Purpose: Physical activity (PA) is an important outcome in lung cancer; however, there is lack of consensus as to the best method for assessment. The Physical Activity Scale for the Elderly (PASE) is a commonly used questionnaire. The aim of this study was to assess the clinimetric properties of the PASE in lung cancer, specifically validity, predictive utility and clinical applicability (floor/ceiling effects, responsiveness and minimal important difference [MID]).
Methods: This is a prospective observational study. Sixty-nine participants (62 % male, median [IQR] age 68 years [61-74]) with lung cancer completed the PASE at diagnosis at 2, 4 and 6 months. Additional measures included movement sensors (steps/day), physical function, health-related quality of life, functional capacity (6-min walk distance [6MWD]), and muscle strength. Spearman's rank correlation coefficient was used to assess relationships. Linear regression analyses were conducted to determine predictive utility of the PASE for health status at 6 months. Responsiveness (effect size) and MID (distribution-based estimation) were calculated.
Results: The PASE was administered on 176 occasions. The PASE had moderate convergent validity with movement sensors (rho = 0.50 [95 %CI = 0.29-0.66], p < 0.005) and discriminated between participants classed as sedentary/insufficient/sufficient according to PA guidelines (p < 0.005). The PASE had fair-moderate construct validity with measures of physical function (rho = 0.57 [95 %CI = 0.46-0.66], p < 0.005), 6MWD (rho = 0.40 [95 %CI = 0.23-0.55], p < 0.005), and strength (rho = 0.37 [95 %CI = 0.18-0.54], p < 0.005). The PASE (at diagnosis) exhibited predictive utility for physical function (Bcoef = 0.35, p = 0.008) and quality of life (Bcoef = 0.35, p = 0.023) at 6 months. A small floor effect was observed (3 %); however, there was no ceiling effect. There was a small responsiveness to change (effect size = 0.23) and MID between 17 and 25 points.
Conclusions: The PASE is a valid measure of self-reported PA in lung cancer.
Keywords: Clinimetric properties; Lung cancer; Physical activity; Questionnaires; Self-report.