Development of the functional capacity screening tool (FCST): A brief instrument to identify functional capacity deficits in anemic cancer patients

Abstract

8593 Background: Existing fatigue measures are long and often difficult to incorporate in practice. The objective of this study was to develop a short tool (Functional Capacity Screening Tool [FCST]) to identify functional capacity deficits related to fatigue in anemic cancer patients (pts) using self-report and performance-based measures of functional capacity. Methods: Data were obtained from a multicenter, open-label, single-arm study of darbepoetin alfa therapy (3.0 μg/kg every 2 weeks) in cancer pts (n=1558) who were ≥ 18 years of age with nonmyeloid malignancies receiving cyclic chemotherapy and anemia (hemoglobin [Hb] ≤ 11 g/dL). The Modified Harvard Step Test (MHST) was used as a performance-based measure of functional capacity to assess adjusted VO2max. Pts who contributed data for the development of FCST completed the following: MHST, baseline and ≥ 1 follow-up Hb measurement, baseline and ≥ 1 follow-up Functional Assessment of Cancer Therapy-Fatigue (FACT-F), and fatigue assessed within 3 days of MHST. Items from FACT-F, Brief Fatigue Inventory (BFI), Fatigue Symptom Inventory (FSI) and Medical Outcomes Study physical functioning scale were tested for inclusion in the FCST. Individual item scores were transformed to a 100-point scale. Item selection was based on identifying best predictors of adjusted VO2max, Hb, and global FACT-F scores using linear regression and the r-square selection method. FCST scores were calculated by summating item scores and dividing by number of items. Results: Data from401 pts contributed to the development of the FCST. Eight items were identified for the FCST with a Cronbach’s coefficient alpha of 0.92. Construct validity was supported by correlations of FCST with FSI (r = 0.80, P < .0001) and BFI (r = 0.86, P < .0001). Correlations between FCST and energy (r = 0.75, P < .0001), productivity (r = 0.72, P < .0001), and Hb (r = 0.24, P < .0001) further supported construct validity. Conclusions: FCST holds promise as a short screening tool for identifying functional capacity deficits in cancer pts. This new instrument was reliable, easy to score, and completed quickly by pts, making it suitable for incorporation in clinical practice. Further validation is required in different cancer populations. [Table: see text]