Table 3.

Results of Cox proportional hazard models

Class	Model I		Model II
	HR (95% CI)	P value	HR (95% CI)	P value
Class 1	Reference		Reference
Class 2	1.925 (1.522–2.432)	< 0.001	1.914 (1.503–2.437)	< 0.001
Class 3	0.394 (0.271–0.575)	< 0.001	0.338 (0.228–0.502)	< 0.001
Class 4	0.698 (0.563–0.866)	0.001	0.677 (0.545–0.841)	< 0.001
Class 5	0.939 (0.753–1.172)	0.579	0.897 (0.718–1.121)	0.340
Class 6	0.494 (0.346–0.705)	< 0.001	0.614 (0.428–0.879)	0.008
Class 7	0.467 (0.240–0.907)	0.025	0.668 (0.341–1.309)	0.240