Physical activity assessment in patients with axial spondyloarthritis compared to healthy controls: a technology-based approach.

INTRODUCTION: Traditionally, assessment in axial Spondyloarthritis (aSpA) includes the evaluation of the capacity to execute tasks, conceptualized as physical function. The role of physical activity, defined as movement-related energy expenditure, is largely unknown and almost exclusively studied using patient-reported outcome measures. The aims of this observational cross-sectional study are to compare physical activity between patients with aSpA and healthy controls (HC) and to evaluate the contribution of disease activity to physical activity differences between groups. METHODS: Forty patients with aSpA were matched by age, gender, period of data acquisition in terms of days and season to 40 HC. Physical activity was measured during five consecutive days (three weekdays and two weekend days) using ambulatory monitoring (SenseWear Armband). Self-reported disease activity was measured by the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). Differences in physical activity between patients with aSpA and HC were examined with Wilcoxon signed-rank tests and a mixed linear model. Difference scores between patients and HC were correlated with disease activity. RESULTS: Average weekly physical activity level (Med(IQR); HC:1.54(1.41-1.73); aSpA:1.45(1.31-1.67),MET) and energy expenditure (HC:36.40(33.43-41.01); aSpA:34.55(31.08-39.41),MET.hrs/day) were significantly lower in patients with aSpA. Analyses across intensity levels revealed no significant differences between groups for inactivity and time spent at light or moderate physical activities. In contrast, weekly averages of vigorous (HC:4.02(1.20-12.60); aSpA:0.00(0.00-1.20),min/d), very vigorous physical activities (HC0.00(0.00-1.08); aSpA:0.00(0.00-0.00),mind/d) and moderate/(very)vigorous combined (HC2.41(1.62-3.48); aSpA:1.63(1.20-2.82),hrs/d) were significantly lower in patients with aSpA. Disease activity did not interact with differences in physical activity between patients with aSpA and HC, evidenced by non-significant and very low correlations (range: -0.06-0.17) between BASDAI and HC-aSpA patients' difference scores. CONCLUSIONS: Patients with aSpA exhibit lower physical activity compared to HC and these differences are independent of self-reported disease activity. Further research on PA in patients with aSpA should be prioritized.

Assessment of physical activity and inactivity in multiple domains of daily life: a comparison between a computerized questionnaire and the SenseWear Armband complemented with an electronic diary.

BACKGROUND: Although differences between paper-and-pencil questionnaires and accelerometers have been reported for overall physical activity and time spent in moderate and vigorous activity, few studies have looked at domain-specific behavior. This study compared estimates of domain-specific physical (in)activity obtained with the Flemish physical activity computerized questionnaire (FPACQ) with those obtained from a combination of the SenseWear Armband and an electronic diary. Furthermore, it was investigated whether the correspondence between the two methods varied with gender and age. METHODS: Data were obtained from 442 Flemish adults (41.4 ± 9.8 years). Physical activity was questioned with the FPACQ and measured for seven consecutive days using the SenseWear Armband together with an electronic activity diary (SWD). Analogous variables were calculated from the FPACQ and SWD. Mean differences and associations between FPACQ and SWD outcomes were examined with paired t-tests and Pearson correlations. The Bland-Altman method was used to assess the level of agreement between the two methods. Main effects and interaction of gender and age groups (20-34; 35-49; 50-64 years) on differences between FPACQ and SWD outcomes were analyzed using two-way ANOVAs. RESULTS: All parameters of the FPACQ were significantly correlated with SWD assessments (r = 0.21 to 0.65). Reported activity was significantly different from SWD-obtained values for all parameters, except screen time. Physical activity level, total energy expenditure and time spent in vigorous activities were significantly higher (+0.14 MET, +25.09 METhours·week(-1) and +1.66 hours·week(-1), respectively), and moderate activities and sedentary behavior significantly lower (-5.20 and -25.01 hours·week(-1), respectively) with the FPACQ compared to SWD. Time and energy expenditure of job activities and active transport were significantly higher, while household chores, motorized transport, eating and sleeping were significantly lower with the FPACQ. Time spent in sports was lower (-0.54 hours·week(-1)), but energy expenditure higher (+4.18 METhours·week(-1)) with the FPACQ. The correspondence between methods varied with gender and age, but results differed according to the intensity and domain of activity. CONCLUSIONS: Despite the moderate correlations, significant differences between the two methods were found. In general, physical activity was higher and sedentary behavior lower as calculated from the FPACQ compared to SWD.