Baseline demographics of the study population.
| Demographics | Patient-Reported Penicillin Allergy (n = 7497) | No Penicillin Allergy (n = 278,545) | P Value |
| Age, y | 0.410 | ||
| <65 | 1662 (22.2%) | 63,023 (22.6%) | |
| 65–69 | 2025 (27.0%) | 76,403 (27.4%) | |
| 70–74 | 1751 (23.4%) | 63,639 (22.8%) | |
| 75–79 | 1233 (16.4%) | 44,822 (16.1%) | |
| 80–84 | 598 (8.0%) | 21,402 (7.7%) | |
| ≥85 | 164 (2.2%) | 6355 (2.3%) | |
| Gender | <0.001 | ||
| Male | 2041 (27.2%) | 105,212 (37.8%) | |
| Female | 5392 (71.9%) | 170,432 (61.2%) | |
| Unknown | 64 (0.9%) | 2901 (1.0%) | |
| Region | <0.001 | ||
| Midwest | 1463 (19.5%) | 72,523 (26.0%) | |
| Northeast | 792 (10.6%) | 36,314 (13.0%) | |
| South | 3673 (49.0%) | 122,287 (43.9%) | |
| West | 1567 (20.9%) | 47,406 (17.0%) | |
| Unknown | 2 (<0.1%) | 15 (<0.1%) | |
| Elixhauser Comorbidity Index, mean ± SD | 4.9 ± 2.0 | 4.7 ± 2.0 | <0.001 |
Note: Data presented as n (%) unless otherwise noted.