NPA-GP: Impact of Intervention Components (2021)
Impact of Intervention Components Examined in Sub-Group Analyses
A priori, the expert panel identified several sub-questions of interest with the aim of identifying successful intervention components to guide practice. In all analyses, intervention groups are compared to control groups statistically, and effect sizes between intervention types are compared qualitatively. Sub-group analyses examined the impact of:
- Practitioner
- In-person vs remote delivery
- Individual vs group contacts
- Number of contacts
- Study duration
- Level of nutrition and physical activity interventions
Sub-group analyses were possible for five outcomes, including physical activity amount, fruit intake (as a proxy for fruit and vegetable intake), waist circumference, achieving 5% weight loss for adults with overweight or obesity and glucose levels. Results of sub-group analyses are described in the table below. There were few clear patterns in results according to intervention components. Lack of statistical significance often seemed to be a product of little research available for a certain sub-group, which likely increased confidence intervals. Even when there was a greater effect size for some intervention component compared to another, confidence intervals overlapped, and thus any conclusions should be made with caution. However, there were some patterns of note:
- Interventions provided by both a dietitian and a qualified exercise practitioner were the only intervention types to significantly improve glucose levels in participants.
- There were few studies available examining the efficacy of a health coach. Available studies did not demonstrate a significant effect of interventions provided by a health coach compared to controls for most outcomes.
- Providing exclusively individual contacts or a hybrid of individual and group contacts resulted in significant improvement in outcomes of interest, while interventions that were exclusively remote did not result in significantly improved outcomes.
- While there were no clear dose-response patterns, even providing interventions with less than 5 contacts with practitioner(s) resulted in significant improvement in physical activity, fruit intake and glucose levels.
Table1. Sub-group Analyses Results from Nutrition and Physical Activity for the General Population
*Cells highlighted in green indicate a statistically significant improvement.
| Waist Circumference (cm) | Achieving 5% Weight Loss (for participants with overweight or obesity) |
Physical Activity Amount |
Fruit Intake |
Glucose Levels (12 RCTs) |
|
|---|---|---|---|---|---|
| Measure | FGMD (95% CI) | RR (95% CI) | SMD (95% CI) | SMD (95% CI) | SMD (95% CI) |
| Practitioner | |||||
| Dietitian & Exercise Practitioner | -2.49 (-4.03, -0.95) 8 RCTs |
2.07 (1.47, 2.91) 3 RCTs |
.0.56 |
0.43 (-0.11, 0.98) 2 RCTs |
-0.26 (-0.42, -0.11) 8 RCTs |
| Dietitian | -2.61 (-3.79, -1.44) 5 RCTs |
5.75 (1.11, 29.77) 2 RCTs |
0.18 (0.07, 0.28) 4 RCTs |
0.47 (-0.01, 0.96) 5 RCTs |
-0.17 (-0.79, 0.46) 2 RCTs |
| Health Coach | -1.19 (-2.42, 0.03) 4 RCTs |
2.34 |
0.15 (-0.04, 0.35) 4 RCTs |
0.20 (0.02, 0.38) 2 RCTs |
-0.13 (-0.61, 0.35) 1 RCT |
| Unclear/Other | -2.20 (-7.44, 3.04) 1 RCT |
0 RCTs | -0.02 (-0.36, 0.31) 1 RCT |
0 RCTs | -0.45 (-1.15, 0.25) 1 RCT |
| Remote vs. In-Person | |||||
| Exclusively In-Person | -3.00 (-4.04, -1.96) 9 RCTs |
2.99 (0.74, 12.14) 4 RCTs |
0.20 (0.05, 0.34) 4 RCTs |
0.66 (-0.04, 1.36) 4 RCTs |
-0.28 (-0.44, -0.12) 8 RCTs |
| Exclusively Remote | -1.05 (-1.21, -0.88) 4 RCTs |
1.98 (0.75, 5.22) 2 RCTs |
0.20 (0.10, 0.30) 5 RCTs |
0.22 (-0.06, 0.50) 3 RCTs |
0.01 |
| Hybrid In-Person / Remote |
-3.23 (-5.32, -1.13) 5 RCTs |
2.34 (1.43, 3.84) 2 RCTs |
0.32 (-0.25, 0.89) 4 RCTs |
0.16 (-0.08, 0.39) 2 RCTs |
-0.29 (-0.52, -0.06) 2 RCTs |
| Group vs. Individual | |||||
| Exclusively Individual | -1.48 (-2.14, -0.82) 10 RCTs |
2.11 (1.38, 3.21) 4 RCTs |
0.14 |
0.24 (0.06, 0.42) 7 RCTs |
-0.11 (-0.33, 0.11) 6 RCTs |
| Exclusively Group | -0.24 (-4.66, 4.19) 2 RCTs |
10.08 (0.58, 175.41) 1 RCT |
0 RCTs | 0.87 (-0.64, 2.38) 2 RCTs |
-0.13 (-0.61, 0.35) 1 RCT |
| Hybrid Individual / Group |
-3.66 (-4.95, -2.37) 6 RCTs |
5.00 (0.67, 37.22) 2 RCTs |
0.39 (-0.05, 0.84) 5 RCTs |
0 RCTs | -0.34 (-0.51, -0.16) 5 RCTs |
| Number of Contacts | |||||
| <5 Contacts | -0.95 (-2.01, 0.12) 3 RCTs |
0 RCTs | 0.23 (0.02, 0.44) 2 RCTs |
0.20 (0.93, 0.37) 3 RCTs |
-0.47 (-0.90, -0.04) 1 RCT |
| 5-10 Contacts | -1.05 (-1.21, -0.88) 4 RCTs |
3.61 (0.61, 21.51) 2 RCTs |
0.13 (-0.09, 0.34) 3 RCTs |
0.48 (0.25, 0.71) 2 RCTs |
-0.10 (-0.39, 0.19) 4 RCTs |
| >10 Contacts | -3.20 (-4.14, -2.26) 10 RCTs |
2.29 (1.56, 3.35) 5 RCTs |
0.31 (-0.06, 0.68) 6 RCTs |
0.69 (-0.34, 1.72) 3 RCTs |
-0.21 (-0.41, -0.01) 7 RCTs |
| Unclear | 0 RCTs | 0 RCTs | 0.20 (0.08, 0.32) 2 RCTS |
0.0 (-0.13, 0.13) 1 RCT |
0 RCTs |
| Study Duration | |||||
| <6 months | -2.47 (-3.84, -1.10) 6 RCTs |
2.92 (1.16, 7.33) 4 RCTs |
0.30 (-0.19, 0.77) 1 RCT |
0.71 (-0.28, 1.69) 3 RCTs |
-0.36 (-0.60, -0.11) 4 RCTs |
| 6-<12 months | -1.05 (-1.22, -0.88) 5 RCTs |
1.87 (0.19, 18.38) 1 RCT |
0.19 (0.10, 0.28) 6 RCTs |
0.19 (-0.01, 0.39) 4 RCTs |
-0.05 (-0.01, 0.31) 3 RCTs |
| 12 months or greater | -2.68 (-4.15, -1.21) 7 RCTs |
2.08 (1.62, 2.66) 2 RCTs |
0.31 (-0.07, 0.69) 6 RCTs |
0.43 (-0.19, 1.05) 2 RCTs |
-0.18 (-0.41, 0.05) 5 RCTs |
| Level of Nutrition Intervention | |||||
| Nutrition Education | -1.06 (-1.23, -0.89) 6 RCTs |
3.80 (1.14, 12.65) 4 RCTs |
0.19 (0.01, 0.37) 6 RCTs |
0.93 (-0.41, 2.27) 2 RCTs |
-0.22 (-0.58, 0.13) 3 RCTs |
| Nutrition Counseling | -2.78 (-3.95, -1.62) 11 RCTs |
2.27 (1.50, 3.43) 3 RCTs |
0.29 (0.02, 0.56) 7 RCTs |
0.22 (0.03, 0.42) 7 RCTs |
-0.30 (-0.44, -0.17) 8 RCTs |
| Other / Unclear | -1.30 (-3.24, 0.64) 1 RCT |
0 RCTs | 0 RcTs | 0 RCTs | 0.12 (-0.36, -0.07) 1 RCT |
| Level of PA Intervention | |||||
| PA Education | -1.47 (-2.06, -0.88) 11 RCTs |
2.44 (1.41, 4.21) 6 RCTs |
0.16 (0.07, 0.25) 10 RCTs |
0.39 (0.11, 0.66) 8 RCTs |
-0.27 (-0.48, -0.07) 7 RCTs |
| PA Coaching | -4.22 (-5.83, -2.61) 6 RCTs |
2.20 (1.62, 3.00) 1 RCT |
0.46 (-0.28, 1.20) 3 RCTs |
0.29 (-0.47, 1.05) 1 RCT |
-0.28 (-0.47, -0.08) 4 RCTS |
| Other / Unclear |
-1.30 |
0 RCTs | 0 RCTs | 0 RCTs | 0.12 (-0.17, 0.41) 1 RCT |
CI=confidence interval; MD=mean difference; PA=physical activity; RCT=randomized controlled trial; RR=relative risk; SMD=standardized mean difference
Postpartum Adults
A priori, panel members specified that results should be examined for studies targeting adults who were postpartum, since this represents a time of rapid biological changes. Effect sizes were similar between adults who were postpartum and those who were not.
Table 2: Effect of Nutrition and Physical Activity Interventions Provided by Qualified Practitioners on Adults who are Healthy or have Cardiometabolic Risk according to Postpartum Status
| Outcome | Units / Measures | Postpartum | Not Postpartum |
|---|---|---|---|
| Physical Activity Amount | SMD (95% CI) |
0.15 |
0.27 (0.06, 0.48) 10 RCTs |
| Fruit Intake | SMD (95% CI) | 0.29 (-0.47, 1.05) 1 RCT |
0,39 (0.11, 0.66) 8 RCTs |
| Waist Circumference | Cm;: MD (95% CI) | -2.77 (-4.51, -1.03) 4 RCTs |
-1.76 (-2.63, -0.89) 14 RCTs |
| 5% Weight Loss (with overweight or obesity at baseline) | RR (95% CI) | 2.39 (1.84, 3.12) 3 RCTs |
2.40 (0.97, 5.96) 5 RCTs |
| Glucose Levels | SMD (95% CI) | -0.26 (-0.79, 0.28) 2 RCTs |
-0.17 (-0.32, -0.02) 10 RCTs |
| HbA1c (for those with diabetes risk) | %, MD (95% CI) | -0.05 (-0.19, 0.09) 1 RCT |
0.12 (-0.12, 0.36) 2 RCTs |
| Anxiety/Depression | NA | 0 RCTs | 0 RCTs |
| Quality of Life | NA | Not significant 1 RCT |
Not significant 6 RCTs |
Cm=centimers; CI=confidence interval; MD=mean difference; PA=physical activity; RCT=randomized controlled trial; RR=relative risk; SMD=standardized mean difference