Table 3. Bivariable and multivariable piecewise Cox proportional hazards model for mortality predictors during the first year of dialysis or thereafter

VariableNumber at Risk or Median (range)Bivariate AnalysisMultivariable Analysis
0 to 12 mo HRa (95% CI)>12 mo HRa (95% CI)0 to 12 mo HRa (95% CI)>12 mo HRa (95% CI)
a HR, hazards ratio, related to 1-yr increment for age or year of referral, to 1-kg/m2 increment for BMI (body mass index), or to 1-point increment in Karnofsky score (full scale); CI, confidence interval.
b P < 0.05.
c P < 0.01.
d P < 0.001.
e Refers to the number of comorbid conditions (listed in Table 1).
Gender
    male5611
    female452.56 (1.13 to 5.79)b0.43 (0.20 to 0.91)b
Age at inclusion (yr)83 (80 to 94)1.13 (1.01 to 1.27)b1.00 (0.88 to 1.15)
Year of referral (1989 to 2000)19960.98 (0.89 to 1.08)0.95 (0.87 to 1.03)
Karnofsky score (full scale)70 (10 to 100)0.97 (0.95 to 0.99)c0.99 (0.97 to 1.01)
Karnofsky functional class
    100 to 80 (normal activity)321111
    70 to 50 (require assistance)471.28 (0.47 to 3.53)1.53 (0.66 to 3.54)11
    40 to 10 (dependent patients)222.96 (1.05 to 8.33)b1.83 (0.68 to 4.92)2.34 (1.00 to 5.50)b1.00 (0.42 to 2.36)
BMI (per kg/m2)21.5 (13 to 33.6)0.84 (0.74 to 0.96)c1.04 (0.95 to 1.14)0.83 (0.73 to 0.95)c1.00 (0.91 to 1.10)
Need for dialysis catheter412.87 (1.29 to 6.39)c0.59 (0.27 to 1.28)
Unplanned first dialysis351.96 (0.89 to 4.29)0.74 (0.35 to 1.56)
Late referral282.45 (1.11 to 5.40)b0.60 (0.25 to 1.46)2.28 (1.02 to 5.11)b0.68 (0.26 to 1.77)
Ischemic heart disease430.96 (0.43 to 2.13)1.05 (0.54 to 2.04)
Congestive heart failure410.75 (0.33 to 1.70)1.59 (0.80 to 3.14)
Peripheral vascular disease231.15 (0.46 to 2.87)5.91 (2.73 to 12.83)d1.03 (0.40 to 2.67)5.67 (2.45 to 13.11)d
Sum of comorbid conditionse
    02411
    1 to 2530.71 (0.27 to 1.82)1.68 (0.70 to 4.02)
    ≥3241.10 (0.38 to 3.11)3.73 (1.28 to 10.91)b