The prevalence of iron deficiency and anemia and their impact on survival in patients at a cardio-oncology clinic

BACKGROUND: Iron deficiency (ID) and anemia are common in both heart failure (HF) and cancer patients and are associated with poor quality of life and survival. The aims of this study were (1) to evaluate the prevalence, types, and confounding factors of ID and anemia in patients referred to cardio-oncology clinic, and (2) identify the association between iron metabolism parameters and survival of cardio-oncology patients. METHODS: We assessed iron, ferritin, hemoglobin concentrations, transferrin saturation (TSAT), cancer type, brain natriuretic peptide (BNP), left ventricular ejection fraction (LVEF), kidney function, cardiovascular risk factors and survival in 599 patients who were referred to cardio-oncology clinic from 2011 to 2017. ID was defined by a TSAT < 20%, absolute iron deficiency (AID) with a serum ferritin level < 100 μg/L while serum ferritin level of ≥ 100 μg/L was considered as functional iron deficiency (FID) and TSAT ≥ 20% was considered as no ID. RESULTS: The prevalence of ID, AID, and FID was 46, 31, and 15% of study patients, respectively. Anemia was present in approximately half (54%) of the patients with any ID. Multivariate Cox analyses showed that male gender (HR 1.704 [1.207–2.404] p = 0.002); previous cancer history (HR 1.879 [1.079–3.272] p = 0.026); elevated BNP (HR 2.126 [1.258–3.590] p = 0.005); TSAT< 20% (HR 1.721 [1.214–2.439] p = 0.002); ferritin ≥ 100 μg/L (HR 2.008 [1.088–3.706] p = 0.026); serum iron concentration < 12 μmol/L (HR 2.292 [1.614–3.255] p < 0.001); FID (HR 2.538 [1.1618–3.981] p < 0.001) and anemia (HR 2.462 [1.734–3.495] p < 0.001) were significantly associated with increased risk of all-cause death. CONCLUSIONS: About half of cardio-oncology patients had anemia and iron deficiency, with the absolute type being twice as prevalent as the functional one. Patients with breast, gastrointestinal, and genitourinary cancer were affected more often. Both anemia and iron deficiency independently predicted all-cause mortality. Future studies are required to confirm ID as a risk factor and evaluate the clinical benefits of iron replacement therapy.