Anemia is when your body doesn't have enough red blood cells and hemoglobin -- a protein that helps red blood cells carry oxygen throughout your body. Anemia is a common problem in people with chronic kidney disease (CKD) for a few reasons.
You Don't Have the Hormones You Need to Make New Red Blood Cells
Every cell and organ in your body needs oxygen to work properly. Red blood cells carry that oxygen everywhere it needs to go.
Your red blood cells are constantly being recycled. Your body replaces the old red blood cells that die with healthy new ones.
Your body makes those new red blood cells in bone marrow -- the soft and spongy tissue inside your bones -- with some help from your kidneys. When your body is low in red blood cells, special cells inside your kidneys sense the drop in oxygen and release a hormone called erythropoietin (EPO). EPO signals your bone marrow to make more red blood cells.
CKD can damage your kidneys to the point where they no longer make enough EPO. When you're low in it, your bone marrow can't make as many red blood cells. If more red blood cells die than your bone marrow can replace, your body won't get as much oxygen.
Your Red Blood Cells Are Short-Lived
When you have CKD, the red blood cells you do have don't live as long in your bloodstream. Red blood cells normally live for 120 days. In people with CKD, they last for only 70 to 80 days. They may die before your body is ready to replace them, which creates a shortage.
You Don't Have Enough Iron and Other Nutrients
Your body needs iron to make red blood cells.
About half of people with late-stage CKD don't have enough iron. If you're one of them, it could be because:
- You get too little iron in your diet.
- Your body doesn't absorb iron well.
- You've lost blood from having frequent dialysis or blood tests.
When you lose blood, you lose iron, too.
CKD can also leave your body low in other nutrients that it needs to make healthy red blood cells, including vitamin B12 and folate (sometimes called vitamin B9).
Other Causes
More reasons people with CKD get anemia include:
- Infections
- Inflammatory chemicals called cytokines
- Malnutrition
Your chances of anemia with your CKD may go up if:
- You're female.
- You have diabetes.
- You're African American.
- Your kidneys don't work well or have failed.
If you have anemia, talk to your doctor about the reasons for it, and what you can do about it.