Table 2.

Comparison of nested models determining the hazard ratio of statin use on survival

	Base model		Extended model
Measure of comorbidity	HR (95% CI)	c-statistic	HR (95% CI)	c-statistic†	Change in c-statistic
Overall survival
Charlson score	0.87 (0.63–1.22)	0.748 (0.720–0.792)	0.92 (0.66–1.28)	0.761 (0.733–0.806)	0.013 (0.004–0.030)
John Hopkins ADG score	0.90 (0.65–1.26)	0.734 (0.694–0.782)	0.93 (0.66–1.29)	0.748 (0.719–0.797)	0.014 (0.005–0.034)
Cancer-specific survival
Charlson score	0.63 (0.30–1.31)	0.765 (0.716–0.842)	0.63 (0.30–1.31)	0.778 (0.747–0.856)	0.012 (0.004–0.069)
John Hopkins ADG score	0.62 (0.30–1.29)	0.765 (0.715–0.838)	0.61 (0.29–1.27)	0.781 (0.741–0.854)	0.016 (0.006–0.069)

^†Based on predicting five-year survival.

ADG: aggregated diagnosis groups; CI: confidence interval; HR: hazard ratio.