Table 4. Multivariable survival analysis of OS main effect.

Covariate	Level	N	Overall survival (months)
			Hazard ratio (95% CI)	HR P value	Type 3 P value
Received local therapy	Yes	948	0.66 (0.55–0.79)	<0.001	<0.001
	No	212	Reference	–
Sequence of chemo and local therapy	During chemo	416	0.77 (0.63–0.94)	0.011	<0.001
	After chemo	274	0.72 (0.58–0.89)	0.003
	Unknown	252	1.15 (0.93–1.43)	0.199
	Before chemo	218	Reference	–
Age at diagnosis, years	>70	146	1.28 (1.02–1.61)	0.036	0.111
	60–70	328	1.08 (0.91–1.28)	0.404
	<60	686	Reference	–
Sex	Male	407	1.46 (1.26–1.70)	<0.001	<0.001
	Female	753	Reference	–
Primary payor	Not insured	109	1.33 (1.03–1.72)	0.030	0.007
	Medicaid/Medicare/Other Government	501	1.29 (1.09–1.53)	0.002
	Unknown	21	0.85 (0.49–1.48)	0.569
	Private	529	Reference	–
Year of diagnosis	≥2004, ≤2008	317	1.09 (0.83–1.42)	0.543	0.007
	>2008, ≤2011	286	0.86 (0.66–1.13)	0.292
	>2011, ≤2014	405	0.80 (0.61–1.04)	0.099
	>2014, ≤2015	152	Reference	–
Primary site	C218-Overlapping lesion of rectum/anal canal	156	0.93 (0.75–1.16)	0.525	0.030
	C212-Cloacogenic zone	4	4.47 (1.58–12.62)	0.005
	C211-Anal canal	502	0.95 (0.82–1.11)	0.525
	C210-Anus, NOS	498	Reference	–
Grade	Well differentiated, differentiated, NOS	35	1.06 (0.69–1.61)	0.799	0.075
	Moderately differentiated	394	0.83 (0.70–0.98)	0.031
	Cell type not determined, not stated	294	0.82 (0.69–0.99)	0.040
	Poorly differentiated/anaplastic	437	Reference	–
Charlson-Deyo Score	2+	72	1.10 (0.82–1.48)	0.536	0.181
	1	118	1.24 (0.98–1.57)	0.075
	0	970	Reference	–

Number of observations in the original data set =1,160. Number of observations used =1,160. Backward selection with an alpha level of removal of .20 was used. The following variables were removed from the model: Histology, Median Income Quartiles 2000, TUMOR_SIZE_AllYear, Urban/Rural 2003, Race, and Surgical Margins.