Association of Iron Deficiency With the Severity of Heart Failure With Preserved Ejection Fraction: A Hospital-Based Comparative Observational Study From Bangladesh

Background Iron deficiency is a prevalent and clinically significant comorbidity in heart failure with preserved ejection fraction (HFpEF), yet local data from Bangladesh remain scarce. This study aimed to examine the association between iron deficiency and heart failure severity among patients with HFpEF attending a tertiary cardiac center in Dhaka. Methods This hospital-based comparative observational study enrolled 120 adult patients with HFpEF at Dhaka Medical College Hospital between July 2023 and June 2024. Patients were divided into two groups based on iron status: iron-deficient (Group I, n=60) and iron-replete (Group II, n=60). Iron deficiency was defined according to contemporary heart failure guidelines. Heart failure severity was assessed using the New York Heart Association (NYHA) functional classification, serum N-terminal pro-B-type natriuretic peptide (NT-proBNP) level, and echocardiographic diastolic dysfunction grading per the 2016 ASE/EACVI recommendations. Statistical analysis was performed using SPSS version 26.0 (IBM Corp., Armonk, USA), employing the independent-samples t-test for continuous variables and the chi-square or Fisher's exact test for categorical variables, as appropriate. Results Iron-deficient patients were significantly older (66.1±8.66 vs. 57.87±8.16 years; p < 0.001) and had substantially higher anaemia prevalence (63.3% vs. 18.3%; p<0.001). Iron deficiency was significantly associated with higher NYHA functional class (p=0.003), markedly elevated NT-proBNP levels (3256.75 ± 1124.30 vs. 2099.07 ± 987.50 pg/mL; p < 0.001), and more advanced diastolic dysfunction (p=0.028), with Grade 2 diastolic dysfunction predominating and Grade 3 diastolic dysfunction being more frequent in the iron-deficient group. Conclusions Iron deficiency was significantly associated with greater HFpEF severity across functional, biochemical, and echocardiographic domains, though baseline differences in age and anaemia may have contributed to this unadjusted association. These findings support further evaluation of routine iron status assessment in HFpEF management in Bangladesh, warranting confirmation through prospective, multicenter studies with multivariable adjustment.