CAN ANEMIA BE A CONFOUNDER IN NT-PROBNP INTERPRETATION?

Heart failure is a major clinical issue of concern worldwide. Many biomarkers are used to aid the diagnosis of heart failure patients. One of the increasingly used biomarkers is the biologically inactive NT-proBNP. Several confounding factors affect plasma NT-proBNP levels, and hence, the validity of its interpretation. Heart failure and anemia are well correlated, as evidenced by variety of studies. In, anemia can yield some degree of cardiac stress that leads to the expression of NT-proBNP levels above the cut-off values. This study aimed to test whether anemia can be associated with an elevated peptide level in patients without heart failure. A cross-sectional study in which a total of 108 randomly selected patients, irrespective of their hemoglobin levels, were recruited. Males comprised 39.8% of the total, and the patients were divided based on their hemoglobin levels into anemic (55 patients) and non-anemic (53 patients) groups. Plasma NT-proBNP levels were assessed using ELISA, and the results were interpolated and analyzed against hemoglobin levels. The NT-proBNP level was significantly higher in patients with anemia (p < .0001) where it was 268.7 ± 38.9 vs. 93.55 ± 17.4 ng/dl for both the anemic and non-anemic groups, respectively. Hemoglobin level showed a negative correlation with plasma peptide level ([F (1, 107) = 28.63, p < .0001)], with an r2 of 0.358. Anemia is inversely correlated with the plasma NT-proBNP level. In fact, anemia can raise the peptide level beyond its recommended cutoff levels making the interpretation of the raised NT-proBNP more challenging.