Iron deficiency in a multi-ethnic Asian population with and without heart failure: prevalence, clinical correlates, functional significance and prognosis

Abstract

Aims: Current heart failure (HF) guidelines highlight the importance of iron deficiency (ID) in HF. Whether HF itself or age-related comorbidities contribute to ID is uncertain, and previous data were limited to Western populations. We aimed to study the prevalence, clinical correlates, functional significance and prognosis of ID in HF patients, compared with community-based controls in a multi-ethnic Southeast Asian population.

Methods and results: Iron status was assessed in 751 HF patients (age 62.0 ± 12.2 years, 75.5% men, 64.7% Chinese, 23.9% Malay, 10.2% Indian) and 601 controls (age 56.9 ± 10.4 years, 49.8% men, 70.9% Chinese, 21.5% Malay, 7.2% Indian). ID, defined as ferritin <100 µg/L or ferritin 100-300 µg/L and transferrin saturation (Tsat) <20%, was present in 39.3% of controls and 61.4% of HF [odds ratio (OR) 3.5, 95% confidence interval (CI) 2.5-4.9, adjusting for clinical covariates]. Independent correlates of ID in HF were Indian ethnicity (OR 2.4 vs. Chinese, 95% CI 1.2-5.0), female gender (OR 2.8, 95% CI 1.7-4.8), larger body mass index (OR 1.05/unit increase, 95% CI 1.01-1.1) and decreased left ventricular ejection fraction (OR 1.03/unit decrease, 95% CI 1.01-1.04). In a subset of 48 HF patients undergoing cardiopulmonary exercise testing, Tsat correlated with peak oxygen consumption (ρ = 0.53, P < 0.01), independent of baseline characteristics. The HF patients with Tsat <20% as well as anaemia showed the poorest event-free survival after adjusting for clinical covariates.

Conclusions: ID was highly prevalent and independently related to functional capacity and outcomes in our cohort. These findings suggest a pathophysiological role of ID in HF and support its importance as a therapeutic target in Southeast Asian patients with HF.

Keywords: Exercise capacity; Heart failure; Iron deficiency.