Definitions

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Iron Deficiency 

Iron deficiency develops when the amount of iron absorbed by the body does not meet the needs. It can arise either from an inadequate iron in the diet or from a number of different disease conditions that lead to increased iron loss or inadequate usage of iron. It can be considered a continuum, ranging from close to normal iron status, to iron deficiency without anaemia, to, in its most severe form, iron deficiency with anaemia.1^,2 Due to this, anaemia is often used as an indicator for iron deficiency. However, also in mild-to-moderate forms of iron deficiency, which have not yet progressed to anaemia, the tissues are lacking iron and are functionally impaired.2 The terms anaemia, iron deficiency and iron deficiency anaemia are sometimes, inappropriately, used interchangeably.2

Iron homeostasis can also be affected by chronic disease conditions and inflammation, which can block both the uptake of iron from the gut and the transport of iron. This state eventually leads to anaemia of chronic disease.3

Fatigue

Fatigue is a non-specific symptom, with many different causes. It is recognized as a multidimensional construct involving physical exhaustion, mental tiredness and a lack of energy.4 It is an important healthcare problem, as it is associated with disability comparable to that found in patients with chronic medical conditions5 such as chronic heart failure, chronic obstructive pulmonary disease and rheumatoid arthritis.4^,5^,6^,7^,8 Fatigue can have a powerful, adverse effect on quality of life and is considered a phenomenon with social, physiological and psychological dimensions.9

• 1. Okonko 2011 J Am Coll Cardiol. 2011;58(12):1241-1251. doi:10.1016/j.jacc.2011.04.040
• 2. a. b. c. WHO. Iron Deficiency Anemia. Assessment, Prevention, and Control. A Guide for Programme Managers. 2001.
• 3. Goodnough Transfusion. 2012 Jul;52(7):1584-92. doi: 10.1111/j.1537-2995.2011.03495.x. Epub 2011 Dec 29.
• 4. a. b. Radbruch L, Sabatowski R, Elsner F et al. Validation of the German version of the brief fatigue inventory. J Pain Symptom Manage 2003;25:449–458.
• 5. a. b. Lewis G, Wessely S. The epidemiology of fatigue: more questions than answers. J Epidemiol Community Health 1992;46:92–97.
• 6. Bergner M, Bobbitt R, Carter W et al. The Sickness Impact Profile: development and final revision of a health status measure. Med Care 1981;19:787–805.
• 7. Bowers S, Cannizzaro K, Gregus J et al. Outcomes in cardiopulmonary physical therapy: sickness impact profile. Cardiopulm Phys Ther J 2009;20:–19.
• 8. Witte KK, Clark AL. Why does chronic heart failure cause breathlessness and fatigue? Prog Cardiovasc Dis 2007;49:366–384.
• 9. Nijrolder I, van der Windt D, de Vries H et al. Diagnoses during follow-up of patients presenting with fatigue in primary care. CMAJ 2009;181:683–687.