Iron deficiency in patients with heart failure with preserved ejection fraction and its association with reduced exercise capacity, muscle strength and quality of life

Abstract

Background: The prevalence of iron deficiency (ID) in outpatients with heart failure with preserved ejection fraction (HFpEF) and its relation to exercise capacity and quality of life (QoL) is unknown.

Methods: 190 symptomatic outpatients with HFpEF (LVEF 58 ± 7%; age 71 ± 9 years; NYHA 2.4 ± 0.5; BMI 31 ± 6 kg/m²) were enrolled as part of SICA-HF in Germany, England and Slovenia. ID was defined as ferritin < 100 or 100-299 µg/L with transferrin saturation (TSAT) < 20%. Anemia was defined as Hb < 13 g/dL in men, < 12 g/dL in women. Low ferritin-ID was defined as ferritin < 100 µg/L. Patients were divided into 3 groups according to E/e' at echocardiography: E/e' ≤ 8; E/e' 9-14; E/e' ≥ 15. All patients underwent echocardiography, cardiopulmonary exercise test (CPX), 6-min walk test (6-MWT), and QoL assessment using the EQ5D questionnaire.

Results: Overall, 111 patients (58.4%) showed ID with 89 having low ferritin-ID (46.84%). 78 (41.1%) patients had isolated ID without anemia and 54 patients showed anemia (28.4%). ID was more prevalent in patients with more severe diastolic dysfunction: E/e' ≤ 8: 44.8% vs. E/e': 9-14: 53.2% vs. E/e' ≥ 15: 86.5% (p = 0.0004). Patients with ID performed worse during the 6MWT (420 ± 137 vs. 344 ± 124 m; p = 0.008) and had worse exercise time in CPX (645 ± 168 vs. 538 ± 178 s, p = 0.03). Patients with low ferritin-ID had lower QoL compared to those without ID (p = 0.03).

Conclusion: ID is a frequent co-morbidity in HFpEF and is associated with reduced exercise capacity and QoL. Its prevalence increases with increasing severity of diastolic dysfunction.

Keywords: Exercise capacity; Heart failure with preserved ejection fraction; Iron deficiency; Quality of life.