Scientific status of fatigue and pain. Publishing and professional activities: 2002-2011

Background: Clinicians and researchers often deal with fatigue and pain in patients who are ill, and in healthy individuals. Purpose: To identify fatigue and pain publishing trends and professional activities over a recent decade in order to assess the scientific status of these domains. Methods: Peer review citations and professional activities for fatigue as compared to pain were tabulated for the decade, 2002-2011. Results: For the decade, fatigue represented 15% of citations, and pain, 85%. Annual publication frequencies fit an exponential model for fatigue (R squared=0.97; p<0.0001) and a linear model for pain (R squared=0.94; p<0.0001). The most common fatigue research categories were: "non-disease" (38%; e.g., fatigue in exercise, workers, healthy populations), medically unexplained fatigue (18.8%; primarily chronic fatigue syndrome/myalgic encephalomyelitis [CFS/ME]), and cancer fatigue (8%). No overarching theory of fatigue was identified. By comparison, the central sensitization model of pain has gained cross-disciplinary recognition. Although a scientific discipline of pain was evident, the field of fatigue studies lacks many of the elements (e.g., texts, accreditation programs) necessary for an established discipline. Conclusions: Although fewer articles were found for fatigue in comparison to pain, publishing rates for both domains increased by about 90% over the decade. The literature has begun to identify the importance of the symptom of fatigue.