Table 5.

The Amount of Bifidobacterium DNA in Colorectal Cancer Tissue and Patient Survival with Inverse Probability Weighting

Variable	Cases, n	Colorectal cancer–specific survival			Overall survival
		Events, n	Univariable HR (95% CI)∗	Multivariable HR (95% CI)∗†	Events, n	Univariable HR (95% CI)∗	Multivariable HR (95% CI)∗†
Amount of Bifidobacterium DNA in colorectal cancer tissue
Negative	893	252	1 (referent)	1 (referent)	531	1 (referent)	1 (referent)
Low	189	50	1.00 (0.72–1.37)	0.99 (0.72–1.35)	116	1.04 (0.84–1.30)	1.01 (0.81–1.26)
High	188	54	0.93 (0.67–1.29)	0.93 (0.66–1.32)	107	0.90 (0.70–1.15)	0.90 (0.71–1.15)
Ptrend‡			0.70	0.71		0.51	0.48

HR, hazard ratio.

^∗Inverse probability weighting was applied to reduce a bias attributable to the availability of tumor tissue after cancer diagnosis (Statistical Analysis).

^†The multivariable Cox regression model initially included sex, age, year of diagnosis, family history of colorectal cancer, tumor location, tumor differentiation, disease stage, microsatellite instability, CpG island methylator phenotype, KRAS, BRAF, and PIK3CA mutations, and long-interspersed nucleotide element-1 methylation level. A backward elimination with a threshold P of 0.05 was used to select variables for the final models.

^‡P_trend value was calculated across the ordinal categories (negative, low, and high) of the amount of Bifidobacterium DNA in colorectal cancer tissue in the inverse probability weighting–adjusted Cox regression model.