Covariates for analysis were selected from the literature.18 Diagnosis groups were classified according to Lung Allocation Score guidelines27 and included groups A (primarily obstructive lung diseases, eg, chronic obstructive pulmonary disease), B (primarily pulmonary vascular diseases, eg, pulmonary hypertension), C (cystic fibrosis or immunodeficiency disorders), and D (primarily restrictive lung diseases, eg, idiopathic pulmonary fibrosis). Organ Procurement and Transplantation Network regions were categorized as 1 (Connecticut, Maine, Massachusetts, New Hampshire, and Rhode Island); 2 (Delaware; Maryland; New Jersey; Pennsylvania; Washington, DC; and West Virginia); 3 (Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, and Puerto Rico); 4 (Oklahoma and Texas); 5 (Arizona, California, Nevada, New Mexico, and Utah); 6 (Alaska, Hawaii, Idaho, Montana, Oregon, and Washington); 7 (Illinois, Minnesota, North Dakota, South Dakota, and Wisconsin); 8 (Colorado, Iowa, Kansas, Missouri, Nebraska, and Wyoming); 9 (New York and Vermont); 10 (Indiana, Michigan, and Ohio); and 11 (Kentucky, North Carolina, South Carolina, Tennessee, and Virginia). Donor cytomegalovirus status was defined by cytomegalovirus serologic test results at the time of organ donation. Health insurance type was categorized as either private or nonprivate (including Medicaid, Medicare, US Department of Veterans Affairs, self-pay, and donated or free care). To evaluate neighborhood-level socioeconomic status, we used 2000 US Census Bureau28 data to obtain median household income in each patient's residential zip code.