Table 5.

Hazard ratios for stage IV colon cancer patients who received KRAS testing: right vs. left, diagnosis years 2010–12. (Excluded rectal cancer patients)

		Right-sided (N=1,930)	Left-sided (N=2,064)
		Adjusted HR* (95% CI)	Adjusted HR* (95% CI)
KRAS Tested:	Normal	1.00 [Referent]	1.00 [Referent]
	Mutated	0.93 (0.83, 1.03)	1.18 (1.05, 1.33)
Age (y):	0–29	1.00 [Referent]	1.00 [Referent]
	30–39	0.88 (0.41, 1.89)	1.09 (0.64, 1.87)
	40–49	0.91 (0.44, 1.87)	1.14 (0.69, 1.90)
	50–59	1.06 (0.52, 2.15)	1.40 (0.85, 2.30)
	60–69	1.29 (0.63, 2.62)	1.51 (0.92, 2.49)
	70–79	1.44 (0.71, 2.93)	1.93 (1.16, 3.22)
	80+	2.17 (1.05, 4.45)	2.94 (1.72, 5.01)
Race:	White	1.00 [Referent]	1.00 [Referent]
	Black	0.98 (0.85, 1.15)	1.39 (1.18, 1.63)
	Other	0.81 (0.64, 1.03)	0.88 (0.73, 1.06)
Diagnosis Year:	2010	1.00 [Referent]	1.00 [Referent]
	2011	0.89 (0.79, 1.02)	1.03 (0.89, 1.18)
	2012	0.84 (0.73, 0.97)	1.01 (0.86, 1.18)
Insurance:	Private/Medicare	1.00 [Referent]	1.00 [Referent]
	Medicaid	1.18 (0.99, 1.40)	1.26 (1.07, 1.47)
	Uninsured	1.32 (0.99, 1.75)	1.34 (1.04, 1.73)
	Unknown	1.11 (0.66, 1.87)	1.21 (0.79, 1.86)
Marital status:	Married	1.00 [Referent]	1.00 [Referent]
	Divorced/separated	1.05 (0.88, 1.25)	1.05 (0.87, 1.26)
	Widowed	1.18 (1.00, 1.39)	1.24 (1.00, 1.54)
	Single/never married	1.23 (1.05, 1.45)	1.24 (1.06, 1.44)
	Unknown	0.93 (0.68, 1.29)	0.87 (0.62, 1.22)
Grade:	Well (I) differentiated	1.00 [Referent]	1.00 [Referent]
	Moderately (II) differentiated	0.96 (0.70, 1.32)	1.26 (0.95, 1.68)
	Poorly (III) differentiated	1.40 (1.02, 1.93)	2.05 (1.51, 2.78)
	Undifferentiated (IV)	1.51 (1.03, 2.21)	2.14 (1.42, 3.23)
	Unknown	1.21 (0.86, 1.70)	1.31 (0.96, 1.79)
T Stage:	≤ T3	1.00 [Referent]	1.00 [Referent]
	≥ T4a	1.24 (1.10, 1.41)	1.22 (1.07, 1.40)
	TX (Unknown)	1.05 (0.86, 1.28)	1.10 (0.92, 1.32)
N Stage:	N0	1.00 [Referent]	1.00 [Referent]
	≥ N1a	1.14 (0.98, 1.32)	1.08 (0.93, 1.25)
	NX (Unknown)	1.24 (0.98, 1.58)	1.25 (1.01, 1.55)
M Stage:**	M1a	1.00 [Referent]	1.00 [Referent]
	M1b	1.28 (1.14, 1.44)	1.53 (1.35, 1.74)
	M1NOS	0.99 (0.69, 1.42)	1.66 (1.21, 2.29)
Surgery:	Yes	0.53 (0.45, 0.64)	0.49 (0.42, 0.58)
	No or Unknown	1.00 [Referent]	1.00 [Referent]

^*Manual backward selection was used to retain variables significant at p <0.05, except the following which were forced into all models: KRAS results, age, registry, race, diagnosis year, insurance, marital status, T stage, N stage, & M stage.

^**Due to small numbers, metastatic sites were not included in Right- and Left-sided models; overall M stage was used instead.