Jones DEJ, Gray JC, Newton J
Institute of Cellular Medicine, Newcastle University, Newcastle, UK
Studies have established that levels of fatigue vary between different patient groups. It is less clear whether the nature, as opposed to severity of fatigue differs between groups.
To examine descriptions of fatigue by patients with a range of chronic diseases and determine the relationship between symptom domains.
Retrospective review of Fatigue Impact Scale (FIS) data.
Fatigue Research Group.
Six hundred subjects in five chronic disease groups and one (n=45) normal control group.
Main outcome measures
Statistical analysis was performed to assess the effect of increasing fatigue and the overlap of FIS domain scores between disease groups by calculation of geometric means as proportions summed to 1 in each FIS domains, whilst controlling for total score.
Those with lower scores exhibit relatively higher physical scores than patients with higher total scores. In contrast, as total score increases, so does the proportion accounted for by the cognitive and psychosocial scores. This was not related to a threshold effect as the maximum total score of 40 in the physical domain was only achieved in three patients (<1%). Average domain proportions between patient groups did not vary to any degree among physical (0.30–0.39), cognitive (0.15–0.23) and psychosocial (0.42–0.47) domain proportions of the patient groups.
Perceived fatigue is similar between patient groups. Increasing scores were not related to simply reaching the maximum threshold in the physical domain. Studies have confirmed a positive-structured approach to symptom management in one fatigue-associated chronic disease, primary biliary cirrhosis, leads to significant improvements in quality of life. We suggest that, with a similar approach, the same might be true in other chronic diseases where moderate fatigue is a significant problem.
Comment by ME Research UK
“Fatigue” is a disabling consequence of a wide range of chronic diseases; indeed, it was a main symptom of past outbreaks of ME, including the Royal Free Hospital outbreak in 1955, and its occurrence in conjunction with a constellation of symptoms forms the basis of present-day ME/CFS. But is the nature of fatigue different in different illnesses? Prof. Jones explored this issue by examining data from 600 people across 5 chronically ill disease groups; non-alcoholic fatty liver disease, vasovagal syncope, primary sclerosing cholangitis, primary biliary cirrhosis, and ME/CFS patients. Each patient had completed a generic Fatigue Impact Scale (FIS) from which scores on 3 subscales (physical, cognitive, and psychosocial) could be derived.
The overall conclusion was that the nature of patient-reported fatigue was similar between all 5 patient groups, suggesting that symptoms such as fatigue arise due to generic disease processes that chronic illnesses share. However, as regards severity, the 82 ME/CFS patients had much higher levels of total fatigue than any of the other patient groups (total FIS score 102, compared with the primary biliary cirrhosis group which was next highest at 41). This was reflected in higher subscale scores, since, as the researchers point out, the larger the direct impact of physical limitation, the greater are the subsequent knock-on effects on other aspects of higher cognitive and social functioning.
This is taken from the recent research section (pdf 519 KB) in the Autumn 2009 issue of Breakthrough.