Chemotherapy predictors and a time-dependent chemotherapy effect in metastatic esophageal cancer

Table 2 Univariate and multivariable analyses of factors associated with receipt of chemotherapy vs no chemotherapy in advanced esophageal cancer patients

Variable		Univariate		Multivariable1
	n	Odds ratio (95%CI)	P value	Odds ratio (95%CI)	P value
Age	29182	0.96 (0.95-0.96)	< 0.001	0.95 (0.94-0.96)	< 0.001
Gender
Female	5126	0.71 (0.67-0.76)	< 0.001	0.86 (0.76-0.98)	0.019
Male	24056	1 (reference)		1 (reference)
Race (combined)
Black	2878	0.64 (0.59-0.70)	< 0.001	0.79 (0.67-0.93)	0.005
Other	1669	0.92 (0.82-1.03)	0.148	1.12 (0.89-1.40)	0.322
White	24389	1 (reference)		1 (reference)
Insurance type
Medicaid	2415	0.48 (0.44-0.54)	< 0.001	0.52 (0.43-0.64)	< 0.001
Medicare	13412	0.41 (0.38-0.44)	< 0.001	0.84 (0.73-0.97)	0.017
Other government	459	0.43 (0.35-0.53)	< 0.001	0.74 (0.50-1.09)	0.123
Not insured	1404	0.39 (0.35-0.45)	< 0.001	0.41 (0.33-0.52)	< 0.001
Private	10923	1 (reference)		1 (reference)
Income quartiles for place of residence
Less than $30000	3918	1 (reference)		1 (reference)
$30000-$34999	5362	1.27 (1.16-1.39)	< 0.001	1.12 (0.95-1.33)	0.172
$35000-$45999	8066	1.40 (1.29-1.53)	< 0.001	1.31 (1.12-1.54)	0.001
$46000+	10652	1.61 (1.49-1.75)	< 0.001	1.49 (1.27-1.75)	< 0.001
Treatment site
Academic	12955	1.12 (1.06-1.18)	< 0.001	Dropped out of the model
Non-academic	15786	1 (reference)
Geographic location in United States
Northeast	6772	1.28 (1.17-1.40)	< 0.001	1.45 (1.22-1.72)	< 0.001
Midwest	8278	1.33 (1.23-1.45)	< 0.001	1.43 (1.22-1.68)	< 0.001
South	9509	1.09 (1.00-1.18)	0.044	1.22 (1.04-1.43)	0.015
West	4182	1 (reference)		1 (reference)
Residence area type
Metro	22465	1.13 (0.94-1.34)	0.185	Dropped out of the model
Urban	4921	1.12 (0.93-1.34)	0.248
Rural	641	1 (reference)
Number of comorbidities2
1	5401	0.69 (0.65-0.74)	< 0.001	0.79 (0.70-0.90)	< 0.001
≥ 2	1772	0.49 (0.44-0.54)	< 0.001	0.61 (0.50-0.74)	< 0.001
0	22009	1 (reference)		1 (reference)
Year of diagnosis
2010-2014	13467	1.17 (1.11-1.23)	< 0.001	1.29 (1.17-1.43)	< 0.001
2004-2009	15715	1 (reference)		1 (reference)
Grade3
1	633	1 (reference)		1 (reference)
2	7926	1.11 (0.92-1.34)	0.273	1.08 (0.78-1.48)	0.648
3	13849	1.04 (0.87-1.25)	0.664	0.96 (0.70-1.31)	0.786
4	467	0.92 (0.70-1.21)	0.550	0.69 (0.44-1.08)	0.105
AJCC T stage
pIS	10	1.65 (0.35-7.80)	0.525	20075.87 (0.00-NA)	0.948
T0	51	0.64 (0.36-1.13)	0.123	0.63 (0.29-1.40)	0.261
T1	2624	1.06 (0.96-1.18)	0.262	1.10 (0.96-1.27)	0.181
T2	1751	1.93 (1.68-2.22)	< 0.001	1.87 (1.56-2.25)	< 0.001
T3	7128	2.47 (2.25-2.71)	< 0.001	2.29 (2.03-2.59)	< 0.001
T4	4570	1 (reference)		1 (reference)
AJCC N stage
Positive	17435	1.59 (1.48-1.71)	< 0.001	1.35 (1.20-1.52)	< 0.001
Negative	4983	1 (reference)		1 (reference)

¹10799 complete observations were used in the multivariable model.

²Per Charlson/Deyo[11].

³Grade 1, well-differentiated; grade 2, moderately differentiated; grade 3, poorly differentiated; grade 4, undifferentiated.

AJCC: American Joint Committee on Cancer; CI: Confidence interval; NA: Not available.