Iron deficiency in primary care patients with heart failure: a cross-sectional study of the heart failure in Southern Sweden (HISS) cohort.

BACKGROUND

Iron deficiency is a common and clinically relevant comorbidity in heart failure, associated with reduced functional capacity, higher symptom burden, and increased hospitalisation risk. Most evidence on iron deficiency in heart failure originates from hospital-based cohorts, whereas the epidemiology and clinical implications in primary care populations remain poorly described. This study aimed to determine the prevalence of iron deficiency among primary care patients with heart failure in southern Sweden and to examine its association with symptom severity.

METHODS

This cross-sectional analysis used baseline data from the Heart Failure in Southern Sweden study, a prospective intervention project conducted at 20 primary health care centres. Adult patients with heart failure across all left ventricular ejection fraction categories were included. Iron deficiency was defined as transferrin saturation < 20%.

RESULTS

In total, 466 primary care patients with heart failure were included, of whom 124 (26.7%) had iron deficiency. Symptom severity was higher in patients with iron deficiency: 35.5% were classified as New York Heart Association (NYHA) class III-IV, compared with 18.7% among patients without iron deficiency. Similar findings were observed in the subgroup with left ventricular ejection fraction below 50%, where 25.2% had iron deficiency and 42.6% were classified as NYHA III-IV compared with 18.4% among patients without iron deficiency. In multivariable analysis adjusting for clinically relevant covariates, iron deficiency remained associated with NYHA class III-IV (OR 1.97, 95% CI 1.18-3.31, p = 0.010).

CONCLUSIONS

Iron deficiency is common among patients with heart failure managed in primary care and remained associated with higher symptom burden after adjustment for prespecified covariates. These findings highlight the potential clinical relevance of assessment of iron status in primary care.

TRIAL REGISTRATION: ClinicalTrials.gov, NCT04129658. Registered on 15 October 2019.