Table 3.
Summary of Results Examining the Comparative Ability of SWm and AG3 Monitors to Differentiate between Observed Sedentary and Light Activities in a Laboratory Setting
| Mean (95% CI) |
|||||
|---|---|---|---|---|---|
| Statistic | SWm (A) | SWm (B) | AG3 VM<200 (A&B) | AG3 VA<25 (A&B) | AG3 VA<100 (A&B) |
| Sensitivity (0–1) | 0.98 (0.95, 0.99) | 0.89 (0.86, 0.93) | 0.99 (0.97, 0.99) | 0.99 (0.98, 0.99) | 0.99 (0.98, 0.99) |
| Specificity (0–1) | 0.71 (0.65, 0.77) | 0.61 (0.55, 0.67) | 0.47 (0.40, 0.53) | 0.33 (0.27, 0.40) | 0.27 (0.22, 0.33) |
| PPV (0–1) | 0.81 (0.77, 0.85) | 0.74 (0.70, 0.78) | 0.70 (0.65, 0.74) | 0.65 (0.62. 0.69) | 0.63 (0.59, 0.67) |
| NPV (0–1) | 0.96 (0.92, 0.95) | 0.82 (0.76, 0.87) | 0.99 (0.93, 0.99) | 0.99 (0.94, 0.99) | 0.99 (0.93, 0.99) |
| LR+ (≥1) | 3.40 (2.80, 4.10) | 2.29 (1.96, 2.68) | 1.86 (1.66, 2.08) | 1.48 (1.36, 1.61) | 1.37 (1.27, 1.48) |
| LR− (<1) | 0.04 (0.02, 0.07) | 0.17 (0.12, 0.24) | 0.02 (0.01, 0.06) | 0.01 (0.01, 0.07) | 0.01 (0.01, 0.08) |
| ROC (AUC; 0.5–1) | 0.84 (0.81, 0.88) | 0.75 (0.71, 0.79) | 0.73 (0.69, 0.77) | 0.67 (0.62, 0.71) | 0.64 (0.60. 0.68) |
Note: A: ≤1.5 METs (any posture).2 B: ≤1.5 METs (lying or sitting postures only).8 A vs B definitions only affect standing texting and sitting computer workstation categorizations. Notably, all AG cut-points categorized both the standing texting and sitting computer workstation activities as sedentary 100% of the time, so the AG results were the same for both sedentary definition conditions.
SWm=SenseWear Mini; AG3=Actigraph GT3X; A=sedentary activity; B=sedentary behavior; VM=vector magnitude cut-point/minute; VA=vertical axis cut-point/minute; PPV=positive predictive value; NPV=negative predictive value; LR+ =positive likelihood ratio; LR−=negative likelihood ratio; ROC=receiver operating characteristics; AUC=area under the curve; METs=metabolic equivalent tasks.