Table 2.

Hazard Ratios for Death with Adjustment for Stage of Disease and Other Variables, According to Tumor PIK3CA Mutation Status and Use or Nonuse of Aspirin after Diagnosis.^*

PIK3CA	Total No. of Patients	Colorectal Cancer–Specific Mortality							Overall Mortality
		No. of Deaths	Univariate Hazard Ratio (95% CI)	P Value†	Hazard Ratio, Adjusted for Disease Stage (95% CI)	P Value†	Multivariate Hazard Ratio, Adjusted for Disease Stage (95% CI)	P Value†	No. of Deaths	Univariate Hazard Ratio (95% CI)	P Value†	Hazard Ratio, Adjusted for Disease Stage (95% CI)	P Value†	Multivariate Hazard Ratio, Adjusted for Disease Stage (95% CI)	P Value†
Wild-type				0.003		0.01		0.009			0.02		0.06		0.07
No aspirin use	466	96	1.00 (referent)		1.00 (referent)		1.00 (referent)		196	1.00 (referent)		1.00 (referent)		1.00 (referent)
Aspirin use	337	65	0.95 (0.69–1.30)		0.93 (0.68–1.28)		0.96 (0.69–1.32)		137	1.01 (0.81–1.25)		1.01 (0.81–1.25)		0.94 (0.75–1.17)
Mutant
No aspirin use	95	26	1.00 (referent)		1.00 (referent)		1.00 (referent)		44	1.00 (referent)		1.00 (referent)		1.00 (referent)
Aspirin use	66	3	0.14 (0.04–0.47)		0.18 (0.05–0.60)		0.18 (0.06–0.61)		18	0.49 (0.28–0.85)		0.57 (0.33–0.98)		0.54 (0.31–0.94)

^*The multivariate Cox regression model, stratified according to and adjusted for disease stage, initially included age, sex, year of diagnosis, time from diagnosis to first measurement of aspirin use after diagnosis (in months), regular use or nonuse of aspirin before diagnosis, tumor location, tumor differentiation, body-mass index, microsatellite instability status, CpG island methylator phenotype, KRAS mutation, BRAF mutation, LINE-1 (long interspersed nucleotide element-1) methylation, and the presence or absence of PTGS2 expression. A backward-elimination model with a threshold of P = 0.05 was used to select variables in the final models. CI denotes confidence interval.

^†P values are for the interaction of aspirin use and PIK3CA mutation.