Table 1. Patient characteristics by serum phosphorus categorya

<3 mg/dl (n = 895)3–4 mg/dl (n = 3860)4–5 mg/dl (n = 8723)5–6 mg/dl (n = 10,421)6–7 mg/dl (n = 8367)7–8 mg/dl (n = 4547)8–9 mg/dl (n = 2219)≥9 mg/dl (n = 1506)P Value
a Values are means; medians presented for vintage and ferritin. P values for proportions and means are age-adjusted. BUN, blood urea nitrogen; URR, urea reduction ratio.
Age (years)67.366.464.661.958.655.352.148.7<0.0001
Gender (% female)53%48%50%50%48%48%46%42%<0.0001
Race/ethnicity (%)<0.0001
    white27%37%39%39%35%35%37%44%
    black56%45%42%41%44%44%43%36%
    Hispanic14%15%15%16%17%18%17%16%
    other3%3%4%3%4%4%4%3%
Diabetes (%)46%48%50%49%46%43%40%35%<0.0001
Vintage (years)1.501.461.511.591.821.952.122.07<0.0001
Weight (kg)65.568.870.672.173.974.975.374.8<0.0001
Quetèlet’s (body mass) index (kg/m2)25.125.726.226.727.227.427.827.0<0.0001
Bicarbonate (mEq/L)23.322.621.921.220.619.919.218.1<0.0001
BUN (mg/dl)4751555862656872<0.0001
Creatinine (mg/dl)7.78.08.59.310.311.011.612.2<0.0001
Albumin (g/dl)3.603.743.823.863.903.913.923.93<0.0001
Cholesterol (mg/dl)1631701721731721701671650.05
Hemoglobin (g/dl)10.110.310.510.510.510.410.410.30.002
Ferritin (μg/L)476433431411418408383342<0.0001
URR (%)69.8%69.5%69.4%68.9%68.4%67.7%67.1%65.9%<0.0001