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Table 2
Baseline Risk Factors and Associated Mortality Using Unadjusted Cox Proportional Hazard (Cox-PH) and Gray’s Survival Models
Variables	Cox-PH Model		PH test	Grays Model
Variables	H.R.^aEstimate [LL, UL]	P-value	P-value	H.R. Range^b(min – max)	P-value
Diabetes	1.64 [1.43, 1.87]	<0.01	0.05	1.46-2.21	<0.01
Age^£	1.46 [1.38, 1.55]	<0.01	0.98	1.44-1.50	<0.01
Female sex	1.01 [0.88, 1.16]	0.88	0.13	0.91-1.19	0.52
Black race	0.73 [0.64, 0.84]	<0.01	0.09	0.68-0.93	<0.01
BMI	0.98 [0.97, 0.99]	<0.01	0.28	0.96-0.99	<0.01
Yrs of Dialysis	0.99 [0.97, 1.00]	0.18	0.05	0.99-1.01	0.08
Residual urine output	0.97 [0.77, 1.22]	0.80	0.05	0.73-1.22	0.23
≥200 ml/day urine
High Kt/V	0.95 [0.83, 1.08]	0.41	0.72	0.91-0.96	0.88
High Flux	0.95 [0.83, 1.08]	0.41	0.15	0.87-1.11	0.33
Access(Cather vs. All other)	1.91 [1.47, 2.47]	<0.01	0.79	1.75-2.02	<0.01
Comorbidity ICED Score	1.57 [1.44, 1.70]	<0.01	0.79	1.51-1.67	<0.01
Blood Pressure
Systolic*	0.97 [0.91, 1.04]	0.37	<0.01	0.99-1.00	0.01
Diastolic*	0.80 [0.75, 0.86]	<0.01	0.38	0.80-0.87	<0.01
Smoking(Smoked vs. Never)	1.08 [0.99, 1.18]	0.09	0.03	0.95-1.18	0.04
Calcium (mg/dL)	0.93 [0.86, 0.99]	0.03	0.08	0.85-1.01	<0.01
Phosphorus (mg/dL)*	0.98 [0.91, 1.05]	0.55	0.49	0.95-1.01	0.87
Total Cholesterol (mg/dL)*	0.99 [0.92, 1.06]	0.78	0.95	0.97-1.02	0.95
Albumin (mg/dL)	0.57 [0.52, 0.63]	<0.01	<0.01	0.44-0.66	<0.01

Abbreviations: BMI, body mass index; ICED, Index of Coexistent Disease; PH, proportional hazard, H.R., hazard ratio.

^a Hazard Ratio (HR) estimate for each risk factor is presented in the second column which is obtained by fitting the Cox’s time varying single covariate model.

^b A range of HR estimates are obtained for each covariate by fitting Gray’s model. £ Age has been rescaled by dividing 10 for better interpretation of the HR.

*Blood pressure, phosphorus, and total cholesterol have been rescaled by dividing standard deviation for better interpretation of the HR.

Sattar et al. BMC Nephrology 2012 13:130 doi:10.1186/1471-2369-13-130

Table 2