Table 3.

Adjusted analysis for factors associated with immunotherapy use.

Factors associated with immunotherapy use	Adjusted hazard ratio of immunotherapy treatment vs. no IO treatment (95% CI)
	Unit	N in category	HR	Lower CL	Upper CL	P value
Age	Every additional 10 years		0.91	0.89	0.93	<.0001
Sex	Reference = “Male”	24 756	0.85	0.81	0.89	<.0001
Income quintile	Reference = “Quintile 5”
	Quintile 1	13 606	0.85	0.80	0.91	<.0001
	Quintile 2	12 964	0.91	0.85	0.98	.007
	Quintile 3	11 652	0.97	0.91	1.04	.338
	Quintile 4	10 886	0.96	0.89	1.02	.186
	Missing	189	0.92	0.46	1.84	.811
Rural	Reference = “Urban”
	Rural	8845	1.02	0.95	1.09	.620
	Missing	80	0.94	0.39	2.25	.890
Year of cohort entry	per year		1.78	1.75	1.80	<.0001
LHIN	Ref = G
	A	3813	1.10	0.98	1.25	.110
	B	5238	1.11	0.99	1.25	.072
	C	3151	1.07	0.94	1.22	.302
	D	7321	1.18	1.06	1.31	.002
	E	2448	1.23	1.08	1.39	.002
	F	3512	1.10	0.90	1.14	.888
	H	5870	1.02	0.92	1.14	.677
	I	6692	1.22	1.10	1.36	.000
	J	3401	1.31	1.16	1.48	<.0001
	K	6280	1.15	1.03	1.28	.012
	L	2513	1.30	1.14	1.49	.000
	M	3814	1.19	1.05	1.35	.007
	N	1231	0.86	0.71	1.04	.119
Tumor site	Per site (reference melanoma)
	Lung	41 324	0.45	0.42	0.48	<.0001
	Kidney	3387	0.54	0.50	0.59	<.0001
	HNC	7253	0.08	0.08	0.09	<.0001
	Bladder	3708	0.30	0.27	0.33	<.0001
More than one (stage 4) cancer diagnosis	Yes vs. no	537	0.88	0.62	1.25	.471
Diagnosing cancer center level	Ref = (level 1)	19 769
	2	15 078	1.12	1.05	1.20	.001
	3	14 221	1.06	0.99	1.13	.109
	4	10 386	0.95	0.89	1.02	.138
	Missing	56	1.21	0.78	1.90	.397
Charlson score	Ref = 0
	No hosp	37 492	0.96	0.87	1.06	.414
	1	7857	0.86	0.77	0.95	.005
	2	4961	0.84	0.76	0.94	.002
	3+	3891	1.01	0.95	1.08	.692
Hospitalization	yes vs. no	40 459	0.78	0.75	0.82	<.0001
Radiation therapy	yes vs no	33 892	1.55	1.48	1.62	<.0001
De novo stage 4 cancer	yes vs no	43 297	0.80	0.77	0.84	<.0001

Abbreviation: IO, immunotherapy.