1. Croft JB, Wheaton AG, Liu Y, Xu F, Lu H, Matthews KA, et al. Urban-rural county and state differences in chronic obstructive pulmonary disease—United States, 2015. MMWR Morb Mortal Wkly Rep. 2018;67(7):205–11.
2. Sullivan J, Pravosud V, Mannino DM, Siegel K, Choate R, Sullivan T. National and state estimates of COPD morbidity and mortality—United States, 2014–2015. Chronic Obstr Pulm Dis. 2018;5(4):324–33.
3. Kochanek KD, Murphy SL, Xu J, Arias E. Mortality in the United States, 2016 2017. https://www.cdc.gov/nchs/data/databriefs/db293.pdf.
4. Ford ES, Murphy LB, Khavjou O, Giles WH, Holt JB, Croft JB. Total and state-specific medical and absenteeism costs of COPD among adults aged ≥18 years in the United States for 2010 and projections through 2020. Chest. 2015;147(1):31–45.
5. Wallace AE, Kaila S, Bayer V, Shaikh A, Shinde MU, Willey VJ, et al. Health care resource utilization and exacerbation rates in patients with COPD stratified by disease severity in a commercially insured population. J Manag Care Spec Pharm. 2019;25(2):205–17.