P6196Iron and infection in patients admitted for heart failure in an internal medicine ward

Abstract

Background: Iron deficiency (ID) is an important comorbidity in patients with chronic heart failure (CHF). Either absolute or functional, ID is an independent predictor of outcomes, even in the absence of anemia. Functional iron deficiency (FID) is defined as an inadequate iron supply when iron stores are replenished and it is present whenever the ferritin level is between 100-299mg/L and transferrin saturation is lower than 20%. Iron supplementation in patients with FID improves clinical symptoms and reduces the risk of hospitalization due to decompensated CHF. Several studies have shown that iron deficiency is associated with an impaired humoral and cell mediated immunity, thereby contributing to an increased risk of infections. Despite this, iron deficiency is still overlooked in daily clinical practice and guidelines are frequently not followed in the "real world". Method(s): Retrospective analysis of patients with heart failure admitted to an Internal Medicine ward in the period of one year (August 2015 - August 2016). Purpose(s): To determine if there is any relationship between iron deficiency, iron supplementation and infection susceptibility in patients with CHF. Result(s): 225 patients were included in the analysis. 201 (89%) were admitted due to decompensated cardiac insufficiency, and of these 133 (59%) had iron deficiency (ID), which in turn was functional in 43% (n=57) of cases and absolute in 57% (n=76). In patients with FID, the average ferritin value was 176,7mg/L, with an average transferrin saturation of 14,3%; iron therapy was administered in only 33% (n=19) of cases. Time of admission for both cohorts was 16,2 days in patients with FID and 14,9 days in the ones with absolute ID; there was no significant difference between the two groups. Regarding the incidence of infections, 71% (n=49) of the patients with FID had at least one infection, whereas only 67% (n=62) of the patients without FID were infected. Respiratory infections were the most common (46%), followed by urinary tract infections (28%); in 20% of patients more than one infection occurred during hospitalization. Patients with decompensated HF had a significantly higher prevalence of FID (n=55, 27%) in comparison with patients without decompensated HF (n=2, 8%). However, there was no significant relationship between overall iron deficiency and the incidence of infection, X2 (2, N=225)=4,313, p=0,116. Additionally, in patients with FID there was no relationship between those who did iron therapy and the occurrence of infection, p=0,401, two-tailed Fisher's exact test, Cramer's V=0,111. Conclusion(s): Patients with CHF have a high incidence of functional iron deficiency. Whether the infection susceptibility is mainly due to the CHF itself or to the FID is difficult to differentiate, as FID cannot be seen as an independent factor from CHF. Iron deficiency might not be a relevant factor for infections in admitted patients due to the short period of time that is considered.