RT Journal Article
SR Electronic
T1 Can the Cancer-related Fatigue Case-definition Criteria Be Applied to Chronic Medical Illness? A Comparison between Breast Cancer and Systemic Sclerosis
JF The Journal of Rheumatology
JO J Rheumatol
FD The Journal of Rheumatology
SP 1156
OP 1162
DO 10.3899/jrheum.141421
VO 42
IS 7
A1 Linda Kwakkenbos
A1 Ollie Minton
A1 Patrick C. Stone
A1 Susanna Alexander
A1 Murray Baron
A1 Marie Hudson
A1 Brett D. Thombs
A1 and the Canadian Scleroderma Research Group
YR 2015
UL http://www.jrheum.org/content/42/7/1156.abstract
AB Objective. Fatigue is a crucial determinant of quality of life across rheumatic diseases, but the lack of agreed-upon standards for identifying clinically significant fatigue hinders research and clinical management. Case definition criteria for cancer-related fatigue were proposed for inclusion in the International Classification of Diseases. The objective was to evaluate whether the cancer-related fatigue case definition performed equivalently in women with breast cancer and systemic sclerosis (SSc) and could be used to identify patients with chronic illness-related fatigue.Methods. The cancer-related fatigue interview (case definition criteria met if ≥ 5 of 9 fatigue-related symptoms present with functional impairment) was completed by 291 women with SSc and 278 women successfully treated for breast cancer. Differential item functioning was assessed with the multiple indicator multiple cause model.Results. Items 3 (concentration) and 10 (short-term memory) were endorsed significantly less often by women with SSc compared with cancer, controlling for responses on other items. Omitting these 2 items from the case definition and requiring 4 out of the 7 remaining symptoms resulted in a similar overall prevalence of cancer-related fatigue in the cancer sample compared with the original criteria (37.4% vs 37.8%, respectively), with 97.5% of patients diagnosed identically with both definitions. Prevalence of chronic illness-related fatigue was 36.1% in SSc using 4 of 7 symptoms.Conclusion. The cancer-related fatigue criteria can be used equivalently to identify patients with chronic illness-related fatigue when 2 cognitive fatigue symptoms are omitted. Harmonized definitions and measurement of clinically significant fatigue will advance research and clinical management of fatigue in rheumatic diseases and other conditions.