Table 3.

Independent associations with erythropoietin (natural log) in multivariate analysis

	Beta (95% CI)	Standardized beta	P
All patients, *N = 179†
Hemoglobin, g/L	−3.1 (−3.6-−0.26)	−0.69	<.001
Hemoglobin F, %	0.02 (0.01-0.03)	0.27	<.001
Patients on hydroxyurea, n = 72‡
Hemoglobin, g/L	−2.7 (−3.8-−1.7)	−0.58	<.001
Hemoglobin F, %	0. 03 (0.01-0.05)	0.32	.005
Patients not on hydroxyurea, n = 107§
Hemoglobin, g/L	−3.3 (−3.9-−2.8)	−0.80	<.001
Hemoglobin F, %	0.01 (0-0.02)	0.12	.09

^*Includes patients for whom hemoglobin F and erythropoietin results were available. Variables entered into models were hemoglobin, hemolytic component, hemoglobin oxygen saturation, and hemoglobin F (%).

^†R-square = 0.51. If hemoglobin F category of 8% or higher versus lower than 8% is used in the model, P value for hemoglobin F = .001.

^‡R-square = 0.34. If hemoglobin F category of 8% or higher versus lower than 8% is used in the model, P value for hemoglobin F = .015.

^§R-square = 0.61. If hemoglobin F category of 8% or higher versus lower than 8% is used in the model, P value for hemoglobin F = .3.