Background It is well recognised that many health benefits, in particular cardiovascular benefits, are associated with an active lifestyle (Bauman, 2004). Those with RA are at an increased risk of mortality related to cardiovascular events (Avina-Zubieta et al, 2008; Solomon et al, 2003); therefore an active lifestyle in this population is especially necessary. In order to measure physical activity (PA) in large scale epidemiological studies of the RA population, a quick, economical, accurate and subject friendly tool needs to be utilised. Although the SWA is subject friendly, relatively quick in producing results and valid to measure PA in this population (Tierney et al, 2011), its cost at €800 (ex VAT) per unit may limit its usefulness in large scale epidemiological trials.
Objectives To determine the correlation between SWA and IPAQ in measuring PA in people with RA.
Methods Twenty-five subjects with a diagnosis of RA (ACR criteria) were recruited from rheumatology clinics at the Mid Western Regional Hospitals, Limerick, Ireland. Full ethical approval was received and subjects gave written informed consent. Subjects wore a SWA on the back of the right upper arm. Subjects returned the monitors after 7 full days of recording and completed the short form IPAQ. SWA output was analysed in the form of total energy expenditure (EE), 10 hour EE and BMI adjusted total and 10 hour EE. IPAQ output was analysed in the form of MET-minutes per week and Sitting Time. Analyses were performed using PASW version 18.0 (Chicago, IL). Normality testing was performed on all data and data was transformed as necessary. Correlational analysis was performed using both parametric (Pearson’s) and non-parametric (Spearman’s rho) methods.
Results No large (>0.6) (Hemphill, 2003) correlations were determined between any aspect of the SWA and any aspect of the short form IPAQ. The Sitting Time aspect of the short form IPAQ performed better than the MET-minutes per week aspect with a correlation of 0.538 between BMI adjusted total EE and Sitting Time. The Sitting Time aspect of the IPAQ also achieved correlations of >0.4 with five other SWA variables.
Conclusions Sitting Time shows a stronger correlation than MET-minutes per week to the validated SWA. However, none of these correlations were strong enough to be considered large. Further large scale studies are necessary before the IPAQ can be used as a measure of physical activity in the RA population.
Bauman, AE. Updating the evidence that physical activity is good for health: an epidemiological review 2000-2003. Journal of Science and Medicine in Sport, 2004; 7, 6-19.
Aviña-Zubieta, JA, Choi, HK, Sadatsafavi, M, Etminan, M, Esdaile, JM Lacaille, D. Risk of cardiovascular mortality in patients with rheumatoid arthritis: A meta-analysis of observational studies. Arthritis Care Res, 2008; 59, 1690-1697.
Solomon, DH, Karlson, EW, Rimm, EB, Cannuscio, CC, Mandl, LA, Manson, JE, Stampfer, MJ Curhan, GC. Cardiovascular Morbidity and Mortality in Women Diagnosed With Rheumatoid Arthritis. Circulation, 2003; 107, 1303-1307.
Tierney, M, Fraser, AD, Kennedy, NM. Validity of SenseWear Armband to Estimate Energy Expenditure During Activities of Daily Living In Rheumatoid Arthritis. [abstract]. Arthritis Rheum 2011;63 Suppl 10: 2419.
Hemphill, JF. Interpreting the magnitudes of correlation coefficients. Am Psychol, 2003; 58(1), 78-79.
Disclosure of Interest None Declared
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