Table 2.

Inverse Probability Weighting (IPW)-Adjusted Logistic Regression Analysis to Assess the Associations of Fusobacterium nucleatum (Predictor) with T Cell Density (Outcome)

	Univariable OR (95% CI)*	Multivariable OR (95% CI)*,†
Model for stromal CD3+ cell density (as an ordinal outcome variable)
Amount of F. nucleatum DNA
Negative	1 (referent)	1 (referent)
Low	0.54 (0.33–0.91)	0.51 (0.30–0.87)
High	0.51 (0.30–0.84)	0.47 (0.28–0.79)
Ptrend‡	0.001	0.0004
Model for stromal CD3+CD4+ cell density (as a binary outcome variable)
Amount of F. nucleatum DNA
Negative	1 (referent)	1 (referent)
Low	0.86 (0.49–1.48)	0.80 (0.46–1.39)
High	0.52 (0.29–0.91)	0.50 (0.28–0.89)
Ptrend§	0.023	0.015
Model for stromal CD3+CD4+CD45RO+ cell density (as an ordinal outcome variable)
Amount of F. nucleatum DNA
Negative	1 (referent)	1 (referent)
Low	0.66 (0.40–1.09)	0.67 (0.41–1.10)
High	0.53 (0.33–0.85)	0.52 (0.32–0.85)
Ptrend‡	0.003	0.003
Model for stromal CD3+CD4+CD45RO− cell density (as an ordinal outcome variable)
Amount of F. nucleatum DNA
Negative	1 (referent)	1 (referent)
Low	0.73 (0.43–1.25)	0.74 (0.43–1.28)
High	0.75 (0.47–1.17)	0.75 (0.47–1.17)
Ptrend‡	0.12	0.13

^*IPW was applied to reduce a bias due to the availability of tumor tissue after cancer diagnosis (see “Statistical Analysis” subsection for details).

^†The multivariable ordinal logistic regression model initially included age, sex, year of diagnosis, family history of colorectal cancer, tumor location, microsatellite instability, CpG island methylator phenotype, long-interspersed nucleotide element-1 methylation level, and KRAS, BRAF, and PIK3CA mutation status. A backward elimination with a threshold P of 0.20 was used to select variables for the final model. The variables which remained in the final models are shown in Supplementary Table S2.

^‡P_trend was calculated by the linear trend across the ordinal categories of F. nucleatum DNA amount (negative, low, and high, as an ordinal predictor variable) in the IPW-adjusted ordinal logistic regression model for the densities of T cells (4 ordinal categories, as an ordinal outcome variable).

^§To avoid violation of the proportional odds assumption, the density of CD3⁺CD4⁺ cell was dichotomized at the median value of subset. P_trend was calculated by the linear trend across the ordinal categories of F. nucleatum DNA amount (negative, low, and high, as an ordinal predictor variable) in the IPW-adjusted logistic regression model for the density of CD3⁺CD4⁺ cell (binary categories, as an outcome variable).

Abbreviations: CI, confidence interval; IPW, inverse probability weighting; OR, odds ratio.