Measurement of physical activity in cancer survivors: a validity study

Abstract

The purpose of the study was to validate the Taiwanese version of the Physical Activity Scale for the Elderly (PASE-T) and to assess physical activity in Taiwanese cancer survivors. One hundred twenty-seven cancer survivors participated in this study. Instruments consisted of the PASE-T, the Taiwanese version of the MD Anderson Symptom Inventory (MDASI-T), Karnofsky performance status (KPS), and actigraph. Reliability was assessed by calculating the test-retest reliability. The validity was assessed by the content validity, criterion-related validity, convergent validity, and known-group validity. The test-retest reliability of PASE-T was 0.90 over a 2-week interval, based on a sample of 30 patients. The content validity index was very acceptable at 0.91. Convergent validity was demonstrated by its significant association with MDASI-T scores (symptom severity: r = -0.23, p = 0.001; symptom interference: r = -0.21, p = 0.001) and KPS scores (r = 0.59, p < 0.001). Criterion-related validity was established by a significant relationship to the actigraph total counts per minute (r = 0.64, p < 0.001). Known-group validity was established by its ability to detect significant differences according to a patient's performance status. Moreover, KPS (β = 0.37), fatigue (β = -0.32), and age (β = -0.20) were significant predictors of physical activity (R(2) = 0.46). The PASE-T is a reliable and valid instrument for measurement of physical activity among cancer survivors in Taiwan. This scale could be a useful measure of physical activity in cancer survivors and subsequently facilitate the quality of oncology care.