Table 2. Mean Changes in Weight-Related Outcomes.
| Combined intervention | Online program only | Usual care | P value | |
|---|---|---|---|---|
| No. of total participants | 298 | 216 | 326 | |
| Primary analysis: changes from baseline to 12 moa | ||||
| Weight, kg | ||||
| At baseline | 92.1 | 91.4 | 92.3 | |
| Change at 12 mo (95% CI) | –3.1 (–3.7 to –2.5) | –1.9 (–2.6 to –1.1) | –1.2 (–2.1 to –0.3) | <.001b |
| Weight change at 12 mo, % (95% CI) | –3.0 (–3.8 to –2.1) | –1.9 (–2.8 to –1.0) | –1.4 (–2.3 to –0.6) | <.001b |
| Participants had ≥5% weight loss at 12 mo, % (95% CI) | 32.3 (25.8 to 38.8) | 20.8 (14.5 to 27.2) | 14.9 (10.2 to 19.6) | <.001b |
| Confidence in ability to lose weight, pointsc | ||||
| At baseline | 6.5 | 6.8 | 6.8 | |
| Change at 12 mo (95% CI) | 0.5 (0.06 to 0.9) | –0.4 (–0.9 to 0.07) | –0.7 (–1.1 to–0.3) | <.001b |
| Secondary analysis: changes over entire 18-mo follow-up periodd | ||||
| Weight, kg | ||||
| At baseline | 92.1 | 91.4 | 92.3 | <.001e |
| Change at 6 mo (95% CI) | –2.9 (–3.5 to –2.3) | –2.1 (–2.8 to –1.5) | –1.0 (–1.9 to –0.1) | |
| Change at 12 mo (95% CI) | –3.1 (–3.7 to –2.5) | –1.9 (–2.6 to –1.1) | –1.2 (–2.1 to –0.3) | |
| Change at 18 mo (95% CI) | –2.8 (–3.5 to –2.0) | –1.1 (–2.0 to –0.3) | –1.9 (–2.8 to –1.0) | |
| Weight change, % (95% CI) | ||||
| At 6 mo | –2.8 (–3.8 to –1.8) | –2.0 (–3.1 to –0.9) | –1.0 (–1.9 to 0.03) | .01e |
| At 12 mo | –2.9 (–3.9 to –2.0) | –1.7 (–2.8 to –0.6) | –1.2 (–2.1 to –0.2) | |
| At 18 mo | –2.6 (–3.6 to –1.5) | –0.9 (–2.0 to 0.2) | –1.9 (–2.9 to –0.9) | |
| Participants lost ≥5% of body weight, % (95% CI) | ||||
| At 6 mo | 29.5 (21.4 to 37.5) | 22.1 (14.2 to 30.0) | 13.4 (7.8 to 19.0) | .20e |
| At 12 mo | 31.5 (23.4 to 39.5) | 20.4 (13.0 to 27.9) | 12.7 (7.7 to 17.7) | |
| At 18 mo | 31.3 (23.0 to 39.6) | 19.9 (12.5 to 27.3) | 20.9 (14.3 to 27.6) | |
| Aggregate estimate across all 3 time points | 30.7 (22.4 to 39.0) | 20.8 (13.0 to 28.6) | 15.7 (6.2 to 25.1) | <.001e |
Used repeated-measures models including baseline and 12-month time points adjusting for age, sex, race/ethnicity, educational level, and medical conditions (type 2 diabetes, hypertension, and hyperlipidemia). Clinic type (community-based clinic, hospital-based, or community health center) was included as a fixed effect. Clinic, physician, and patient were included as random effects. Fully conditional specification multiple imputation with 25 imputations was used to estimate missing weights and other outcomes and covariates and was based on available data for 91 patient variables.
From global F tests examining the statistical significance of the study group × 12-month time point interaction term.
Assessed on the baseline and follow-up patient surveys using a 10-point Likert scale where 1 indicates “not at all confident” and 10 indicates “very confident.”23
Used repeated-measures models including all time points adjusting for age, sex, race/ethnicity, educational level, and medical conditions (type 2 diabetes, hypertension, and hyperlipidemia). Clinic type (community-based clinic, hospital-based, or community health center) was included as a fixed effect. Clinic, physician, and patient were included as random effects. Fully conditional specification multiple imputation with 25 imputations was used to estimate missing weights and other outcomes and covariates and was based on available data for 91 patient variables. Models also included time × study group interaction terms and no assumption was made that the treatment effects were consistent across time.
From the time × study group interactions. Significant P values indicate that the effects of the interventions diverge from each other over time. For the percentage of patients who lost at least 5% of their body weight, the model showed no significant time × study group interaction (ie, the differences among groups were consistent over time). Another model was run without the interaction terms and the aggregate effect across time reflects the overall differences among the study groups.