# Abstract

 

## Background Extending contact with participants after initial, intensive intervention may support maintenance of weight loss and related behaviors. 

## Objective This community-wide trial evaluated a text message (short message service, SMS)-delivered, extended contact intervention ('Get Healthy, Stay Healthy' (GHSH)), which followed on from a population-level, behavioral telephone coaching program. 

## Methods This study employed a parallel, randomized controlled trial: GHSH compared with no continued contact (standard practice). Participants (n=228) were recruited after completing a 6-month lifestyle telephone coaching program: mean age = 53.4 (standard deviation (SD)=12.3) years; 66.7% (152/228) female; mean body mass index (BMI) upon entering GHSH=29.5 kg/m2 (SD = 6.0). Participants received tailored text messages over a 6-month period. The message frequency, timing, and content of the messages was based on participant preference, ascertained during two tailoring telephone calls. Primary outcomes of body weight, waist circumference, physical activity (walking, moderate, and vigorous sessions/week), and dietary behaviors (fruit and vegetable serves/day, cups of sweetened drinks per day, takeaway meals per week; fat, fiber and total indices from the Fat and Fiber Behavior Questionnaire) were assessed via self-report before (baseline) and after (6-months) extended contact (with moderate-vigorous physical activity (MVPA) also assessed via accelerometry). 

## Results Significant intervention effects, all favoring the intervention group, were observed at 6-months for change in weight (-1.35 kg, 95% confidence interval (CI): -2.24, -0.46, *P*=.003), weekly moderate physical activity sessions (0.56 sessions/week, 95% CI: 0.15, 0.96, *P*=.008) and accelerometer-assessed MVPA (24.16 minutes/week, 95% CI: 5.07, 43.25, *P*=.007). Waist circumference, other physical activity outcomes and dietary outcomes, did not differ significantly between groups. 

## Conclusions The GHSH extended care intervention led to significantly better anthropometric and physical activity outcomes than standard practice (no contact). This evidence is useful for scaling up the delivery of GHSH as standard practice following the population-level telephone coaching program. # Results 

## Participants There were 1071 clients invited to participate in this study, of whom 300 expressed verbal interest in participating in the trial, and 228 participants consented and were randomized (228/300, 76%; [Figure 1](#)). [Table 1](#) shows the demographic characteristics of GHSH participants (intervention, n=114; control, n=114). Upon entering the GHSH trial, participants (152/228, 67% female) had a mean age of 53.4 (standard deviation (SD) = 12.3) years and BMI of 29.5 kg/m^2^(SD = 6.0), 34% (78/228) were overweight and 38% (87/228) were obese, 40% (91/228) did not meet physical activity guidelines \[[28](#)\] (ie, \<150 minutes MVPA per week), and 80% (182/228) did not consume the recommended serves of fruit (ie, two) and/or vegetables (ie, five) per day \[[29](#)\].The GHSH sample was not representative of all participants completing the final GHS coaching call. Odds of being in the GHSH trial were significantly higher than their respective counterparts for those: aged \<60 years; not working; without a post school qualification; self-reported diagnosis of hypertension; self-reported diagnosis of high cholesterol; doing no vigorous activity; and, who consume \<1 takeaway meal per week ([Multimedia Appendix 2](#)). The overall retention rate from baseline to 6 months was 95% (216/228) (103/114, 90% in intervention and 113/114, 99% in controls, *P*=.005). Most intervention participants (98/114, 86%) and controls (107/114, 94%) had full data on all outcomes at 6-month follow-up and on the baseline and prestudy covariates examined ( *P*=.077). Missing data was associated with: higher baseline BMI (mean ± SD for missing vs complete; <figure> <p><img src="" /></p> <figcaption>Participation in the Get Healthy, Stay Healthy (GHSH) trial.</figcaption> </figure> ::::table-wrap

::: caption
Characteristics of 'Get Healthy, Stay Healthy' (GHSH) trial
participants.
:::

______________________________________________________________________

```
                                   Mean (SD) or n (%)                                                             
```

______________________________________________________________________

```
                                   GHSH (n=114)^a^                                           Control (n=114)^a^   
```

Health and demographics at baseline

```
                                      Age (years)                                            55.5 (12.3)          51.2 (11.9)

                                      BMI (kg/m^2^)                                          29.3 (5.8)           29.6 (6.3)

                                      Weight (kg)                                            82.8 (19.4)          83.6 (18.9)

                                      Waist circumference (cm)                               98.9 (15.4)          99.6 (14.9)

                                      Gender (% female)                                      74 (64.9%)           78 (68.4%)

                                      In paid employment (% yes)                             69 (61.1%)           68 (59.6%)

                                      Education (% post-school qualification)                73 (64.0%)           77 (67.5%)

                                      Indigenous Australian (%)                              1 (0.9%)             5 (4.4%)

                                      SEIFA^b^(% living in most advantaged 3 quintiles)^c^   86 (75.4%)           78 (68.4%)

                                      Region (% living in major cities)                      71 (62.3%)           82 (71.9%)
```

Physical activity at baseline

```
                                      Accelerometer PA^d^(minutes/week)                      196.9 (144.4)        196.2 (143.6)

                                      Vigorous PA (sessions/week)                            1.56 (1.86)          2.33 (2.53)

                                      Moderate PA (sessions/week)                            1.11 (1.78)          1.60 (1.97)

                                      Walking PA (sessions/week)                             3.99 (3.04)          3.30 (2.44)
```

Dietary behaviors at baseline

```
                                      Vegetables (servings/day)                              3.1 (1.4)            3.4 (1.8)

                                      Fruit (servings/day)                                   2.0 (0.9)            2.0 (1.0)

                                      Sweetened drinks (cups/day)                            0.2 (0.5)            0.4 (0.9)

                                      Takeaway (meals/week)                                  0.5 (0.8)            0.5 (0.9)

                                      FFBQ Total Index (Score (1-5)                          3.3 (0.4)            3.3 (0.4)

                                      FFBQ Fat Index (Score (1-5)                            3.5 (0.5)            3.5 (0.5)

                                      FFBQ Fiber Index (Score (1-5)                          2.9 (0.5)            2.9 (0.5)
```

Prior changes during GHS

```
                                      Weight (kg)                                            −3.7 (4.0)^e^        −3.8 (4.3)^e^

                                      Waist circumference (cm)                               −5.5 (5.0)^e^        −6.3 (5.7)^e^

                                      Vigorous PA (sessions/week)                            0.5 (1.4)^e^         0.6 (1.7)^e^

                                      Moderate PA (sessions/week)                            0.5 (2.1)^e^         0.9 (2.2)^e^

                                      Walking PA (sessions/week)                             1.7 (2.7)^e^         1.1 (2.6)^e^

                                      Vegetables (servings/day)                              1.2 (1.5)^e^         1.2 (1.4)^e^

                                      Fruit (servings/day)                                   0.6 (1.2)^e^         0.7 (1.1)^e^

                                      Sweetened drinks (cups/day)                            −0.2 (0.6)^e^        −0.3 (1.2)^e^

                                      Takeaway (meals/week)                                  −0.5 (1.6)^e^        −0.5 (1.5)^e^
```

______________________________________________________________________

^a^Figures exclude missing data: one GHSH intervention participant
(employment, English spoken at home, referral source, accelerometer PA)
and one control participant (waist circumference, Indigenous status).

^b^Socioeconomic Indexes for Areas.

^c^Specifically the Index of Relative Socio-Economic Advantage and
Disadvantage.

^d^Physical activity.

^e^Statistically significant change during GHS ( *P*\<.05) based on
*t*-test.:::: 32.7 ± 7.3 vs 29.1 ± 5.8 kg/m^2^, *P*=.006); higher baseline weight (90.8 ± 19.5 vs 82.3 ± 18.9 kg, *P*=.044); higher rates of Type 2 Diabetes at baseline (8/23, 34.8% vs 22/205, 10.7%, *P*=.004); higher rates of smoking at baseline (5/23, 21.7% vs 7/205, 3.4%, *P*=.003); and lower vegetable intake at baseline (2.5 ± 1.1 vs 3.4 ± 1.6 servings per day, *P*=.012) ([Multimedia Appendix 3](#)). Participant's reasons for discontinuing the intervention are shown in [Figure 1](#), with the most common reasons being that they were too busy (4/13) or that the intervention was not working for them (4/13). 

## Anthropometric and Behavior Change Results 

### Anthropometric Outcomes Intervention participants showed significant reductions in both body weight (−0.89 kg, 95% CI: −1.53, −0.25) and waist circumference (−1.34 cm, 95% CI: −2.31, −0.36; [Table 2](#)). Intervention group improvements were significantly greater than controls for weight loss (−1.35 kg, 95% CI: −2.24, −0.46, *P*=.003), but not for waist circumference ( *P*=.115; [Table 3](#)). 

### Physical Activity The intervention group maintained their accelerometer-assessed MVPA and self-reported vigorous activity, and changed significantly only in self-reported walking (−0.55, 95% CI: −0.99, −0.11 sessions/week; [Table 2](#)). The control group changed significantly in moderate activity and MVPA, which both declined (−0.68, 95% CI: −1.11, -0.26 sessions/week, and −16.10, 95% CI −28.60, −3.61 min/week; [Table 2](#)). The intervention group did significantly better than the control group in moderate activity (0.56, 95% CI: 0.15, 0.96 sessions/week) and in accelerometer-assessed MVPA (24.16, 95% CI: 5.07, 43.25 min/week; [Table 3](#)). Intervention effects for walking and vigorous activity were not significant ([Table 3](#)). 

### Dietary Behaviors In the intervention group, small, but statistically significant improvements in dietary outcomes were observed for the FFBQ Fiber and Total Indices, while remaining dietary outcomes, except takeaway meals per week, were all maintained ([Table 2](#)). By contrast, in the control group, there were no statistically significant improvements, only statistically significant declines in vegetable intake and fruit intake ([Table 2](#)). Other dietary outcomes were maintained. No significant or meaningful intervention effect for dietary outcomes was observed. 

### Sensitivity Analyses Results from analyses using multiple imputation mostly supported the interpretations from the main analyses ([Multimedia Appendix 4](#)), except that due to slightly narrower CIs in the multiple imputation analysis, the intervention group maintained takeaway meals/week (rather than being 'inconclusive') and the intervention effect for vegetable serves/day was 'similar' (rather than 'inconclusive'). Conclusions using the alternative models mostly supported the main findings ([Multimedia Appendix 5](#)) and revealed significant differences in walking ( *P*=.018). The intervention group showed a greater tendency to walk than controls (odds ratio = 2.17, 95% CI: 0.45, 10.43, *P*=.334), but also to report fewer walking sessions when they did walk than controls (relative rate = 0.77, 95% CI: 0.64, 0.92, *P*=.005). 

## Feasibility Results The mean (±SD) call duration was 34 ±8 minutes for the initial tailoring call and 18 ±8 minutes for the 12-week tailoring call. The median number of text messages requested during the initial tailoring call and at the 12-week tailoring call were both five per fortnight (25^th^-75^th^percentiles =3-7 texts). During the initial tailoring call, 40% (46/111) of participants requested fortnightly goal checks for both behavioral goals; 35% (40/111) weekly for both goals; and, 22%(25/111) weekly for one goal and fortnightly for the other goal. Approximately one-half the participants (58/111, 52%) did not request any real-time behavioral prompts and 35% (39/111) requested between 2-4 prompts per fortnight. Almost all (89/95, 94%) intervention participants still enrolled at 12-weeks completed the 12-week tailoring interview. During the 12-week tailoring call, almost all (82/89, 92%) participants changed their preference for text message content, and 40% (36/89) changed their preferred text message schedule. Outside of the 12-week tailoring call, only 3% (3/90) of participants changed either of these preferences via text. The weight goal reset text received replies from 30% (33/111) of participants at week 6 and 26% (25/95) at week 18. At week 6, 40% (44/111) of participants reset at least one behavioral goal; 29% (28/95) did so in week 18. Intervention completers (n=90) replied to 84% of goal check texts sent in week 1 (152/180) and 69% (125/180) of goal check texts sent in the last week. 

## Acceptability Results Most (69/99, 70%) participants rated GHSH as "useful" or "extremely useful" in supporting their weight goal, and 75% (74/99) reported that they were "satisfied" or "extremely satisfied" with the intervention. Follow-up interviews with 62 intervention participants revealed that: experience with text messaging prior to GHSH impacted on participants' experience during the intervention; the GHSH program often exceeded participants' expectations; and participants generally perceived the GHS and GHSH intervention to be one program. Reasons for liking GHSH focused on: the reminders provided by the text messages to reinforce what participants wanted to do; maintaining accountability; and increased awareness of behaviors in real time. The few participants who did not like aspects of the GHSH nominated text messages being too repetitive or automated as key reasons. 

## Costs of Intervention Delivery Results Health coach staff spent, on average, 35 minutes per participant conducting and preparing for the initial tailoring interview and 30 minutes for the 12-week tailoring interview. Research staff spent on average 31 minutes per participant entering tailoring data into the software following the initial tailoring call and 15 minutes per participant after the 12-week tailoring call. Research staff had to manually trigger responses to 813 goal check replies not recognized by the software (813/2071, 39%) of responses received), which took approximately 1 minute per response. During the intervention, 8518 text messages were sent to participants (at AU$0.15 each) totaling AU$1278 (averaging AU$11.21 per participant). Overall, it cost approximately AU$80.00 per participant to deliver the GHSH extended contact intervention. ::::table-wrap
::: caption
Mean changes within the 'Get Healthy, Stay Healthy' (GHSH) intervention
group (I; n=104) and the control group (C; n=114)
:::

______________________________________________________________________

```
                                                         MDI           Group   Mean Change                 Within−group    
                                                                                 (6 months -- baseline)^a^    interpretation   
```

______________________________________________________________________

```
                                                                             Mean (95% CI)                *P*              
```

Anthropometry

```
                      Weight (kg)                         1 kg          I       − *0.89 (−1.53, −0.25)*^b^   *.007*           Improved

                                                                      C       0.30 (−0.35, 0.95)           .357             Maintained

                      Waist circumference^c^(cm)          1 cm          I       − *1.34 (−2.31, −0.36)*      *.008*           Improved

                                                                      C       −0.32 (−1.47, 0.82)          .578             Inconclusive
```

Physical activity (PA)

```
                      Vigorous PA (sessions/week)         0.5 session   I       0.20 (−0.10, 0.50)           .183             Maintained

                                                                      C       −0.40 (−0.86, 0.05)          .084             Inconclusive

                      Moderate PA (sessions/week)         0.5 session   I       0.19 (−0.16, 0.54)           .277             Inconclusive

                                                                      C       − *0.68 (−1.11, −0.26)*      *.002*           Worsened

                      Walking PA (sessions/week)          0.5 session   I       − *0.55 (−0.99, −0.11)*      *.015*           Worsened

                                                                      C       0.31 (−0.40, 1.01)           .392             Inconclusive

                      Accelerometer PA^d^(minutes/week)   30 minutes    I       7.41 (−5.61, 20.44)          .265             Maintained

                                                                      C       − *16.10 (−28.60, −3.61)*    *.012*           Worsened
```

Dietary behaviors

```
                      Vegetables (servings/day)           0.5 serves    I       −0.17 (−0.46, 0.12)          .237             Maintained

                                                                      C       − *0.41 (−0.71, −0.12)*      *.006*           Worsened

                      Fruit (servings/day)                0.5 serves    I       −0.06 (−0.22, 0.10)          .482             Maintained

                                                                      C       − *0.22 (−0.39,−0.05)*       *.011*           Worsened

                      Sweetened drinks (cups/ day)        0.25 cups     I       −0.00 (−0.08, 0.08)          .982             Maintained

                                                                      C       −0.04 (−0.19, 0.11)          .602             Maintained

                      Takeaway (meals/week)               0.25 meal     I       −0.13 (−0.28, 0.02)          .379             Inconclusive

                                                                      C       −0.06 (−0.19, 0.07)          .079             Maintained

                      FFBQ Total Index Score (1--5)       0.2 units     I       *0.07 (0.02, 0.12)*          *.011*           Improved

                                                                      C       0.01 (−0.05, 0.07)           .781             Maintained

                      FFBQ Fat Index Score (1--5)         0.2 units     I       0.06 (−0.01, 0.13)           .082             Maintained

                                                                      C       0.03 (−0.04, 0.11)           .368             Maintained

                      FFBQ Fiber IndexScore (1--5)        0.2 units     I       *0.08 (0.01, 0.16)*          *.028*           Improved

                                                                      C       −0.03 (−0.12, 0.06)          .493             Maintained
```

______________________________________________________________________

^a^Mean changes estimated by paired *t*-test within completers, or by
marginal means from GEE models for daily accelerometer MVPA (which was
back-transformed from the log scale and multiplied by 7 yield
minutes/week).

^b^Italic values indicate statistical significance at P˂.05.

^c^n=103 GHSH group; n=112 control group (item missing data for waist
circumference).

^d^n=99 GHSH group; n=108 control group; some participants did not wear
the accelerometer.:::: ::::table-wrap
::: caption
Mean differences in changes between the 'Get Healthy, Stay Healthy'
(GHSH) intervention (I; n=104) and control groups (C; n=114).
:::

______________________________________________________________________

```
                      Mean difference                  Between-group interpretation            
                       (GHSH -- control)^a^                                                      
```

______________________________________________________________________

```
                      Mean (95% CI)                     *P*                                    
```

Anthropometry

```
                      Weight (kg)                       − *1.35 (−2.25, −0.46)*^b^     *.003*   significantly better

                      Waist circumference^c^(cm)        −1.18 (−2.65, 0.29)            .116     inconclusive
```

Physical activity (PA)

```
                      Vigorous PA (sessions/week)^d^    0.15 (−0.34, 0.63)             .547     inconclusive

                      Moderate PA (sessions/week)^d^    *0.55 (0.14, 0.96)*            *.008*   significantly better

                      Walking PA (sessions/week)        −0.69 (−1.46, 0.08)            .077     inconclusive

                      Accelerometer PA (mins/week)^e^   *24.16 (5.07, 43.25)*          *.007*   significantly better
```

Dietary behaviors

```
                      Vegetables (servings/day)         0.15 (−0.21, 0.50)             .408     inconclusive

                      Fruit (servings/day)^d^           0.16 (−0.05, 0.37)             .133     similar

                      Sweetened drinks (cups/day)       −0.05 (−0.19, 0.10)            .537     similar

                      Takeaways (meals/week)            0.01 (−0.15, 0.18)             .864     similar

                      FFBQ Total Index Score (1--5)     0.05 (−0.03,0.13)              .195     similar

                      FFBQ Fat Index Score (1--5)       0.02 (−0.07, 0.12)             .615     similar

                      FFBQ Fiber Index Score (1--5)     0.08 (−0.03, 0.19)             .147     similar
```

______________________________________________________________________

^a^Mean difference (β) with 95% CI, and *P*value from linear regression
models, adjusted for baseline values of the outcome and confounders
(listed in [Multimedia Appendix 1](#)).

^b^Italic values indicate statistical significance at P˂.05.

^c^n=102 GHSH group; n=112 control group (item missing data for waist
circumference).

^d^n=103 GHSH group; n=114 control group (item missing data for vigorous
PA, moderate PA and Fruit).

^e^Estimated using marginal means from GEE models of log-transformed
daily MVPA (repeated term for "day"), adjusting for confounders, and
correcting for regression to the mean using the method \[[37](#)\] of
including the term for assessment (pre/post) and the assessment x group
interaction, but not the conditional term for group. Estimates were
back-transformed to the original scale, then multiplied by 7 to yield
minutes per week. n=112 GHSH group; n=114 control group (all
participants with data at either time point examined).::::


Extracted trial result:
Outcome: waist circumference (continuous)
Intervention: Get Healthy, Stay Healthy' (GHSH)
Comparator: no continued contact
Intervention group size: 104
Intervention mean: -0.89
Intervention standard deviation: 3.32
Comparator group size: 114
Comparator mean: 0.3
Comparator standard deviation: 3.54
Notes: Back calculated SD using CI.