Table 2.

Intraindividual variability in Hb levels dependent on ESA usage, defined by residual SD of Hb, intraindividual change in Hb in consecutive measurements, Hb amplitude, and Hb category

Hb Variability DefinitionsNo ESA Use (n = 3143)On ESA Throughout (n = 1823)Commenced ESA (n = 1199)P
Hb intercept (g/L; mean ± SD)124.9 ± 15.3112.6 ± 15.4103.1 ± 11.8<0.0001
Hb slope (g/L per mo; mean ± SD)−0.1 ± 2.61.4 ± 4.12.7 ± 4.0<0.0001
Residual SD (g/L; mean ± SD)4.9 ± 4.46.8 ± 4.87.3 ± 4.9<0.0001
Intraindividual change in Hb (g/L; mean ± SD)6.6 ± 5.38.6 ± 5.59.7 ± 5.6<0.0001
SD of intraindividual change in Hb (g/L; mean ± SD)8.0 ± 7.410.0 ± 7.211.1 ± 7.5<0.0001
Hb change (%)
    all consecutive Hb change ≤5 g/L25.17.44.7<0.0001
    consecutive Hb decrease >5 g/L19.931.038.8
    consecutive Hb increase >5 g/L24.111.87.3
    both consecutive Hb decrease and increase >5 g/L30.949.849.2
Hb amplitude (g/L; %)
    0 to 1050.018.212.9<0.0001
    11 to 2033.737.033.3
    >2016.344.853.8
Classification of Hb variability (%)<0.0001
    group I (Hb >130 g/L)22.82.90.3
    group II (Hb >130 and 110 to 130 g/L)24.122.34.6
    group III (Hb 110 to 130 g/L)24.612.85.1
    group IV (Hb 110 to 130 and <110 g/L)18.433.949.6
    group V (Hb <110 g/L)5.411.117.3
    group VI (Hb >130 and 110 to 130 and <110 g/L)4.717.023.1