Table 4.

Comparison of models based on discrimination, calibration, and reclassification measures

Models	Discrimination C-Indexa	Goodness-of-Fit, Likelihood Ratio X2 (p value)b	Calibration Cox X2c	NRId (p value)	IDIe (p value)	Percent reclassifiedf
Non-lipid covariates and total/HDL cholesterol ratio (referent model)	0.784	Referent	16.7	Referent	Referent	Referent
Referent model covariates plus LDLNMR	0.785	2.01 (0.16)	17.2	0% (0.52)	0.0% (0.65)	1.1
Referent model covariates plus apolipoprotein B100	0.786	10.5 (0.001)	14.3	1.9% (0.02)	0.1% (0.12)	2.6

All statistical measures were calculated at 10-years of follow-up.

^aThe c-index for the referent model (non-lipid covariates and total/HDL cholesterol ratio) was not statistically significantly different from the models that additionally included LDL_NMR or apolipoprotein B₁₀₀.

^bValues are likelihood ratio X² and p values obtained from the Cox proportional hazards regression comparing models that added either LDL_NMR or apolipoprotein B₁₀₀ to the referent model (non-lipid covariates and total/HDL cholesterol ratio). A higher X² value indicates a better model fit.

^cValues are modified Hosmer-Lemeshow X², comparing differences between the predicted and actual event rates (X² values greater than 20 indicate poor calibration).¹⁹

^dNRI is the net reclassification index, which compares the proportions moving up or down in clinical categories in cases versus controls, comparing models that added either LDL_NMR or apolipoprotein B₁₀₀ to the referent model.

^eIDI is the integrated discrimination improvement, comparing the integrals of sensitivity and specificity under two models (referent model compared with the model that added either LDL_NMR or apolipoprotein B₁₀₀).

^fThe proportion of individuals that move up or down a risk category using the model that incorporates either LDL_NMR or apolipoprotein B₁₀₀ compared with the referent model.