Purpose
To empirically determine clinically meaningful cut-scores on the 0–10 response scale of the revised Piper Fatigue Scale (PFS-R) and its shorter version (PFS-12). Breast cancer survivors were classified (i.e., none, mild, moderate, or severe fatigue) based on the cut-scores, and relationships between these cut-scores and decrements in health-related quality of life (HRQOL) were examined.
Methods
A total of 857 breast cancer survivors, stages in situ-IIIa, from the Health, Eating, Activity, and Lifestyle (HEAL) Study were eligible. Survivors completed the PFS-R, SF-36, and a sexual health scale approximately 3 years after diagnosis. Multivariate analysis of covariance was used to examine five fatigue severity cut-score models, controlling for demographics, clinical characteristics, comorbidity, and antidepressant use. Multivariate regression was used to examine HRQOL decrements by cut-score category.
Results
Analyses supported two similar fatigue severity cut-score models for the PFS-R and PFS-12: Model A.) none (0), mild (1–3), moderate (4–6), and severe (7–10); and Model D.) none (0), mild (1–2), moderate (3–5), and severe (6–10). For every threshold increase in fatigue severity, clinically meaningful decrements in physical, mental, and sexual health scores were observed, supporting construct validity of the fatigue cut-scores.
Conclusion
Standardized fatigue cut-scores may enhance interpretability and comparability across studies and populations and guide treating planning.
