Natural history and prognostic significance of anaemia and iron deficiency in ambulatory patients with heart failure
Abstract Background Anaemia and iron deficiency (ID) are both common and associated with adverse outcomes in patients with heart failure (HF). However, the incidence of and recovery from anaemia and ID and their impact on prognosis are not well described. Methods Between 2001 and 2018, patients with suspected HF referred to a clinic serving a local population of ∼500,000 were invited to be enrolled in a long-term registry. HF was defined as relevant symptoms or signs with either at least moderate systolic dysfunction on echocardiography or raised plasma concentration of amino-terminal pro-B type natriuretic peptide (NT-proBNP ≥125pg/ml). ID was defined as a transferrin saturation (TSAT) of <20%, anaemia was defined as a haemoglobin (Hb) of <13.0 g/dL in men and <12.0 g/dL in women. At 1-year follow-up, 872 patients had repeat assessments for ID. Patients were grouped into four phenotypes according to the presence or absence of anaemia and/or ID. Those who developed or recovered from ID and anaemia were assessed separately. Survival analysis was conducted at 5 years after the one-year visit. Results The prevalence of ID and anaemia at baseline was 40% and 29% respectively. At baseline and at one-year, 53% of patients had either ID, anaemia or both. Compared to other groups, those with both anaemia and ID were older, had worse renal function and higher median NT-proBNP. In patients with TSAT >20% without anaemia at baseline, 23% had ID at 1 year, 14% were anaemic and 6% developed both. At one year, 11% of patients with anaemia and ID at baseline had normal values for both compared to 16% of those with anaemia but not ID. In patients with ID without anaemia at baseline, 51% remained iron deficient at one year, irrespective of initial Hb. At 5-years, survival was markedly worse for those with anaemia at baseline compared to those without anaemia, irrespective of iron status. Compared to those who had normal TSATs and Hb, those with both anaemia and ID had the worst survival (HR=2.35; 1.77–3.11; p<0.001), followed by those with anaemia without ID (HR=1.93; 1.40–2.67; p<0.001) and those with isolated ID (HR=1.34; 1.01–1.78; p=0.046). Compared to patients who never had anaemia or ID, patients who developed (HR 2.01; 1.41–2.88; p<0.001) or recovered from (HR 2.21; 1.45–3.39; p<0.001) anaemia or ID (HR 1.61; 1.14–2.28; 0.007 and HR 1.63; 1.16–2.28; 0.005 respectively) had a worse prognosis. Conclusions About 30% of patients with HF who have neither anaemia nor ID will develop such problems within a year and this associated with a worse prognosis. Recovery from ID and anaemia is also common, but this is not associated with a better prognosis. Factors leading to the development of anaemia and ID may be driving prognosis rather than anaemia and ID themselves Funding Acknowledgement Type of funding source: None