Table 1.

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.