Total study cohort characteristics.
| Characteristics | Total Patients(N = 35,199) |
| Age, y, mean (SD) | 78.7 (11.1) |
| Sex, female, n (%) | 28,902 (82.1) |
| Race, n (%) | |
| White/Caucasian | 28,901 (82.1) |
| Black/African American | 869 (2.5) |
| Hispanic/Latino | 1885 (5.4) |
| Asian/Pacific Islander | 1063 (3.0) |
| Native American | 118 (0.3) |
| Unknown/other | 653 (1.9) |
| Insurance coverage, n (%) | |
| Medicare | 30,732 (87.3) |
| Medicaid | 1033 (2.9) |
| Private insurance | 2851 (8.1) |
| Self-pay | 225 (0.6) |
| No charge | 20 (0.1) |
| Other | 327 (0.9) |
| Income quartile, n (%) | |
| First (poorest) | 7569 (21.5) |
| Second | 9067 (25.8) |
| Third | 9121 (25.9) |
| Fourth (wealthiest) | 8908 (25.3) |
| Hospital location/teaching status, n (%) | |
| Rural | 3907 (11.1) |
| Urban, nonteaching | 12,116 (34.4) |
| Urban, teaching | 19,176 (54.5) |
| Hospital control, n (%) | |
| Public | 2981 (8.5) |
| Private, nonprofit | 28,321 (80.5) |
| Private, for-profit | 3897 (11.1) |
| Geographical region, n (%) | |
| Northeast | 7240 (20.6) |
| Midwest | 9474 (26.9) |
| South | 10,427 (29.6) |
| West | 8058 (22.9) |