Objectives: To compare levels of physical activity (PA) assessed by the International Physical Activity Questionnaire (IPAQ) with PA measured with the SenseWear Pro Armband (SWA) in women with fibromyalgia, and to assess the test-retest reliability of the IPAQ.
Methods: The study comprised a total of 183 women with fibromyalgia aged 51.1±8.2 years. Participants wore the SWA for 9 consecutive days and filled in the IPAQ twice (separated by a 9-day interval). Total PA, time spent on moderate and vigorous intensity PA, and sitting time assessed by the IPAQ and the SWA (n=123) were compared.
Results: Time spent on PA at different intensities (total, moderate and vigorous) was higher and sedentary time was lower when assessed by the IPAQ compared with the SWA (all p<0.001). Differences between the IPAQ and the SWA increased as the minutes per day in the IPAQ increased. The Bland-Altman plots showed no agreement between the IPAQ and the SWA. There was no association between the IPAQ and the SWA in any of the variables studied, except for walking domain from the IPAQ and moderate PA from the SWA (rp=0.19, p=0.03). Test-retest systematic differences were found for total PA score, moderate and vigorous intensity, working and domestic domains (all p<0.05). The ICCs for those domains without systematic differences (sitting, vehicle, walking, active transport time and leisure domains) ranged from 0.52 to 0.71).
Conclusions: The IPAQ differs from objectively measured PA and presents limitations to classify different categories of PA based on SWA data. Moreover, the IPAQ is not a reliable tool to assess PA in women with fibromyalgia.