Anemia is frequent in patients with heart failure. Few studies have clearly addressed the causes of anemia in patients with HF. The purpose of this study is to evaluate differences in blood concentrations of various substances related to inflammation, oxidative stress, renal function and other processes between individuals with 1) heart failure and anemia, 2) heart failure without anemia and 3) patients with kidney disease without systolic heart failure. This study will help to better understand the reasons why some people with heart failure have anemia.