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Chronic Anemia

  • Author: Christopher D Braden, DO; Chief Editor: Barry E Brenner, MD, PhD, FACEP  more...
Updated: Feb 01, 2016


Anemia is defined as an absolute reduction in the quantity of the oxygen-carrying pigment hemoglobin (Hgb) in the circulating blood. Anemia is further broadly subcategorized into acute and chronic. (See Etiology.)

Anemia usually is grouped into 3 etiologic categories: decreased red blood cell (RBC) production, increased RBC destruction, and blood loss.

Anemia is a manifestation of an underlying disease process and is not a diagnosis in itself. A wide array of diseases, including inflammations, infections, and malignancies, may at some point be associated with anemia. Common conditions associated with anemia include the following:

  • Gastritis
  • Gastric or duodenal ulcer
  • Liver or renal disease
  • Hypothyroidism
  • Sickle cell disease
  • Hypermenorrhea
  • Previous history of anemia or blood transfusions
  • Thrombocytopenia or blood coagulation disorders
  • Cancer or other chronic illness (eg, rheumatic disease)
  • Poor diet, especially iron deficiency

A disease may lead to anemia through a combination of mechanisms. For example, a GI malignancy may cause anemia through blood loss, as well as lead to anemia of chronic disease. (See Etiology.)

Go to Anemia and Pediatric Chronic Anemia for complete information on these topics.

Patient Education

For patient education information, see Anemia.



Microcytic hypochromic anemia

Possible causes of this condition include iron deficiency, thalassemia, sideroblasts, and lead poisoning.

Anemia of chronic disease commonly is manifested by normocytic normochromic indices; however, microcytic hypochromic indices also can be associated with anemia of chronic disease.

Macrocytic anemia

Possible causes of macrocytic anemia include vitamin B-12 deficiency, folate deficiency, liver disease, and hypothyroidism.

Normocytic anemia

Normocytic anemia is further divided into 2 broad categories: anemia with primary bone marrow involvement and anemia secondary to underlying disease.

Anemias with primary bone involvement include aplastic anemia and myelophthisic anemia.

The etiology of myelophthisic anemia involves interruption of normal hematopoiesis due to the accumulation of malignant or reactive cells or cell products. It is characterized by the appearance of immature myeloid cells and nucleated RBCs in the peripheral blood. The 3 major classes of disorders that can produce myelophthisic anemia are intrinsic bone marrow malignancies (eg, leukemia, lymphoma, myeloma), metastatic tumors (eg, neuroblastoma, melanoma), cancers that are more prone to bone marrow metastasis (eg, prostate, breast, lung, stomach, renal carcinomas), and granulomatous disease (eg, tuberculosis, sarcoidosis).

Agnogenic myeloid metaplasia, which is characterized by anemia with primary bone marrow involvement, involves gradual bone marrow fibrosis, extramedullary hematopoiesis, and splenomegaly with no known underlying systemic disorder.

Most cases of anemia in the world are secondary to an underlying disease. The marrow does not respond appropriately to microcytic anemia, leading to decreased production of RBCs. This type of anemia includes that associated with liver cirrhosis, uremia, chronic inflammation, and hypoendocrine conditions (eg, thyroid, adrenal, pituitary disorders).

Hemolytic anemia

This type of anemia includes sickle cell anemia, thrombotic thrombocytopenic purpura (TTP), hemolytic uremic syndrome, aortic valve prosthesis, disseminated intravascular coagulation (DIC), cold agglutinin disease, and paroxysmal cold hemoglobinuria (PCH).



Occurrence in the United States and internationally

The incidence of anemia mirrors the incidence of the underlying cause. Some published studies report the incidence of anemia to be 2-15% in the United States and Great Britain.

Anemia is far more common in underdeveloped countries than in the United States. The true incidence of anemia is difficult to define because of multiple factors (eg, patient population, geographic location, normal range reference, ability to adequately screen for the disease).

Among 292 children in a low-income community in the Dominican Republic, 69.9% were found to be anemic using the World Health Organization (WHO)–recommended hemoglobin cut point of <11.0 g/dl, and 34.6% were classified as anemic using a cut point of <10.0 g/dl. The prevalence of microcytosis in anemic children ranged from 23.5% to 80.2%, depending on the hemoglobin and age-based mean corpuscular volume cut points used.[1]

Race-, sex-, and age-related demographics

African Americans have a higher incidence of sickle cell anemia and glucose-6-phosphate dehydrogenase (G-6-PD) deficiency. G-6-PD is essential for RBC protection from oxidative insults and for approximately 10% of RBC energy production.

Mediterranean populations show a higher incidence of beta thalassemia.

Sex distribution varies based on the underlying cause. Overall, females have approximately twice the incidence of males of anemia.

Anemia is prevalent in all age groups. Some younger patients may have a better ability to compensate for anemia, which may delay initial diagnosis.



Prognosis is dependent on several factors. The underlying medical condition usually dictates the prognosis, but comorbid conditions, the chronicity of the disease, and the patient’s diet, age, and access to medical care are contributing factors.


The majority of complications in chronic anemia arise from chronic or persistent tissue hypoxia.

Pediatric patients, elderly patients, and patients who are immunocompromised are at the highest risk for complications, since they have less physiologic reserve.

Failure to comply with follow-up and treatment regimens predisposes patients with chronic anemia to complications.

Contributor Information and Disclosures

Christopher D Braden, DO Hematologist/Oncologist, Chancellor Center for Oncology at Deaconess Hospital

Disclosure: Nothing to disclose.


Eric Wilke, MD Medical Director, Traditions Emergency Medicine, College Station Medical Center

Eric Wilke, MD is a member of the following medical societies: American College of Emergency Physicians, Texas Medical Association

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Jeffrey L Arnold, MD, FACEP Chairman, Department of Emergency Medicine, Santa Clara Valley Medical Center

Jeffrey L Arnold, MD, FACEP is a member of the following medical societies: American Academy of Emergency Medicine, American College of Physicians

Disclosure: Nothing to disclose.

Chief Editor

Barry E Brenner, MD, PhD, FACEP Professor of Emergency Medicine, Professor of Internal Medicine, Program Director for Emergency Medicine, Case Medical Center, University Hospitals, Case Western Reserve University School of Medicine

Barry E Brenner, MD, PhD, FACEP is a member of the following medical societies: Alpha Omega Alpha, American Heart Association, American Thoracic Society, Arkansas Medical Society, New York Academy of Medicine, New York Academy of Sciences, Society for Academic Emergency Medicine, American Academy of Emergency Medicine, American College of Chest Physicians, American College of Emergency Physicians, American College of Physicians

Disclosure: Nothing to disclose.

Additional Contributors

Roy Alson, MD, PhD, FACEP, FAAEM Associate Professor, Department of Emergency Medicine, Wake Forest University School of Medicine; Medical Director, Forsyth County EMS; Deputy Medical Advisor, North Carolina Office of EMS; Associate Medical Director, North Carolina Baptist AirCare

Roy Alson, MD, PhD, FACEP, FAAEM is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, World Association for Disaster and Emergency Medicine, National Association of EMS Physicians, Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.


The authors and editors of Medscape Reference gratefully acknowledge the contributions of previous author Fredrick Melik Abrahamian, DO, FACEP,to the development and writing of the source article.

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