| Description |
Few instruments have been developed to assess patient physical activity (PA) in primary healthcare, nor assessed for validity. The purpose of these studies was to provide evidence of validity for a PA "vital sign" (PAVS) self-reported by clinic staff and patients and for the PA portion of the Speedy Nutrition and PA assessment (SNAP). Criterion validity of the PAVS and SNAP was assessed in clinic staff by agreement with accelerometry (accel). Construct validity of the PAVS was assessed by using electronic health records (EHRs) to examine odds of BMI and Charlson Comorbidity Index categories for patients reporting to the PAVS as not meeting 2008 Aerobic PA Guidelines for Americans (PAG) compared to patients meeting PAG. Concurrent validity of the PAVS was assessed by associating patient responses to the PAVS with concurrent responses to a Modifiable Activity Questionnaire (MAQ). The PAVS and SNAP correlated moderately strongly with accel identifying days/week clinic staff (N = 45) achieved ≥30 minutes (min) of moderate-vigorous PA (MVPA) performed at least 10 min. at a time (PAVS, r 0.52, p < 0.001; SNAP, r 0.31, p < 0.05). Of 34,712 eligible outpatient visits, patients who did not meet PAG according to the PAVS were more likely than normal weight patients to have a higher BMI (BMI 25.0-29.9, OR = 1.19, p = 0.001; BMI 30-34.9, OR = 1.39, p < 0.0001; BMI 35.0-39.9, OR = 2.42, p < 0.0001; BMI ≥ 40, OR = 3.7, p < 0.0001). Likewise, patients who did not meet PAG were also significantly more likely to have a higher disease burden (above 50th Charlson percentile, OR = 1.8, p < 0.0001). Of 269 eligible patient-participants, the PAVS agreed with the MAQ 89.6% of the time identifying insufficiently active patients and demonstrated good agreement with the MAQ identifying patients meeting/not meeting PAG (k = .55, rho = 0.57; p < 0.0001). Usual min·wk-1 MVPA reported to the PAVS correlated strongly with the same construct reported to the MAQ (r = 0.71; p < 0.0001). The PAVS appears to be a useful and valid tool particularly for identifying patients who most need counseling for PA. The PAVS should be evaluated further for validity and repeatability with criterion measures of PA. The PAVS could be used within EHRs to improve estimates of PA-disease relationships and interventions aimed to improve patient PA. |
