Abstract 21453: Disordered Iron Homeostasis in Chronic Heart Failure and its Relation to Anemia, Exercise Capacity and Survival
Background: Iron deficiency is an emerging therapeutic target in chronic heart failure (CHF). To date, no analysis has comprehensively delineated iron metabolism and its ramifications in this cohort.
Methods: We prospectively quantified circulating (e.g transferrin saturation [TSAT]), stored (e.g ferritin), and functional (e.g mean cell Hb concentration [MCHC]) iron indices in 157 consecutive CHF (age 71±12y, 55% NYHA 3/4, LVEF 32±9%, Hb 13±2g/dL) patients (pts) and 21 age- and sex-similar controls.
Results: First, TSAT (P<0.0001), MCHC (P<0.0001), but not ferritin (P=0.1), levels declined from controls to NYHA 1/2, 3 and 4 pts. Within each NYHA strata, anemic pts had lower TSATs and MCHCs than non-anaemic pts (all p<0.05). Second, while iron overload and elevated iron stores were rare (1%), 44% of pts were iron deficient (TSAT<20%). Third, reductions in TSAT related to worsening CRP (r=0.48) and NYHA class (r=0.50), and significantly predicted lower Hbs (r=0.58) independently of age, ESR, NYHA class and creatinine. Fourth, the etiologies of anemia varied with disease severity with anemia of chronic disease (ACD) and/or iron deficiency anemia (IDA) evident in 16%, 72% and 100% of anemic NYHA class 1/2, 3 and 4 pts. Pure ACD (27%) was commoner than pure IDA (17), but both conditions co-existed in 17% of pts. Fifth, lower TSATs related to lower peak oxygen consumptions (r=0.71) and ventilatory efficiency (r= −0.43). Finally, over a median (± IQR) follow-up of 743 (± 304) days, 27 patients (17%) died. Iron deficiency (HR 3.38, 95% CI 1.48 to 7.72, p=0.004, Figure A), predicted increased mortality independently of NYHA class, β-blocker use, Hb, and creatinine. Non-anemic iron deficiency pts had a 2-fold greater risk of death than anemic iron-replete subjects (Figure B).
Conclusions: Disordered Iron homeostasis in chronic heart failure relates to impaired exercise capacity and survival and appears prognostically more ominous than anemia. Survival trials are needed.
- © 2010 by American Heart Association, Inc.