A multidimensional measure of fatigue for use with cancer patients.

PURPOSE The purpose of this study was to develop and validate a multidimensional measure of fatigue for use with cancer patients. DESCRIPTION OF STUDY Items for the Multidimensional Fatigue Symptom Inventory (MFSI) were generated through literature review, discussion with healthcare providers, and a survey of currently available measures of fatigue. The 83-item MFSI was designed to assess global, somatic, affective, cognitive, and behavioral symptoms of fatigue. The instrument was administered on three occasions to 275 women who had received or were undergoing treatment for breast cancer and 70 women with no history of cancer. Reliability, validity, and factorial structure of the MFSI were analyzed. RESULTS The factor analysis produced five empirically derived scales that correspond generally to the five rationally derived scales. Reliability of the rationally and empirically derived scales was excellent (alpha coefficients .87 to .96). Estimates of test-retest reliability were also favorable. Other results support the validity of both the rationally and empirically derived scales. The MFSI appears to be sensitive to fatigue, accurately discriminating cancer patients from control subjects and between patients with varying levels of performance status. CLINICAL IMPLICATIONS The MFSI may be useful in identifying patterns of fatigue within individual patients and across treatment modalities. Such specificity may allow the clinician to develop, implement, and evaluate interventions that are targeted for differing patterns of fatigue. Because the measure is keyed to a 1-week time frame, it may be useful during the course of cancer treatment. The MFSI appears to be a valid and reliable tool to assess the full spectrum of symptoms that characterize the construct of fatigue.