Purpose/objectives: To confirm the multidimensionality of the Piper Fatigue Scale (PFS) and to reduce the total number of PFS items without compromising reliability and validity estimates.
Design: Methodologic, part of a larger, cross-sectional, mailed survey design study.
Setting: Urban and suburban area in the northeast United States.
Sample: As part of the larger study, 2,250 surveys were distributed to women survivors of breast cancer who were on a mailing list for the educational organization Living Beyond Breast Cancer, 715 surveys (32%) were returned. Of these, 382 women met this methodologic study's criteria for having completed each of the 40 items on the PFS. The average respondent was 50 years old, postmenopausal, and treated with combination cancer therapy.
Methods: Principal axes factor analysis with oblique rotation.
Main research variables: Fatigue factors/subscales.
Findings: Five factors/subscales were identified initially. Because the fifth factor contained only two items (ability to bathe/wash and ability to dress), these items and the associated factor/subscale were dropped from the final solution. An additional nine items, not loading on any factor (> 0.40), also were dropped. The remaining items and factors/subscales were reviewed to ensure that the criteria were met: a pattern of inter-item correlations between 0.30-0.70; a minimum number of five or more items/subscale; standardized alpha for the subscales and total scale of at least 0.89; and absence of gender-specific items.
Conclusions: The revised version of the PFS consists of 22 items and four subscales: behavioral/severity (6 items), affective meaning (5 items), sensory (5 items) and cognitive/mood (6 items). Standardized alpha for the entire scale (n = 22 items) is 0.97, indicating that some redundancy still may exist among the items. Additional revisions await further testing.
Implications for nursing practice: As fatigue is acknowledged to be the most frequent symptom experienced by patients with cancer, accurate measurement and assessment is essential to advance not only the science of fatigue but, most importantly, to evaluate the efficacy of intervention strategies on patient and family outcomes.