title: Sensitivity and specificity of transferrin saturation and serum ferritin as markers of iron status after intravenous iron dextran in hemodialysis patients.
abstract: This study was designed to investigate the effect of intravenous (i.v.) iron dextran (i.d.) on hematocrit (Hct), transferrin saturation (TS), and serum ferritin (SF) in hemodialysis patients treated with a constant dose of erythropoietin (EPO). The sensitivity, specificity, and predictive values of SF and TS for monitoring i.d. therapy were also assessed. All hemodialysis patients with baseline SF < 100 ng/mL or TS < 20%, with EPO dose unchanged 6 weeks before and 4 weeks after dosing with i.d. were included. I.d. (500 mg-1 g) was given as an infusion over 1 h. Patients receiving packed RBC or with active bleeding were excluded. Hct, TS, and SF were measured 2 weeks before and 4 weeks after i.d. Linear correlation coefficients between dose of i.d., changes in Hct, TS, and SF were calculated. The sensitivity, specificity, and predictive values of TS and SF were compared. A positive Hct response was defined as a > 5% increase from baseline 4 weeks after administration of i.d. Thirty-three patients (17 females) received a total of 51 doses of i.d. Mean +/- SD i.d. dose was 770 +/- 278 mg. Hct increased by a mean +/- SD of 4.8% +/- 9.9% (33.4% +/- 3.0% to 34.9% +/- 4.1% [p = 0.028]); SF rose by a median of 208.65% (mean +/- SD of 126.8 +/- 132.1 ng/mL to 325.3 +/- 222.0 ng/mL [p < 0.0001]; TS increased by a median of 53.8% (19.4% +/- 9.4% to 29.3% +/- 11.3% [p < 0.0001]) from baseline values. The correlations between dose of ID and percent changes in SF, TS, and Hct were poor (r2 < 0.02). The sensitivities and specificities were 74% and 36% (TS < 20% alone); 60% and 30% (SF < 100 ng/mL alone); and 33% and 67% (TS < 20% and SF < 100 ng/mL), respectively. The predictive values for positive responses were 48% for TS and 45% for SF when used alone, and 47% when both indices were used together. The predictive value increased to 65% when either SF < 100 ng/mL or TS < 20% were used. At a constant EPO dose, there was a statistically significant increase in Hct 4 weeks after i.d. administration in patients who were diagnosed with iron deficiency by using TS < 20% or SF < 100 ng/mL. The dose of i.d. administered was poorly correlated to changes in Hct, TS, and SF. Both TS and SF are non-specific and insensitive indicators for accurate diagnosis of iron deficiency in hemodialysis patients in EPO.
authors.affiliation: Albany College of Pharmacy, NY 12208, USA.
authors.forename: C L
authors.initials: CL
authors.lastname: Low
authors.forename: G R
authors.initials: GR
authors.lastname: Bailie
authors.forename: G
authors.initials: G
authors.lastname: Eisele
mesh_terms: D000747:Anemia, Hypochromic / Q000175:diagnosis; D015415:Biomarkers / Q000097:blood*; D004921:Erythropoietin / Q000008:administration & dosage; D005260:Female; D005293:Ferritins / Q000097:blood*; D006400:Hematocrit; D006801:Humans; D007275:Injections, Intravenous; D000090463:Iron Deficiencies; D007505:Iron-Dextran Complex / Q000008:administration & dosage*; D008297:Male; D011446:Prospective Studies; D006435:Renal Dialysis / Q000009:adverse effects*; D012680:Sensitivity and Specificity; D014168:Transferrin / Q000032:analysis*
chemical_list: D015415:Biomarkers; D014168:Transferrin; D004921:Erythropoietin; D007505:Iron-Dextran Complex; D005293:Ferritins