Demographic, treatment, and outcome characteristics of patients with and without severe immune-related adverse event (irAE)
| Patients without irAE | Patients with severe irAE | P value | |
| Number (%) | 13 874 (96.5%) | 504 (3.5%) | |
| Men (%) | 8172 (58.9%) | 298 (59.1%) | 0.96 |
| Women (%) | 5702 (41.1%) | 206 (40.9%) | 0.96 |
| Avg age (years) | 66.7 | 63.5 | <0.001 |
| Avg follow-up time (days) | 735.5 | 926.5 | <0.001 |
| Average time to hospitalization (days) | 172.0 | 148.7 | <0.001 |
| Immune checkpoint inhibitor use | |||
| PD-1 | 10 815 (78.0%) | 372 (73.8%) | 0.03 |
| PD-L1 | 1052 (7.6%) | 12 (2.4%) | <0.001 |
| CTLA-4 | 1022 (7.4%) | 42 (8.3%) | 0.47 |
| CTLA4/PD-1 or CTLA-4/PD-L1 combination | 985 (7.1%) | 78 (15.5%) | <0.001 |
| Average ICI treatment Length | 163.0 days | 168.2 days | 0.58 |
| Underlying conditions | |||
| Lung cancer | 7114 (51.3%) | 279 (55.4%) | 0.08 |
| Melanoma | 3036 (21.9%) | 121 (24.0%) | 0.28 |
| Renal cell carcinoma | 1430 (10.3%) | 56 (11.1%) | 0.61 |
| Other cancer | 2294 (16.5%) | 48 (9.5%) | <0.001 |
| Average Charlson Comorbidity Index | 1.5 | 1.5 | 0.90 |
| Secondary outcomes | |||
| Number of hospitalizations | 1 | 3.1 | <0.001 |
| Hospital length (days) | 3.1 | 6 | <0.001 |
| Proportion in ICU | 0.02 | 0.056 | <0.001 |
| Regional information | |||
| Average zip code unemployment | 0.06 | 0.06 | 0.33 |
| Average zip code income | 63 168.1 | 64 332.8 | 0.32 |
| East North Central | 2123 (15.3%) | 80 (15.9%) | 0.77 |
| East South Central | 445 (3.2%) | 14 (2.8%) | 0.68 |
| Mid-Atlantic | 3272 (23.6%) | 110 (21.8%) | 0.39 |
| Mountain | 626 (4.5%) | 24 (4.8%) | 0.88 |
| New England | 661 (4.8%) | 38 (7.5%) | 0.01 |
| Pacific | 1089 (7.8%) | 30 (6.0%) | 0.14 |
| South Atlantic | 3261 (23.5%) | 107 (21.2%) | 0.26 |
| West North Central | 470 (3.4%) | 25 (5.0%) | 0.08 |
| West South Central | 1927 (13.9%) | 76 (15.1%) | 0.49 |
Other cancers include: bladder cancer, colon cancer, head and neck squamous cell carcinoma Hodgkin’s lymphoma, gastric cancer, liver cancer, cervical cancer, and Merkel cell carcinoma.
CTLA-4, cytotoxic T lymphocyte-associated 4; ICI, immune checkpoint inhibitor; ICU, intensive care unit; PD-1, programmed cell death protein 1; PD-L1, programmed death-ligand 1.