Validation of two self-reported physical activity instruments against accelerometer data in patients undergoing lung cancer surgery.

INTRODUCTION Finding ways of identifying patients with low levels of physical activity after lung cancer surgery would be beneficial when planning and providing interventions aimed at increasing physical activity. PURPOSE To validate two self-reported physical activity instruments against accelerometer data. METHODS Self-reported physical activity was assessed with the four category One Month Physical Activity Question (OMPAQ) and the International Physical Activity Questionnaire modified for the elderly (IPAQ-E). Objective measurement of physical activity was performed with the Actigraph GT3X+ accelerometer. All measurements were performed three months after lung cancer surgery. RESULTS Three months after surgery, 83 patients provided complete physical activity measurements. There were statistically significant correlations between both of the self-reported physical activity assessed by OMPAQ (r = 0.54, p < .01) as well as IPAQ-E (r = 0.50, p < .01) and objectively measured physical activity (steps/day). The correlations were consistently stronger for the higher intensities of physical activity. Both instruments could identify patients not reaching the recommended levels of physical activity. CONCLUSION Both OMPAQ and IPAQ-E give valid information on physical activity after lung cancer surgery, and might be used for screening patients in clinical settings. The OMPAQ provided stronger correlation and specificity than the IPAQ-E, and might be the preferred clinical choice.