Low testing rates for iron deficiency in patients with HF
Phenotyping heart failure patients for iron deficiency and use of intravenous iron therapy: data from the Swedish Heart Failure Registry
Introduction and methods
Iron deficiency (ID) is associated with high risk of hospitalizations and mortality in patients with HF . This study investigated the likelihood and predictors of being tested for ID, the prevalence and outcomes of ID, and the use of ferric carboxymaltose (FCM) in the Swedish Heart Failure Registry (SwedeHF) .
The study included all patients enrolled in SwedeHF between 1 January 2017 and 31 December 2018 (n=21496). ID was defined as ferritin <100 µg/L, or ferritin 100-299 µg/L and transferrin saturation <20%. Anemia was defined as hemoglobin <12.0 g/dL in women and <13 g/dL in men. Patients without data on ferritin or transferrin saturation were considered as not being tested for ID. Baseline characteristics were compared across patients with vs. without ID and with vs. without anemia. Additionally, Baseline characteristics were compared across patients tested vs. not tested for ID and receiving vs. not receiving FCM. Investigated outcomes were: the composite of time to first HF hospitalization or all-cause death, time to first HF hospitalization, time to all-cause death, time to first all-cause hospitalization, and time to first HF outpatient visit. Median follow-up was 19.4 (IQR 0.1-35.9) months.
- Of 21496 patients registered in SwedeHF, 5708 (27%) were tested for ID.
- Independent predictors associated with higher likelihood of ID testing were: enrolment as an outpatient, more severe or symptomatic HF (defined as higher NYHA class, use of diuretics and MRAs), having HFrEF vs. HFmrEF vs. HFpEF, use of betablockers, anemia, male sex, longer HF duration, referral to follow-up in a HF clinic or in primary care, and registration in SwedeHF in 2018 vs. 2017.
- Of tested patients, 49% had ID. When stratified to the presence or absence of ID and anemia, 36% had ID−/anemia−, 15% had ID−/anemia+, 29% had ID+/anemia−, and 20% had ID+/anemia+.
- ID+/anemia+ was associated with the highest risk of all outcomes, except for first HF visit (all-cause death/first HF hospitalization: adjusted (a) HR 1.48, 95%CI 1.25-1.74, P <0.001; all-cause death: aHR 1.55, 95%CI 1.23-1.95, P <0.001; first HF hospitalization: aHR 1.38, 95%CI 1.14-1.67, P=0.001; first all-cause hospitalization: aHR 1.39, 95%CI 1.23-1.58, P<0.001, compared to ID-/anemia-).
- ID−/anemia+ was associated with higher risk of all-cause death/first HF hospitalization (aHR 1.23, 95%CI 1.03-1.48, P =0.024) and all-cause death (aHR 1.41, 95%CI 1.10-1.82, P =0.008), compared to ID-/anemia-.
- There were no significant differences in risk of outcomes between ID+/anemia- and ID-/anemia-.
- 19% of patients with ID received FCM. Independent predictors of FCM use were more severe HF (defined as higher NYHA class and MRA use), HFrEF vs. HFmrEF vs. HFpEF, lower hemoglobin levels, diabetes and follow-up to specialty care.
In SwedeHF, approximately 1 in 4 patients with HF were tested for ID. ID was present in half of the tested population. 1 in 5 patients with ID received FCM.