Prevalence and clinical associations of iron deficiency in patients with decompensated heart failure, depending on the diagnostic criteria used for iron deficiency

Aim. To compare the frequency of iron deficiency (ID) in patients with decompensated heart failure (HF), defined by international guideline criterion – ferritin <100 ng/ml or ferritin from 100 to 299 ng/ml with TSAT<20% (criterion A) and by bone marrow biopsy criterion – TSAT<19.8% and serum iron <13 µmol/l (criterion B); to evaluate the effect of ID, diagnosed on the basis of different ID criteria, on NT pro-BNP, sST2, CRP levels and New York Heart Association (NYHA) functional classes (FC) distribution between groups with ID and without ID.

Materials and methods. The study included 223 patients (median age 73 [65; 82] years, 58% males) who were hospitalized to V.V. Vinogradov Moscow City Clinical Hospital No. 64 with decompensated HF. All patients underwent a standard physiological examination, laboratory and instrumental studies, including determination of NT-proBNP, sST2, CRP, and ferrokinetic parameters (serum iron, transferrin, ferritin). TSAT was calculated as: serum iron / transferrin × 3.98. NYHA FC was determined according to Heart Failure Severity Rating Scale score. All patients underwent echocardiography to assess the ejection fraction of the left ventricle.

Results. According to criterion A ID was detected in 89% (n=199) of patients. There were no significant differences between levels of CRP, NT-proBNP and sST2. According to criterion B ID was detected in 70% (n=156) of patients. In the ID group, higher levels of CRP (15.1 mg/l vs 6.2 mg/l, p<0.001), NT-proBNP (5422 pg/ml vs 2380 pg/ml, p<0.001) and sST2 (59.6 ng/ml vs 42 ng/ml, p=0.02) were detected. Intravenous FCM admission according to current international guidelines (diagnosis of ID according to criterion A) is recommended to 57% of patients included in this study. Both methods formed groups with ID, in which patients had higher NYHA FC compared to groups without ID. According to current clinical guidelines, iron deficiency should be assessed according to method 1. More than half of patients (57, n=127) have indications for intravenous FCM to reduce risk of HF hospitalizations.

Conclusion. The frequency of ID in patients with decompensated heart failure varies from 70 to 89% depending on the criterion used to diagnose ID, but in any case, remains high. Intravenous FCM should be prescribed in 57% (n=127) of patients. Criterion B, validated against the gold standard of diagnostics, unlike criterion A, makes it possible to form groups of patients with ID and without ID, significantly differing in CRP, NT-proBNP, and sST2 levels.