Table 3.

Multivariate Cox proportional hazard model of first heart failure event during follow-up in patients on hemodialysis (indoxyl sulfate entered as a continuous or dichotomous variable)

ModelHazard Ratio95% Confidence IntervalP value
Indoxyl sulfate (continuous variable)
 Unadjusted1.021.01 to 1.030.001
 Model 11.021.01 to 1.030.001
 Model 21.021.01 to 1.04<0.001
 Model 31.021.01 to 1.030.003
 Model 41.031.01 to 1.040.002
 Model 51.031.01 to 1.040.001
 Model 61.021.01 to 1.030.001
 Model 71.021.01 to 1.040.001
 Model 81.021.01 to 1.03<0.01
 Model 91.021.01 to 1.03<0.001
 Model 101.041.02 to 1.06<0.001
Indoxyl sulfate (dichotomous variable)
 Unadjusted3.491.97 to 6.20<0.001
 Model 13.662.05 to 6.56<0.001
 Model 23.381.90 to 6.02<0.001
 Model 34.142.07 to 8.26<0.001
 Model 44.362.13 to 8.900.001
 Model 53.952.09 to 7.47<0.001
 Model 62.491.30 to 4.76<0.01
 Model 73.421.82 to 6.42<0.001
 Model 83.782.00 to 7.15<0.001
 Model 93.792.13 to 6.74<0.001
 Model 105.312.43 to 11.58<0.001
  • Model 1: adjusted for age, sex, and body mass index. Model 2: adjusted for history of primary hypertension, coronary heart disease, and diabetes. Model 3: adjusted for urinary volume, ultrafiltration volume, average interdialytic weight gain, residual renal function, and single-pool Kt/V. Model 4: adjusted for albumin, prealbumin, BUN, serum creatinine, uric acid, and normalized protein nitrogen appearance rate. Model 5: adjusted for LDL-cholesterol, HDL-cholesterol, apoprotein-A, apoprotein-B, and homocysteine. Model 6: adjusted for P, Ca×P, intact parathyroid hormone, and 25-hydroxy vitamin D. Model 7: adjusted for high-sensitivity C-reactive protein and β2-microglobulin. Model 8: adjusted for left ventricular mass index and left ventricular ejection fraction. Model 9: adjusted for history of taking calcium channel blocker, angiotensin conversion enzyme inhibitor, angiotensin receptor blocker, β-blocker, α-blocker, aspirin, and statin. Model 10: adjusted for hierarchically selected covariates of age, systolic BP, history of primary hypertension, history of coronary heart disease, history of diabetes, prealbumin, 25-hydroxy vitamin D, LDL-cholesterol, apoprotein-B, left ventricular mass index, and left ventricular ejection fraction. In Model 10, the backward conditional method was used.