Table 3.

Discrimination performance of multivariable models to discriminate rejection and rejection phenotypes from the estimated cell composition

Metric Adjustment	Rejection versus No Rejection Discrimination		Rejection Phenotypes Discrimination
	Multivariable Logistic Regression Metric: AUC	Multivariable Logistic Regression+MFP Metric: AUC	Polytomous LR Including Non-Rejection Cases Metric: PDIa	Polytomous LR Excluding Non-Rejection Cases Metric: PDIb
Apparent performance (95% CI)	0.85 (0.82 to 0.89)	0.86 (0.82 to 0.89)	0.58 (0.53 to 0.63)	0.72 (0.64 to 0.80)
Corrected performance (95% CI)	0.84 (0.81 to 0.88)	0.83 (0.79 to 0.86)	0.52 (0.48 to 0.57)	0.63 (0.55 to 0.71)

Corrected pairwise AUCs (95% CI)
No rejection versus DSA-positive AMR			0.79 (0.74 to 0.84)	—
No rejection versus TCMR			0.90 (0.85 to 0.95)	—
No rejection versus DSA-positive mixed rejection			0.91 (0.86 to 0.96)	—
DSA-positive AMR versus TCMR			0.85 (0.78 to 0.92)	0.88 (0.78 to 0.91)
DSA-positive AMR versus DSA-positive mixed rejection			0.72 (0.63 to 0.81)	0.83 (0.66 to 0.84)
TCMR versus DSA-positive mixed			0.78 (0.68 to 0.88)	0.84 (0.67 to 0.88)

AMR, antibody-mediated rejection; AUC, area under the receiver operating characteristic curve; CI, confidence interval; DSA, donor-specific antibodies; LR, logistic regression; MFP, multivariable fractional polynomials; PDI, Polytomous Discrimination Index; TCMR, T-cell–mediated rejection.

^aBaseline Polytomous Discrimination Index: 0.25.

^bBaseline Polytomous Discrimination Index: 0.33.