Introduction: This study aimed to evaluate the presence of iron deficiency as a possible factor contributing to poorer outcomes in cardiac resynchronization therapy (CRT). It also sought to explore the relationship between sideropenia (iron deficiency) and the clinical characteristics of the patients.

Patients and Methods: In this cross-sectional study, 121 heart failure patients undergoing CRT were included after providing informed consent (1). Each participant underwent a thorough clinical evaluation, including blood tests and collection of detailed demographic and medical history information.

Results: Sideropenia was observed in 55% of patients, while anemia of any cause was identified in 20.4%. The most frequent condition was prelatent sideropenia, affecting 27% of the cohort, with sideropenic anemia present in 4.5%. When comparing patients with and without sideropenia, no significant differences were noted in demographic factors (such as age, BMI, gender) or general clinical characteristics (e.g., duration of CRT therapy, type of implanted device, baseline heart rhythm, hospitalization history, and blood pressure). However, those with sideropenia exhibited higher rates of arterial hypertension (P=0.001), type II diabetes (P=0.011), and ischemic cardiomyopathy (P=0.011), and were more likely to be on statin therapy (P=0.030). Optimal medical therapy was reached in 69.4% of participants. Additionally, patients with sideropenia were more commonly classified in the higher functional classes of the New York Heart Association (NYHA) (P=0.024, Figure 1) and exhibited elevated NT-proBNP levels (P=0.034). Poorer clinical status correlated with reduced hemoglobin, hematocrit, and serum iron levels, along with increased RDW and the proportion of hypochromic red blood cells. Marginal significance was noted in the reduced transferrin saturation levels in patients belonging to the higher NYHA classes. Moreover, anemia and sideropenia were more prevalent in higher NYHA classes, while patients in lower classes predominantly had neither condition (P=0.011, Figure 2) (1).

Conclusion: The findings highlight a considerable prevalence of sideropenia, which may be a modifiable cause of suboptimal CRT response (2). Its strong association with worsened cardiopulmonary function underscores the need for prompt diagnosis and treatment of sideropenia to improve CRT outcomes in heart failure patients (3, 4).