Table 4.
Five measures of engagement over time (months 1-6, 7-12, and 13-24) by weight change category for cell phone and personal coaching intervention arms.
| Engagement measures and time | Weight change categories | P valuea | rb | ||||||||||
| Gained >2% | Gained ≤2% or lost <2% | Lost ≥2% to <5% | Lost ≥5% | ||||||||||
| n | Mean (SD) | n | Mean (SD) | n | Mean (SD) | n | Mean (SD) | ||||||
| Percentage of days apps usedc | |||||||||||||
| 1-6 months | |||||||||||||
| CPd | 31 | 74.4 (17.0) | 41 | 68.5 (21.3) | 20 | 75.4 (23.6) | 22 | 83.4 (15.5) | .04 | −.213 | |||
| PCe | 16 | 40.2 (23.0) | 39 | 42.4 (22.5) | 29 | 52.5 (19.6) | 26 | 59.9 (20.4) | .004 | −.319 | |||
| 7-12 months | |||||||||||||
| CP | 24 | 52.2 (23.6) | 46 | 59.2 (24.3) | 24 | 56.0 (24.9) | 11 | 60.6 (31.5) | .68 | .004 | |||
| PC | 27 | 24.3 (19.9) | 44 | 31.8 (23.8) | 21 | 44.2 (26.4) | 13 | 27.7 (13.1) | .02 | −.124 | |||
| 13-24 months | |||||||||||||
| CP | 30 | 28.7 (24.7) | 43 | 40.9 (25.4) | 13 | 34.2 (21.4) | 10 | 43.3 (20.5) | .15 | −.127 | |||
| PC | 43 | 22.0 (21.2) | 32 | 19.0 (18.8) | 15 | 19.7 (20.7) | 8 | 24.8 (19.6) | .86 | .058 | |||
| Number of app uses per dayc | |||||||||||||
| 1-6 months | |||||||||||||
| CP | 31 | 5.0 (2.5) | 41 | 4.3 (2.5) | 20 | 6.4 (3.8) | 22 | 6.8 (3.5) | .006 | −.264 | |||
| PC | 16 | 1.2 (1.0) | 39 | 1.3 (0.9) | 29 | 1.9 (1.4) | 26 | 2.3 (1.3) | .001 | −.308 | |||
| 7-12 months | |||||||||||||
| CP | 24 | 1.7 (1.5) | 46 | 1.8 (1.1) | 24 | 1.7 (1.3) | 11 | 2.2 (1.8) | .70 | −.035 | |||
| PC | 27 | 0.5 (0.5) | 44 | 0.8 (0.9) | 21 | 1.3 (1.2) | 13 | 0.6 (0.3) | .02 | −.109 | |||
| 13-24 months | |||||||||||||
| CP | 30 | 0.6 (0.6) | 43 | 0.7 (0.6) | 13 | 0.6 (0.4) | 10 | 0.8 (0.4) | .56 | −.053 | |||
| PC | 43 | 0.5 (0.6) | 32 | 0.4 (0.5) | 15 | 0.5 (0.5) | 8 | 0.5 (0.4) | .96 | .042 | |||
| Percentage of days weighed self | |||||||||||||
| 1-6 months | |||||||||||||
| CP | 31 | 52.1 (22.4) | 41 | 51.9 (23.9) | 20 | 60.8 (25.6) | 22 | 70.2 (18.8) | .01 | −.297 | |||
| PC | 16 | 24.2 (19.2) | 39 | 26.3 (22.6) | 29 | 35.4 (21.3) | 26 | 45.4 (24.0) | .003 | −.354 | |||
| 7-12 months | |||||||||||||
| CP | 24 | 40.8 (25.6) | 46 | 50.6 (24.1) | 24 | 48.8 (27.0) | 11 | 52.5 (34.0) | .46 | −.031 | |||
| PC | 27 | 14.2 (18.6) | 44 | 20.3 (20.2) | 21 | 30.7 (26.1) | 13 | 17.6 (12.5) | .05 | −.139 | |||
| 13-24 months | |||||||||||||
| CP | 30 | 24.4 (25.2) | 43 | 36.3 (25.8) | 13 | 28.3 (21.8) | 10 | 36.5 (20.6) | .20 | −.109 | |||
| PC | 43 | 16.4 (19.8) | 32 | 13.0 (16.2) | 15 | 14.3 (17.8) | 8 | 20.3 (15.9) | .73 | .066 | |||
| Percentage of group sessionsf attended | |||||||||||||
| 1-6 months | |||||||||||||
| PC | 16 | 87.5 (22.3) | 39 | 92.3 (17.8) | 29 | 96.5 (8.2) | 26 | 94.8 (14.1) | .29 | −.194 | |||
| Percentage of group sessionsf and monthly calls attended | |||||||||||||
| 1-6 months | |||||||||||||
| PC | 16 | 90.6 (14.0) | 39 | 94.2 (10.2) | 29 | 97.4 (5.6) | 26 | 96.9 (7.8) | .09 | −.246 | |||
| 7-12 months | |||||||||||||
| PC | 27 | 98.7 (4.5) | 44 | 90.9 (21.7) | 21 | 95.2 (16.0) | 13 | 100.0 (0.0) | .13 | −.066 | |||
| 13-24 months | |||||||||||||
| PC | 43 | 89.6 (18.8) | 32 | 89.8 (18.5) | 15 | 92.9 (15.2) | 8 | 88.6 (18.2) | .92 | .019 | |||
aP value for the one-way analysis of variance (ANOVA) test comparing mean engagement measures across weight change categories.
bPearson correlation coefficient for measuring linear association between engagement and percentage change in weight over time (where weight loss is indicated by a percentage change less than zero; a negative correlation indicates a positive association between increased engagement and weight loss).
cIncludes self-weighing.
dCP: cell phone.
ePC: personal coaching.
fGroup sessions only occur in the first 2 months.