Table 3.

Cox regression analysis of hypophosphatemia versus mortality risk

ModelHypophosphatemia Category, HR [95% CI]Lowest Serum Phosphate per 1 mg/dl
AbsentMildSevereHR [95% CI]P Value
All-cause mortality (295 events)
 CrudeReference1.01 [0.69 to 1.47]0.97 [0.67 to 1.41]0.93 [0.74 to 1.19]0.59
 Model 1Reference0.96 [0.65 to 1.40]0.89 [0.61 to 1.30]0.85 [0.67 to 1.09]0.20
 Model 2Reference1.01 [0.69 to 1.48]1.02 [0.69 to 1.50]0.93 [0.71 to 1.20]0.69
 Model 3Reference1.14 [0.68 to 1.90]1.21 [0.72 to 2.03]0.92 [0.73 to 1.35]0.96
 Model 4Reference0.93 [0.55 to 1.58]0.98 [0.58 to 1.67]0.90 [0.66 to 1.23]0.53
 Model 5Reference1.02 [0.59 to 1.80]1.19 [0.68 to 2.08]1.08 [0.77 to 1.52]0.66
 Model 6Reference1.02 [0.60 to 1.72]1.18 [0.70 to 1.99]1.15 [0.82 to 1.63]0.42
Cardiovascular mortality (94 events)
 CrudeReference0.73 [0.42 to 1.29]0.58 [0.33 to 1.02]0.45 [0.28 to 0.63]<0.001
 Model 1Reference0.65 [0.37 to 1.16]0.53 [0.30 to 0.94]a0.40 [0.29 to 0.56]<0.001
 Model 2Reference0.65 [0.37 to 1.15]0.53 [0.29 to 0.97]a0.38 [0.27 to 0.55]<0.001
 Model 3Reference0.64 [0.35 to 1.18]0.50 [0.26 to 0.95]a0.39 [0.25 to 0.60]<0.001
 Model 4Reference0.62 [0.32 to 1.18]0.44 [0.22 to 0.88]a0.38 [0.24 to 0.59]<0.001
 Model 5Reference0.44 [0.21 to 0.91]a0.36 [0.17 to 0.77]b0.39 [0.24 to 0.64]<0.001
 Model 6Reference0.45 [0.21 to 0.95]a0.38 [0.17 to 0.84]a0.36 [0.21 to 0.61]<0.001
Noncardiovascular mortality (176 events)
 CrudeReference0.85 [0.57 to 1.27]0.83 [0.56 to 1.23]0.91 [0.69 to 1.19]0.49
 Model 1Reference0.84 [0.56 to 1.25]0.80 [0.54 to 1.19]0.85 [0.65 to 1.12]0.25
 Model 2Reference0.93 [0.61 to 1.40]1.00 [0.66 to 1.52]1.01 [0.74 to 1.35]0.99
 Model 3Reference1.14 [0.68 to 1.90]1.21 [0.72 to 2.03]1.16 [0.82 to 1.64]0.40
 Model 4Reference0.93 [0.55 to 1.58]0.98 [0.58 to 1.67]1.04 [0.73 to 1.52]0.80
 Model 5Reference1.03 [0.59 to 1.80]1.19 [0.68 to 2.08]1.22 [0.85 to 1.79]0.28
 Model 6Reference1.04 [0.59 to 1.83]1.27 [0.71 to 2.25]1.32 [0.89 to 1.96]0.15
  • Model 1: adjusted for recipient age and sex. Model 2: model 1 plus eGFR at the time of the lowest phosphate. Model 3: model 2 plus donor age and sex, donor type, cold ischemia time, delayed graft function, and proteinuria (at the time of the lowest serum phosphate). Model 4: model 3 plus total number of HLA mismatches, acute rejection, induction and maintenance immunosuppressive use, and panel of reactive antibodies. Model 5: model 4 plus cardiovascular risk factors (dialysis vintage, smoking status, pretransplant diabetes mellitus, and cardiovascular history). Model 6: model 5 plus phosphate supplementation, vitamin D supplementation, vitamin D supplementation pretransplantation, and corrected calcium concentrations (before transplantation and at the time of the lowest serum phosphate). HR, hazard ratio; 95% CI, 95% confidence interval.

  • a P<0.05.

  • b P<0.01.