When your body has lower red blood cell and carrying fewer oxygen to the tissue then this condition is called Anemia. In this situation the tissues got less oxygen specially the brain and the heart.
Anemia mostly occur to the people who is suffering from Chronic Kidney Disease (CKD). Other common causes of Anemia of Kidney patients are loss blood due to hemodialysis and lower nutrients in food like iron, folic acid , vitamin B12 etc . These nutrients are necessary to generate red blood cells.