Transportation barriers, emergency room use, and mortality risk among US adults by cancer history

Background: Lack of safe, reliable, and affordable transportation is a barrier to medical care, but little is known about its association with clinical outcomes. Methods: We identified 28 640 adults with and 470 024 adults without a cancer history from a nationally representative cohort (2000- 2018 US National Health Interview Survey) and its linked mortality files with vital status through December 31, 2019. Transportation barriers were defined as delays in care because of lack of transportation. Multivariable logistic and Cox proportional hazards models estimated the associations of transportation barriers with emergency room (ER) use and mortality risk, respectively, adjusted for age, sex, race and ethnicity, education, health insurance, comorbidities, functional limitations, and region. Results: Of the adults, 2.8% (n=988) and 1.7% (n=9685) with and without a cancer history, respectively, reported transportation barriers; 7324 and 40 793 deaths occurred in adults with and without cancer history, respectively. Adults with a cancer history and transportation barriers, as compared with adults without a cancer history or transportation barriers, had the highest likelihood of ER use (adjusted odds ratio [aOR] = 2.77, 95% confidence interval [CI] = 2.34 to 3.27) and all-cause mortality risk (adjusted hazard ratio [aHR] = 2.28, 95% CI = 1.94 to 2.68), followed by adults without a cancer history with transportation barriers (ER use aOR=1.98, 95% CI =1.87 to 2.10; all-cause mortality aHR = 1.57, 95% CI = 1.46 to 1.70) and adults with a cancer history but without transportation barriers (ER use aOR=1.39, 95% CI = 1.34 to 1.44; all-cause mortality aHR = 1.59, 95% CI = 1.54 to 1.65). Conclusion: Delayed care because of lack of transportation was associated with increased ER use and mortality risk among adults with and without cancer history. Cancer survivors with transportation barriers had the highest risk.