ENCOURAGEing Start: A Quasi-experimental Trial on Pre-Op Physical Activity Intervention for Bariatric Surgery Candidates

doi:10.21203/rs.3.rs-2958124/v1

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ENCOURAGEing Start: A Quasi-experimental Trial on Pre-Op Physical Activity Intervention for Bariatric Surgery Candidates

https://doi.org/10.21203/rs.3.rs-2958124/v1

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Introduction

The American Society for Metabolic and Bariatric Surgery recommends pre- and post-operative physical activity (PA). However, there are no effective standardized PA programs incorporating a behavioral change approach for bariatric surgery patients. A novel pre-operative PA intervention ENCOURAGEing Start was developed and piloted to assist patients in reducing barriers to PA and encouraging positive PA habits.

Methods

This single arm pilot study recruited patients (n=27, BMI = 47.1 ± 6.2) from the Victoria General Hospital’s Centre for Metabolic and Bariatric Surgery in Winnipeg, Manitoba between September 2017 and May 2018. A time-series quasi-experimental design was used. The 16-week intervention took place at the University of Manitoba’s Active Living Centre. The primary outcome was a six-minute walk test (6MW), a measure of functional ability and predictive of post-surgical weight loss and maintenance. Secondary outcomes included fitness, cardiovascular disease risk and mental health. Outcomes were evaluated at baseline, 8 weeks, and 16 weeks.

Results

Ten patients completed the intervention. Clinically significant (p≤0.05) differences in the 6MW (457.21 vs 497.58 m, p=0.002), indirect 1RM leg press (283.72 vs 331.60 lb, p<0.001), sit-to-stand (12.78 vs 14.82, p<0.01), and quality of life (181.89 vs 195.96, p=0.028) were identified for completers.

Conclusions

The ENCOURAGEing Start intervention enhanced markers linked to long-term post-surgery outcomes, including a 10.7% increase in 6MW. This feasible program showed similar effect size to more resource intensive interventions, including those in Canada. A larger study with a minimum of 55 participants should be undertaken to assess the sustainability of these effects.

Six-minute walk test

pre-operative intervention

long-term outcomes

obesity surgery

functional ability

Strong evidence suggests that physical activity (PA) improves short- and long-term surgical outcomes for bariatric surgery/weight-loss surgery (WLS) patients. These include: higher and sustained weight loss (1), quality of life (2), preservation of lean body mass (3) and reduced length of hospital stay (4). While the American Society for Metabolic and Bariatric Surgeons considers preoperative health behavioral intervention a standard of care (5), the specific parameters and structure of such a program have not been developed. Due to a lengthy wait time for WLS and the substantial interim healthcare costs of obesity (6), the development of an upstream program to develop patients' physical activity and self-efficacy is worthwhile. The preparatory phase standard to any WLS program, including consultation with a multidisciplinary team with behavior change education, is an opportune time for teaching physical activity skills.

Most PA interventions for WLS patients focus on direct supervision during highly structured and prescribed exercise (7–8) with no integrated behavior change techniques (BCT) or education beyond usage of facility-based equipment. Although health-behavior BCTs are well established (9–11), it is evident that most PA interventions are not designed with these in mind. Notably, we are unaware of any pre- or post-operative PA interventions for WLS patients that integrate BCTs such as social support and comparison (12), barrier identification/problem solving, and environmental restructuring (10). Conversely, there is often no social dynamic or peer modeling, and participants may work one-on-one with a fitness trainer (13) which may not address all psychosocial factors needed for lasting behavior change (14, 15). In addition to these methodological shortcomings, many pre-operative PA interventions necessitate significant logistical demands such as the cost of one-on-one supervision, usage of dedicated research space, or frequency of sessions (7–8, 16).

As such, we designed an efficient intervention that provided structured bouts of moderate-to-high-intensity PA while also integrating BCTs regularly. It was hypothesized that this comprehensive format would cause significant improvement in measures of physical fitness, quality of life and symptoms of depression. A pilot project for this intervention was developed in partnership between the University of Manitoba and Winnipeg Regional Health Authority. The goal was to determine an effect size for the intervention and to calculate a sample size needed to demonstrate a statistically significant change for the primary outcome in a future randomized controlled trial.

Participants

Patients were recruited from the Victoria General Hospital’s Centre for Metabolic and Bariatric Surgery (CMBS). CMBS is based in Winnipeg and serves as Manitoba’s provincial bariatric center. As such, like many Canadian Bariatric institutions, its catchment area is vast with a patient community potentially being 1000 kilometers away. The CMBS patient eligibility criteria includes age (18–59), BMI (40–55 or 35-39.9 with obesity-related comorbidities), being mobile and able to perform PA, and previous attempts to lose weight and improve health through diet and exercise. CMBS patients received information about the intervention from CMBS staff during standard preoperative appointments and had the opportunity to complete a Permission to Contact form to self-select into the intervention. Patients were required to attend sessions in person which limited participants to those living in Winnipeg or the surrounding area that were willing to travel. An exclusion criterion was body weight (> 350 lb) due to manufacturer specifications of exercise equipment. Informed consent was obtained from all individual participants included in the study.

All procedures performed in this study involving human participants were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. Ethics approval for this study was granted by the University of Manitoba Research Ethics Board (reference #HS19982; H2016:283) and the Victoria General Hospital Foundation Research and Evaluation Office. Clinicaltrials.gov registration number: NCT03049696. Registration date: February 2017.

Intervention

The intervention and data collection occurred at the University of Manitoba’s Active Living Centre (ALC). An overview of the intervention is shown in Table 1, followed by explanation of its components. No incentives were provided for attendance or participation at any component of the program. Guiding documents used in the delivery of each session enabled standardization of all aspects of the intervention.

Table 1

Intervention structure
	Structured components	Unstructured components
Weeks 1–8	Day A: Walk and Talk session weekly, in addition to an education seminar in weeks 1, 3, 5, 7. Day B: Instructor-led structured exercise. Weekly: Homework assignments.	University recreation facilities membership which includes access to exercise equipment, track and pool as well as group fitness classes.
Week 9–16	Day A: 60-minute window of time where instructor is available to assist participants or answer questions. Every two weeks: instructor contacts any participants who did not attend as above, in order to provide motivation and guidance.

Walk & Talk sessions promoted social support and behavior modification while gaining added health benefits of moderate-intensity exercise with short bouts of vigorous intensity exercise. During the 45-minute session, participants walked in pairs or trios on a track while discussing provided health-related questions. Upon completing each question, the grouping would do a hot lap, where they walked at a pace that would leave them breathing harder by its conclusion. Twice throughout the session, groupings would step off the track to engage in a checkstop with the instructor, where they learned or demonstrated a skill, or discussed a question in more depth. Early checkstops taught skills such as measuring heart rate, and then seeing if the speed of a regular lap puts the participant in a moderate-intensity heart rate zone. Later checkstops had participants apply learnings, such as providing suggestions to their grouping to reduce their barriers to PA or demonstrating a calisthenic exercise. Chairs were available to rest on it if needed. Groupings who felt unable to walk for a majority of the time used upright stationary bikes or elliptical machines as an alternative. Figure 1 illustrates Walk & Talk information given to participants.

Education seminars took place in weeks 1, 3, 5, 7 in a classroom setting. Topics included benefits of PA, PA trends, and information on PA opportunities from facility-based (staff certification, costs and contracts, services) to community-based opportunities (finding equipment, active transport, leisure activities).

Instructor-led structured exercise allowed participants to experience a variety of PA options, which may have otherwise presented barriers of self-confidence and social support. These included machine-based resistance training, yoga, TRX® suspension training, recreational sports, cycle fitness, and Zumba® dance fitness.

Homework assignments were assigned and integrated into the following week's Walk & Talk session. Examples include participants creating a weekly PA logsheet or trying a PA opportunity near their home and discussing their experience to the group.

These components promoted BCTs such as behavioral practice/rehearsal and social comparison (10). BCTs were also targeted during specific program content. For example, the fourth week of Walk & Talk questions focused on review of past behavior, and one question prompted focus on past success (10):

People sometimes feel that they cannot be physically active because they don’t have the skill. Talk about the last skill you learned. Why did you learn it? What steps did you take? This doesn’t need to be exercise-related, think of anything from renovations to learning a musical instrument!

Checkstops and instructor-led exercise focused more on physically-based behavior change techniques such as instructions on how to perform a behavior or demonstration of the behavior (11).

Measures

The primary outcome was the 6 minute walk test (6MW), a validated measure of functional capacity for several populations and a commonly-used indicator in pre- and post-BS studies (18). 6MW is relatively easy to administer and correlates with aerobic fitness (VO₂max) (19).

Secondary outcomes included (1) anthropometric measurements (height, weight, BMI), neck circumference, waist and hip circumference, and body composition; (2) strength measurements (sit to stand, 1RM leg press, grip strength); (3) physical activity level (Actigraph accelerometer); (4) cardiovascular disease risk measurement (resting and post-exercise blood pressure, small and large artery elasticity) (19); (5) frailty measurement (five-meter gait test and Modified Fried Questionnaire-physical activity/nutrition/exhaustion) (20); (6) patient quality of life/satisfaction/mental health and depression surveys; (7) self-compassion, anxiety and physical activity questionnaires (21–24).

Another aspect of the research, to be reported in the future, examined the cytokine profile of participants and required bloodwork before and after the intervention.

Statistical Approach

The targeted sample size was 48 participants. This would provide sufficient power for the primary outcome (6MWT) based on a conservative sample size calculation (two-tailed, 90% power) and dropout rate of 40%. Three cohorts were planned to support recruitment feasibility based on ALC resources and the number of patients attending the CMBS seminar. Patients were assigned into the next available cohort once their baseline appointment was completed. The study design did not require blinding of participant or researcher.

A Kolmogorov-Smirnov test was used to determine the distribution of individual baseline and 16-week data for participants who attended baseline, 8-week and 16-week data collection appointments. A Student's T-test (parametric) was performed on that data using baseline and 16-week time points. Only participants who completed the protocol were included in the pre-post assessment. No imputation of data was done, as all participants included in the analysis completed the protocol as intended. Analysis was done using SPSS software v26 (IBM Corp., Armonk, N.Y., USA). The null hypothesis was rejected at p ≤ 0.05.

The participant flow chart is presented in Fig. 2 and baseline characteristics of participants in Table 2. There was no significant difference in the primary outcome at baseline between completers and non-completers. The post-intervention analysis did not include an intention-to-treat, as the 16-week data for participant lost to follow-up was unavailable. No adverse or unintended effects attributable to the intervention were observed. The characteristics and pre-post changes of participants completing all baseline and 16-week appointments are shown in Table 3. The primary outcome of 6MW increased significantly (p = 0.006) by 54 ± 34 m (10.7%). Body fat (%) decreased significantly (0.89%, p = 0.030) at 16-week appointments. The other fitness-related secondary outcome to increase significantly was the 30 second chair stand (3.7 ± 1.9, p = 0.002). Participants increased leg press by a mean of 31.4% (p = 0.012). The Laval Questionnaire improved by 35 ± 37 (p = 0.045). PHQ-9 scores decreased from a moderate (10–14) to mild (5–9) range, indicating reduction in depressive symptoms (p = 0.039).

Table 2

Characteristics and scores of participants completing both baseline appointments
	All participants (n = 20)	Completers (n = 7)	Lost to follow-up (n = 13)
6 minute walk (m)	445 ± 81	501 ± 37	417 ± 84
Age (years)	47.9 ± 8.9	46.1 ± 5.9	44.2 ± 8.2
Females (#)	17	5	12
BMI	47.3 ± 5.6	44.5 ± 6.6	48.7 ± 4.8
Body fat (%)	48.7 ± 7.2	45.3 ± 8.8	50.4 ± 6.0
30 second chair stand (# reps)	12.6 ± 3.6	12.6 ± 3.2	12.6 ± 4.0
Indirect 1RM leg press (kg)	126 ± 36	139 ± 37	119 ± 34
Grip strength (kg)	32.8 ± 13.6	27.8 ± 4.5	33.5 ± 15.9
Resting systolic BP (mmHg)	145 ± 17	130 ± 16	152 ± 12
Resting diastolic BP (mmHg)	78 ± 12	76 ± 12	80 ± 12
Rasmussen Disease Score	2.13 ± 1.26	3.3 ± 1.5	1.93 ± 1.2
5 meter gait (s)	5.36 ± 1.48	4.78 ± 0.21	5.41 ± 1.66
Laval Quality of Life	183 ± 50	181 ± 46	185 ± 54
PHQ9	8.9 ± 7.1	12.4 ± 7.7	7.1 ± 6.4
HADS Anxiety composite score	7.3 ± 4.8	7.6 ± 5.3	7.2 ± 4.7
HADS depression composite score	5.6 ± 3.8	6.1 ± 2.8	5.3 ± 4.3

Table 3

Characteristics and pre-post changes of participants completing all baseline and 16-week appointments (n = 7)
	Baseline	16 week	Mean	P value	CI Lower	CI Upper
	Mean ± SD			P value	CI Lower	CI Upper
6 minute walk (m)	501 ± 373	555 ± 54	54 ± 34	0.006	-85.5	-22.0
BMI	44.5 ± 6.6	44.5 ± 7.0	-0.04 ± 0.75	0.885	-0.655	0.741
Body fat (%)	45.3 ± 8.8	44.4 ± 9.1	-0.89 ± 0.83	0.030	0.117	1.65
30 second chair stand (# reps)	12.6 ± 3.2	16.3 ± 3.0	3.7 ± 1.9	0.002	-5.46	-1.97
Indirect 1RM leg press (lb)	308 ± 82	405 ± 74	98 ± 72	0.012	-164	-31.1
Grip strength (kg)	27.8 ± 4.5	29.5 ± 6.9	-1.7 ± 2.0	0.430	-6.66	3.33
Resting systolic BP (mmHg)	130 ± 16	136 ± 17	5.4 ± 15	0.361	-18.9	8.00
Resting diastolic BP (mmHg)	76 ± 12	79 ± 7	3 ± 12	0.475	-14.4	7.59
Rasmussen Disease Score	3.0 ± 0.7	1.8 ± 2.1	-1.2 ± 1.6	0.178	-0.840	3.24
5 meter gait (s)	5.03 ± 0.37	4.72 ± 3.1	-0.3 ± 0.3	0.077	-0.048	0.654
Laval Quality of Life	189 ± 46	225 ± 38	35 ± 37	0.045	-68.67	-1.05
PHQ9	12.4 ± 7.7	8.3 ± 5.9	-4.4 ± 4.2	0.039	.277	8.01
HADS Anxiety	7.6 ± 5.3	5.4 ± 5.4	-2.1 ± 3.6	0.169	-1.21	5.50
HADS Depression	6.1 ± 2.8	3.9 ± 3.2	-2.3 ± 3.8	0.160	-1.20	5.78

The primary outcome of 6MW increased significantly by 10.7% is greater than the 27.5 ± 10.3 m (5.9% mean) seen in Kwok’s 2016 thesis work on pre-operative PA intervention for CMBS patients. Our post-intervention 6MW scores are similar to or greater than Baillot (Canada-situated) or Simmons’ (American-situated) pre-operative bariatric PA interventions (16, 25), which are themselves similar to 6 month post-operative scores with no intervention (26, 27). Minimal clinically important difference for the 6MW in a pre-surgical bariatric population is unknown, but a 30–80 m increase may be clinically important across multiple pathological patient groups (28).

The indirect 1TM leg press (lb), a measure of muscular strength may have a protective effect against the significant loss of fat-free mass and skeletal muscle mass typically seen after weight loss surgery (29). Participants experienced an increase of leg press by a mean of 31.4% (p = 0.012). The other fitness-related secondary outcome to increase significantly was the 30 second chair stand. This test is an indicator of balance and muscular endurance. The effect size was similar to Baillot's more intensive thrice-weekly intervention (2, no SD given) (16).

PHQ-9 scores decreased from a moderate (9–13) to mild (5–9) range, indicating reduction in depressive symptoms (p = 0.039). The Laval Questionnaire, a validated measure of health-related quality of life in patients with morbid obesity, improved significantly. As symptoms of depression and sedentary lifestyles have a bidirectional relationship (30), these effects may support increased post-operative PA.

Although past research has examined the use of PA interventions for improving outcomes in patients waiting for WLS, those interventions required direct supervision of participants during highly structured and prescribed exercise (7–8).Our approach utilized an efficient group approach in which up to 12 participants were managed by one staff, whereas other studies reported higher staff or time usage. For example, the Bari-Active study provided a structured environment focusing on a behavior change curriculum and allocated up to 4.5 hours of instructor time per participant (2). The EFIBAR intervention protocol, focused on individualized PA prescription and progression, requires 48 hours of instructor time per participant (13). Our format requires 1.2 hours of instructor time per participant assuming a cohort of 12. The PreSET intervention (16) did not list an instructor to participant ratio, but total instructor time per cohort would be 42 hours compared to our 26 hours. Our intervention resulted in 6MW scores statistically similar to these other formats, with significantly less funding required. The 16-week cost for each participant in a cohort of 12 is $190, which includes certified fitness staff, 4-month facility access, and 15 minutes of instructor transition time before and after sessions. Efficiencies were also shown in secondary outcomes. Daniels et al. (31) provided approximately 18 times more structured resistance training than participants in this study for a slightly higher leg press improvement (36.2% vs 31.4%).

During the course of the intervention, 42% of participants met their individualized goals set by CMBS and were given a surgery date in the near future. These participants were unable to complete the program as intended and were therefore lost to the intervention's 8-week and/or 16-week data collection appointments. It is reasonable to believe that, had we been able to include data from these successful patients, effect sizes for several outcomes may have been larger. Our appointment scheduling was in contrast to other pre-operative physical activity interventions such as PreSET, which scheduled data collection relative to surgery date rather than at a predetermined week of the intervention. As a result, the PreSET interventions had no participants lost to follow-up (32, 33). That scheduling appears more appropriate for the variable timelines inherent to a surgical program and is a suggested methodological change for future implementations.

Initial recruitment was slower than expected as many CMBS patients were rural and declined participation for various reasons. Only 24% of new CMBS patients completed the Consent to Contact form. Several logistical delays such as securing gym access cards, training research staff, collecting baseline data, and securing space bookings within a dynamic facility (e.g., gyms were used for student exam writing) meant that many participants entered the intervention later in their CMBS program than planned.

The setting of a community fitness facility for a pre-surgical PA intervention is novel. To our knowledge, all other in-person pre-operative interventions have taken place in medical fitness facilities, hospitals, or university lab areas (2, 33–36). Though a robust set of emergency response procedures was in place through both facility staff and research staff, there were no adverse incidents. The versatility to operate the intervention in such a facility would maximize the number of potential sites, reduce cost, and presumably make its geographic location more central and ideal for participants. The program could also be run in an outdoor space - this was considered but discarded in this pilot trial due to the layout of the University grounds. We theorize that becoming comfortable in an active community space, rather than an inaccessible lab, may promote greater adoption of health behaviors. This would be particularly advantageous for the delivery of bariatric surgical programming in a Canadian setting where patients may be located remotely from their center. Consideration should also be given to integration of virtual/web-based intervention components. This may be an enhancement of an existing intervention component (e.g., an online discussion group between participants) or modification of the site-based format to support patients who were unable to participate due to geographic barriers.

These findings appear to be generalizable to the typical bariatric surgery patient. Baseline BMI, 6MW and 30 second chair stand scores are similar to other pre-surgical interventions. For example, our participants had a BMI of 47.3 ± 5.6, comparable to Kwok (46.9 ± 5.4), Baillot (46.6, no SD given) (37), Cassin (49.6 ± 8.5) (38).

Based on the positive physical and mental health effects of this single arm pilot study, we recommend that a larger study, with a minimum recruitment target of 55 participants, be undertaken using this generalizable, economical, standardized and effective ENCOURAGEing Start framework.

ACKOWLEGMENTS

We would like to thank the patients and Centre of Metabolic and Bariatric Surgery staff for their participation in this study.

ACKOWLEGMENTS

We would like to thank the patients and Centre of Metabolic and Bariatric Surgery staff for their participation in this study.

Ethics approval for this study was obtained from the University of Manitoba Research Ethics Board (reference #HS19982; H2016:283) and the Victoria General Hospital Foundation Research and Evaluation Office. All participants provided informed consent to participate in the study. The co-authors have given their consent for publication. The data and materials are available upon request. This research was supported by the Victoria General Hospital Foundation.

The authors have no conflicts of interest to declare. Alex Edye-Mazowita collected the data and wrote the manuscript. Dr. Wenjing He conducted the data analysis and reviewed the manuscript. Dr. Todd A. Duhamel contributed to the study design and data analysis. Dr. Krista Hardy conceived the study and provided supervision. Dr. Ashley Vergis was involved in the study design and manuscript review.

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No competing interests reported.

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ENCOURAGEing Start: A Quasi-experimental Trial on Pre-Op Physical Activity Intervention for Bariatric Surgery Candidates

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