to identify access disparities to LCS to optimize LCS for all eligible populations.