Table 1.

Clinical characteristics in the development, internal, and external validation data sets

CharacteristicDevelopmentInternal ValidationExternal Validation
Number of participants1644822987
Age (years)44 ± 1443 ± 1450 ± 16c
Female41% (669)44% (360)40% (404)
Black race11% (179)8% (67)b6% (57)c
Weight (kg) ± SD77 ± 1677 ± 1678 ± 16
Height (cm) ± SD171 ± 1071 ± 10171 ± 10
Body mass index (kg/m2) ± SD26.2 ± 4.56.2 ± 4.526.2 ± 4.7
BSA (m2) ± SD1.89 ± 0.221.88 ± 0.221.89 ± 0.23
Serum creatinine (mg/dl)a1.4 (1.0, 2.1)1.4 (1.0, 2.2)1.6 (1.1, 2.3)c
GFR (ml/min per 1.73 m2)a49 (30, 89)49 (29, 91)48 (30, 74)c
GFR categories
    ≥9025% (407)25% (209)14% (141)c
    60 to 8915% (246)14% (118)23% (223)c
    30 to 5935% (574)33% (272)39% (384)c
    <3025% (417)27% (221)24% (239)c
Albumin (g/dl)a4.0 (3.8, 4.2)4.0 (3.7, 4.2)4.2 (3.8, 4.4)c
Phosphorus (mg/dl)a3.6 (3.2, 4.1)3.7 (3.3, 4.3)b3.6 (3.2, 4.1)d
CER (mg/d)a1369 (1080, 1724)1340 (1070, 1700)1314 (1041, 1630)c
  • a Median (interquartile range).

  • b P < 0.05 compared with the development data set.

  • c P < 0.01 compared with the combined development and internal validation data sets.

  • d P < 0.05 compared with the combined development and internal validation data sets.