Table 2.

The time-dependent Cox proportional hazard model.

Model	Variables	coef	exp (coef)	P value
Model I	Periodontal treatment experience (ref = Yes)
	No	0.688	1.991	< 0.001
Model II	Periodontal treatment experience (ref = Yes)
	No	0.602	1.826	< 0.001
	Systematic diseases (ref = No)
	Ischemic heart diseases	0.339	1.404	< 0.001
	Cerebrovascular diseases	0.067	1.069	< 0.001
	Kidney diseases	1.177	3.247	< 0.001
	Diabetes mellitus	0.432	1.541	< 0.001
	Sex (ref = Male)
	Female	− 0.632	0.531	< 0.001
	Age	0.051	1.052	< 0.001
	Health Insurance (ref = Health insurance holders)
	Medical aid	0.139	1.150	< 0.001
	Residential areas (ref = metropolitan areas)
	Small/medium-sized cities	− 0.032	0.968	< 0.001
	Rural areas	− 0.023	0.977	< 0.001

Coef coefficients, ref Reference group.