Abstract
INTRODUCTION: No tool currently used by primary health care providers to assess physical activity has been evaluated for its ability to determine whether or not patients achieve recommended levels of activity. The purpose of this study was to assess concurrent validity of physical activity self-reported to the brief (<30 sec) Physical Activity "Vital Sign" questionnaire (PAVS) compared with responses to the lengthier (3-5 min), validated Modifiable Activity Questionnaire (MAQ). METHODS: Agreement between activity reported to the PAVS and MAQ by primary care patients at 2 clinics in 2014 was assessed by using percentages and κ coefficients. Agreement consisted of meeting or not meeting the 2008 Aerobic Physical Activity Guidelines for Americans (PA Guidelines) of the US Department of Health and Human Services. We compared self-reported usual minutes per week of moderate-to-vigorous physical activity among patients at a primary care clinic in 2014 who reported to PAVS and to MAQ by using Pearson correlation and Bland-Altman plots of agreement. RESULTS: Among 269 consenting patients who reported physical activity, PAVS results agreed with those of MAQ 89.6% of the time and demonstrated good agreement in identifying patients who did not meet PA Guidelines recommendations (κ = 0.55, ρ = 0.57; P < .001). Usual minutes per week of moderate-to-vigorous physical activity reported to PAVS had a high positive correlation with the same reported to MAQ (r = 0.71; P < .001). CONCLUSION: PAVS may be a valid tool for identifying primary care patients who need counseling about physical activity. PAVS should be assessed further for agreement with repeated objective measures of physical activity in the patient population.