Table 1.

Baseline patient characteristics of the stage IV lung cancer SEER-Medicare cohort (n = 102 929)

Patient characteristics	All patients No.	Prior malignancy No. (%)	P*	Adjusted P†
Age, y			<.001	.74
<75	46 258	5622 (12.2)
75–85	44 745	7496 (16.8)
≥85	11 926	2052 (17.2)
Sex			<.001	.95
Female	46 706	5749 (12.3)
Male	56 223	9421 (16.8)
Race			<.001	.95
White	87 800	13 219 (15.1)
Black	8896	1295 (14.6)
Other	5025	517 (10.3)
Hispanic	1208	139 (11.5)
Marital status			<.001	.93
Married	51 186	8224 (16.1)
Sep/div/wid‡	40 390	5526 (13.7)
Single	7970	954 (12.0)
Unknown	3383	466 (13.8)
Histology			<.001	.89
Adenocarcinoma	32 346	5031 (15.6)
Squamous	14 952	2342 (15.7)
Small cell	17 977	2410 (13.4)
NSCLC§	37 654	5387 (14.3)
Charlson Comorbidity Score			<.001	.94
0	36 485	5345 (14.6)
1	31 651	4643 (14.7)
2+	31 477	4866 (15.5)
Not available	3316	316 (9.5)
Medicaid			<.001	.10
Yes	18 678	2026 (10.8)
No	84 251	13 144 (15.6)
Lung cancer treatment			<.001	.33
Surgery only	1353	235 (17.4)
Chemotherapy only	13 949	2257 (16.2)
Radiation only	21 573	3251 (15.1)
≥2 treatments	22 231	3227 (14.5)
No surg/chemo/rad||	43 823	6200 (14.1)
Cause of death#			<.001
Alive	4743	789 (16.6)
Lung cancer specific	82 007	10 650 (13.0)
All other causes	16 179	3731 (23.1)
Total
	102 929	15 170 (14.7)

* Two-sided P value was calculated from logistic model Wald Chi-square. NSCLC = non–small cell lung cancer; SEER = Surveillance, Epidemiology, and Ends Results.

† Two-sided propensity score–adjusted P value: Groups are well balanced for covariables of interest if P values are not statistically significant.

‡ Separated/divorced/widowed.

§ Non–small cell lung carcinoma.

|| No surgery/chemotherapy/radiation.

# Dependent variable, no adjusted P value necessary.