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
H.R.aEstimate [LL, UL] P-value P-value H.R. Rangeb(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.

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

Open Data