Table 2. Univariate and multivariate analysis for potential confounding factors for death from heart disease for all patients surviving 6 months.

Variables	Univariate				Multivariate
	HR	95% CI	P value		HR	95% CI	P value
RT	1.42	1.29-1.57	<0.0001		1.46	1.32-1.61	<0.0001
Age	1.7	1.63-1.79	<0.0001		1.74	1.67-1.82	<0.0001
Gender	0.99	0.89-1.09	0.79
Race	0.9	0.85-0.96	0.002		0.86	0.81-0.92	<0.0001
Extent of disease	1.06	1.05-1.08	<0.0001		1.04	1.02-1.05	<0.0001
Time period of diagnosis	0.72	0.68-0.76	<0.0001		0.72	0.67-0.76	<0.0001
Known comorbid conditions	1.63	1.24-2.14	0.0012		1.34	1.02-1.76	0.04

HR, hazard ratio; CI, confidence interval; RT, radiation therapy.