Iron deficiency anemia detection from hematology parameters in adult congenital heart disease patients

Iron deficiency anemia is the most common single cause of anemia worldwide. The purpose of our study was to estimate the prevalence of anemia in adult congenital heart disease (ACHD) patients, compare different hematology parameters between hypoxemic and nonhypoxemic ACHD patients, and determine which parameters detect iron deficiency anemia in hypoxemic ACHD patients.

ACHD patients were studied and blood samples collected for determination of hemoglobin, derived red cell indices, serum iron, apoferritin, total iron-binding capacity, transferrin saturation index, C-reactive protein (CRP), and N-terminal proB-type natriuretic peptide (NT-proBNP) levels.

Two hundred seventy-eight ACHD patients, mean age 31.6 ± 14.3 years old, were studied. One hundred sixty-seven (60%) patients were male. Two hundred forty-five patients were nonhypoxemic and 33 patients were hypoxemic. Hypoxemic ACHD patients had significant higher hemoglobin concentration (g/dL) (17.5 ± 3.5 vs. 14.6 ± 1.7, P <.001), red cell distribution width (RDW) (%) (17.0 ± 3.3 vs. 14.1 ± 7.6, P <.034), apoferritin (ng/mL) (19.8 [4.1-147.2] vs. 38.0 [6.7-191.2], P =.019), CRP (mg/dL) (0.50 [0.0-3.8] vs. 0.12 [0.0-1.4], P <.001), and NT-proBNP (pg/mL) (409.3 [33.3-9830.8] vs. 5.2 [0.0-1068.4], P <.001) levels than nonhypoxemic ACHD patients. Serum iron, total iron-binding capacity, and transferrin saturation index were not statistically significant between hypoxemic and nonhypoxemic ACHD patients. In the hypoxemic group, 15 (45%) patients had apoferritin levels <20 ng/mL and eight (24%) patients developed microcytosis and hypochromia. A RDW above the normal range (>14.5%) in hypoxemic ACHD patients allowed the detection of an apoferritin level <20 ng/mL with a sensitivity of 93%.

RDW seems to be a useful and economic tool to detect low serum apoferritin levels in hypoxemic ACHD patients.