Health and Quality of Life Outcomes

A large number of fatigue scales exist and there is no consensus on which fatigue measuring scales that are most appropriate for use in assessment of fatigue in different diseases. We aimed to describe the use of fatigue scales in studies of disease-related fatigue during the last three decades. We searched databases from 1975 to 2004 for original studies reporting on disease-related fatigue and extracted information on method used to assess fatigue, diseases under study and year of publication. A total of 2285 papers reported measures of fatigue in chronic non-acute diseases of which 80% were published during the last decade. We identified 252 different ways to measure fatigue, of which 150 were use only once. Multi-symptom scales (n = 156) were used in 670 studies, while 71 scales specifically designed to measure fatigue were applied in 416 studies. The majority of these studies used scales with a multidimensional approach to fatigue, and most studies used scales that were disease-specific or only applied to few different diseases. Research in diseaserelated fatigue has increased exponentially during the last three decades, even if we adjust for the general increase in publishing activity. The number of scales has also increased and the majority of scales were developed for specific diseases. There is need for measure instruments with different sizes and dimensionality, and due to ceiling and floor effects, the same scale may not be useful for patients with different severity of fatigue. However, since fatigue is an unspecific symptom there should not be need for adopting disease specific fatigue scales for each individual disease. There may be differences in characteristics of fatigue between diseases and generic measurement instruments may facilitate documentation of such differences, which may be of clinical importance. Review Fatigue may be a clinically important, although subjective and quite unspecific characteristic of some chronic diseases, and major textbooks list diseases from different medical specialities like multiple sclerosis, heart failure, liver disease, adrenal insufficiency, anemia, renal failure, thyrotoxicosis, systemic lupus erythematosus, and any malignant disease [1-3]. Fatigue is also a core symptom in depression [4]. Although we generally know little of etiology of fatigue, we do know that several biological factors exists, e.g. anemia and toxic treatment effects, as well as psychological factors. The word fatigue originate from the experience in healthy individuals, but interview based studies have revealed that even though patients label their sensation as fatigue, they often find it qualitatively very different from that fatigue they experienced before they Published: 27 February 2007 Health and Quality of Life Outcomes 2007, 5:12 doi:10.1186/1477-7525-5-12 Received: 24 November 2006 Accepted: 27 February 2007 This article is available from: http://www.hqlo. com/content/5/1/12 © 2007 Hjollund et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.