The Relationship Between Subjective and Objective Methods for Measuring Physical Activity Status of Axial Spondyloarthritis Patients: Questionnaire Versus Accelerometer

Background: Physical activity is getting more attention for the appropriate management of both disease itself and co-morbid conditions in patients with axial spondyloarthritis (axSpA). Many different tools are available for determining physical activity status. Although subjective tools such as questionnaires are quick and easy for gathering data, objective tools such as accelerometers might provide more accurate information.

Objectives: To investigate the relationship between a subjective physical activity questionnaire (International Physical Activity Questionnaire Short Form: IPAQ) and an accelerometer (Actigraph wGT3X-BT) for measuring physical activity status of axSpA patients.

Methods: Thirty-nine patients with axSpA (age 37.9±11.3 years, body mass index 26.9±5.3 kg/m2, disease activity: 3.3±2.3 according to Bath Ankylosing Spondylitis Disease Activity Index, functional status: 2.9±2.8 according to Bath Ankylosing Spondylitis Functional Activity Index, 24 male) according to ASAS criteria were included to assess the subjective and objective physical activity status by using the Turkish version of IPAQ and an accelerometer (Actigraph wGT3X-BT), respectively. The accelerometer was worn by the patients on their waists at their first visit and it provides information about the light, moderate, vigorous physical activity times in minutes. On the seventh day when the accelerometer was removed, patients were asked to complete the IPAQ. The IPAQ inquires the physical activity performed previous week in minutes and categorizes into three sections as vigorous, moderate activity, and walking. The walking section in IPAQ was accepted as equal to light physical activity in Actigraph. The relationship between measurements was determined by using Spearman’s Rank Correlation Coefficient

Results: No significant correlations were determined between subjective and objective methods (p>0.05), except the time spent during moderate physical activity (rho: 0.457, p<0.05). It was also observed that IPAQ were underestimating the physical activity times for all types of physical activity.

Conclusion: According to our results, IPAQ short version may not be an appropriate tool for determining physical activity status in axSpA patients. It seems that we need disease specific tools in axSpA.