Does intervention sequence impact self-regulatory and behavioral outcomes in an adaptive trial among adults with prediabetes?

Figures & data

Table 1. Research Design.

Weeks 1-4: Initial Treatment	Weeks 5-16: Lose > 2.5% weight at week 5?	Months 5-12: Randomization by Matched Pair	Months 12–18 No contact	Intervention Sequence
GLB core (all participants)	Yes: remain in GLB at week 5	GLB or GLB+	Maintain behavioral strategies	GLB/GLB GLB/GLB+
	No: switch to GLB+ at week 5	GLB or GLB+		GLB+/GLB GLB+/GLB+

Data collection occurred at baseline, 4-months following the weekly, intensive intervention phase, 12-months following the extended intervention phase, and 18-months at study end.

Table 2. Components of the intervention description and replication (TIDieR) checklist for each intervention (Hoffmann et al., 2014).

TIDieR Component	Group Lifestyle Balance Intervention	Group Lifestyle Balance Plus Intervention
Why	Focused on self-regulation to promote ≥ 150 minutes/week of physical activity and < 25% of energy intake from fat to promote weight loss	Focused on self-regulatory models of behavioral change consistent with Goal Setting Theory & Hope Theory to promote ≥ 150 minutes/week of physical activity and < 25% of energy intake from fat to promote weight loss
What	Participants received a workbook with key content for each session & activities to complete	Participants received a workbook with key content for each session & activities to complete
What	Weekly weights obtained; identified common obstacles to weight management; self-set goals established; review of goals completed at session beginning; self-monitored weight, dietary intake, & physical activity with feedback from the health coach	Weekly weights obtained; individual action plans established each session; review of action plans completed at session beginning; problem-solving, action planning, & coping planning occurred to identify relevant/likely pathways to achieve goals & overcome personal obstacles to change; emphasized positive agency for change & mindful decision making consistent with core values; self-monitored weight, dietary intake, & physical activity with feedback from the health coach; recognized goal progress
Who provided	Intervention sessions delivered by health coaches with training in nutrition or health behavior	Intervention sessions delivered by health coaches with training in nutrition or clinical psychology
How	In person, group-based sessions delivered prior to the SARS-CoV-2 pandemic; group-based video conferencing sessions employed following pandemic onset	In person, group-based sessions delivered prior to the SARS-CoV-2 pandemic; group-based video conferencing sessions employed following pandemic onset
Where	Implemented at a university worksite in the midwestern US	Implemented at a university worksite in the midwestern US
When & How much	60-minute sessions delivered weekly for 16 weeks; bimonthly for 1 month; monthly for 7 months	60-minute sessions delivered weekly for 16 weeks; bimonthly for 1 month; monthly for 7 months; 3 bimonthly telephone coaching calls occurred during months 6–12
Tailoring	Participants who achieved > 2.5% weight loss at week 5 remained in this intervention at week 5	Participants who did not achieve > 2.5% weight loss at week 5 were stratified to this intervention at week 5
Modifications	Sessions transitioned to videoconferencing sessions at pandemic onset	Sessions transitioned to videoconferencing sessions at pandemic onset
How well	At least 20% of sessions were audio recorded to assess fidelity by the Principal Investigator using a predefined checklist; additional training provided for health coaches as needed (0.13% of sessions included departures from the intervention as planned)	At least 20% of sessions were audio recorded to assess fidelity by the Principal Investigator using a predefined checklist; additional training provided for health coaches as needed (0.20% of sessions included departures from the intervention as planned)

Table 3. Participant characteristics at baseline across four intervention sequences^a.

Characteristic	GLB/GLB (n = 48)	GLB+/GLB+ (n = 63)	P-value	GLB/GLB+ (n = 31)	GLB+/GLB (n = 45)	P-value
	Mean (±SD)			Mean (±SD)
Age (years)	52.15 (±10.19)	48.79 (±10.14)	0.0984	53.71 (±9.79)	54.69 (±9.21)	0.9451
Body mass index (kg/m^2)	35.55 (±5.96)	37.77 (±8.74)	0.4030	35.50 (±5.70)	36.63 (±8.90)	0.9242
	n (%)			n (%)
Female	32 (66.67)	51 (80.95)	0.1220	17 (54.84)	37 (82.22)	0.0193
Married	30 (62.50)	40 (63.49)	0.8441	23 (74.19)	31 (70.45)	0.7979
Occupation			0.6410			0.8504
Professional	24 (52.17)	38 (63.33)		18 (60.00)	29 (65.91)
Clinical	8 (17.39)	7 (11.67)		3 (10.00)	4 (9.09)
Clerical	8 (17.39)	10 (16.67)		6 (20.00)	9 (20.45)
Technical	5 (10.87)	5 (8.33)		2 (6.67)	2 (4.55)
Other	1 (2.17)	0 (0.0)		1 (3.33)	0 (0.0)
Education			0.4148			0.5362
High school or GED or vocational training	4 (8.33)	3 (4.76)		1 (3.23)	0 (0.0)
Some college or bachelor’s degree	26 (54.17)	29 (46.03)		12 (38.71)	20 (45.45)
Postgraduate training or degree	18 (37.50)	31 (49.21)		18 (58.06)	24 (54.55)
Race			0.0669			0.9012
Non-Hispanic white	43 (89.58)	47 (74.60)		26 (83.87)	34 (75.56)
Non-Hispanic black	2 (4.17)	12 (19.05)		3 (9.68)	5 (11.11)
Asian	3 (6.25)	4 (6.35)		2 (6.45)	3 (6.67)
More than 1 race	0 (0.0)	0 (0.0)		0 (0.0)	1 (2.22)
Not reported	0 (0.0)	0 (0.0)		0 (0.0)	2 (4.44)
Ethnicity			1.00			0.3732
Hispanic	0 (0.0)	0 (0.0)		1 (3.23)	4 (8.89)

^a Values may not sum for the sample due to missing data.

Table 4. Comparison of the least squares mean (±SE) change in measures at 12 – and 18-months across four intervention sequences.

Self-Regulatory Measures	GLB/GLB^a	GLB+/GLB + ^b	P-value ^c	GLB/GLB + ^d	GLB+/GLB ^e	P-value ^c
Self-efficacy: Reducing Calorie Intake
Change: 4–12 months	−1.16 (±0.56)	−0.39 (±0.52)	0.3119	−1.23 (±0.72)	0.53 (±0.61)	0.0620
Change: 12–18 months	0.37 (±0.66)	−0.93 (±0.57)	0.1358	−1.78 (±0.86)	−1.15 (±0.73)	0.5792
Self-efficacy: Reducing Fat Intake
Change: 4–12 months	−1.89 (±1.08)	0.93 (±0.99)	0.0560	−1.17 (±1.36)	1.10 (±1.18)	0.2072
Change: 12–18 months	1.40 (±1.26)	−3.01 (±1.10)**	0.0088	−1.17 (±1.64)	−3.37 (±1.41)	0.3094
Self-efficacy: Sticking to Healthy Eating
Change: 4–12 months	−0.92 (±0.54)	0.31 (±0.49)	0.0949	−0.37 (±0.68)	0.76 (±0.58)	0.2057
Change: 12–18 months	−0.08 (±0.64)	−2.61 (±0.56)***	0.0031	−1.50 (±0.83)	−1.05 (±0.70)	0.6796
Self-efficacy: Sticking to Exercise
Change: 4–12 months	−2.98 (±1.16)**	0.75 (±1.06)	0.0179	−3.02 (±1.47)	−0.43 (±1.26)	0.1817
Change: 12–18 months	2.78 (±1.36)	−1.79 (±1.18)	0.0117	−3.01 (±1.78)	−0.58 (±1.52)	0.2979
Self-efficacy: Making Time for Exercise
Change: 4–12 months	−1.25 (±0.64)	0.38 (±0.58)	0.0609	−1.84 (±0.82)	0.21 (±0.69)	0.0546
Change: 12–18 months	0.59 (±0.75)	−0.77 (±0.65)	0.1719	−1.85 (±0.98)	−0.67 (±0.83)	0.3608
Physical Activity Self-regulation Skills
Change: 4–12 months	−0.89 (±1.41)	0.74 (±1.29)	0.3956	−1.53 (±1.79)	−2.00 (±1.52)	0.8411
Change: 12–18 months	−2.51 (±1.66)	−6.39 (±1.45)***	0.0800	−3.03 (±2.17)	−0.17 (±1.85)	0.3083
Self-efficacy: Weight Management
Change: 4–12 months	−7.07 (±3.72)	0.51 (±3.39)	0.1332	−4.37 (±4.78)	0.58 (±4.04)	0.4300
Change: 12–18 months	1.78 (±4.39)	−10.38 (±3.81)**	0.0372	−4.32 (±5.81)	2.07 (±4.88)	0.4001
Goal Commitment to Losing Weight
Change: 4–12 months	−1.55 (±0.54)**	−1.47 (±0.49)**	0.9109	−1.51 (±0.68)	−1.69 (±0.58)**	0.8391
Change: 12–18 months	−0.26 (±0.64)	−1.07 (±0.56)	0.3402	−0.31 (±0.82)	−1.43 (±0.70)	0.3059
Total Hope Score
Change: 4–12 months	−0.50 (±0.78)	−0.57 (±0.72)	0.9468	−1.57 (±1.01)	0.73 (±0.85)	0.0831
Change: 12–18 months	0.99 (±0.93)	−2.13 (±0.82)**	0.0119	−1.67 (±1.23)	−2.64 (±1.03)	0.5479
Dietary Measures
Energy (kcal)
Change: 4–12 months	117 (±71)	25 (±65)	0.3383	−149 (±90)	3 (±79)	0.2040
Change: 12–18 months	22 (±84)	−20 (±74)	0.7083	67 (±110)	3 (±96)	0.6584
Total fat (% energy)
Change: 4–12 months	1.45 (±0.84)	0.54 (±0.76)	0.4242	1.33 (±1.06)	0.79 (±0.92)	0.6975
Change: 12–18 months	−0.37 (±0.99)	1.22 (±0.86)	0.2261	−0.95 (±1.29)	−0.20 (±1.13)	0.6596
Protein (% energy)
Change: 4–12 months	−0.22 (±0.36)	−0.10 (±0.33)	0.8014	−1.31 (±0.46)**	−0.32 (±0.40)	0.1040
Change: 12–18 months	−0.24 (±0.43)	−0.12 (±0.38)	0.8298	0.08 (±0.56)	0.09 (±0.49)	0.9880
Carbohydrate (% energy)
Change: 4–12 months	−1.45 (±0.90)	−0.76 (±0.82)	0.5720	0.62 (±1.15)	−0.62 (±1.00)	0.4163
Change: 12–18 months	0.42 (±1.06)	−1.17 (±0.93)	0.2612	0.55 (±1.40)	0.27 (±1.22)	0.8800
Fiber (grams)
Change: 4–12 months	0.54 (±1.07)	0.47 (±0.97)	0.9622	−0.06 (±1.36)	1.64 (±1.18)	0.3451
Change: 12–18 months	−0.08 (±1.26)	−0.48 (±1.10)	0.8107	0.25 (±1.65)	−1.23 (±1.44)	0.4983
Total sugars (grams)
Change: 4–12 months	−3.66 (±5.23)	2.72 (±4.02)	0.5270	−6.88 (±5.62)	0.24 (±4.89)	0.3397
Change: 12–18 months	3.66 (±5.23)	−2.37 (±4.58)	0.8521	2.76 (±6.86)	2.04 (±5.97)	0.9369
Moderate Intensity Physical Activity (total minutes across 7 days)
Change: 4–12 months	21.07(±27.63)	9.86 (±24.85)	0.7632	−37.43 (±35.18)	−2.02 (±31.76)	0.4554
Change: 12–18 months	−50.66 (±33.92)	−42.87 (±29.58)	0.8627	−92.99 (±46.60)*	−15.97 (±38.47)	0.2032

^a Intervention sequence Group Lifestyle Balance (GLB) from baseline to 4-months (n = 48) and GLB from 5 – to 18-months (n = 29). Some participants did not complete the 18-month assessment due to pandemic-related restrictions in 2020.

^b Intervention sequence Group Lifestyle Balance Plus (GLB+) from baseline to 4-months (n = 62) and GLB + from 5 – to 18-months (n = 41)

^c Comparison of the mean change between the two intervention sequences. A p-value < 0.0167 used to indicate statistical significance to account for the Bonferroni correction of three between – and within-group comparisons.

^d Intervention sequence GLB from baseline to 4-months (n = 31) and GLB + from 5 – to 18-months (n = 17)

^e Intervention sequence GLB + from baseline to 4-months (n = 45) and GLB from 5 – to 18-months (n = 23)

**P-value < 0.01; ***P-value < 0.001

Hoffmann, T. C., Glasziou, P. P., Boutron, I., Milne, R., Perera, R., Moher, D., Altman, D. G., Barbour, V., Macdonald, H., Johnston, M., & Lamb, S. E. (2014). Better reporting of interventions: Template for intervention description and replication (TIDieR) checklist and guide. BMJ, 348(mar07 3), g1687. https://doi.org/10.1136/bmj.g1687

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