Development of a Weight Maintenance Intervention for Bariatric Surgery Patients
Phase: NA
Conditions: Obesity, Morbid
Sponsor: VA Office of Research and Development

Development of a weight maintenance intervention for bariatric surgery patients 
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Title: Development of a weight maintenance intervention for bariatric surgery patients 
Principal Investigator: Corrine Voils, PhD  
Co-Investigators: Maren Olsen, PhD; Megan McVay, PhD; Luke Funk, MD;  
Sridharan Raghavan, MD, PhD 
 
Purpose. Bariatric surgery is the most effective treatment for patients with severe obesity, 
defined as class II obesity (body mass index [BMI] 35-39.9 kg/m2) with an obesity-related 
comorbidity or class III (BMI >40 kg/m2) obesity. When compared to non-surgical treatment 
options, bariatric surgery results in greater weight loss, comorbidity remission, and quality of life 
improvement, and is associated with an extended lifespan. Many patients regain weight 
following bariatric surgery, which is associated with recurrence of obesity-related comorbidities 
such as diabetes. A major factor in undesirable weight regain is suboptimal patient adherence to 
post-operative dietary and physical activity recommendations. To improve patient adherence to 
recommended lifestyle behaviors, effective behavioral interventions are needed. 
In this pre-post, within-subject pilot study, we will enroll Veterans one year following bariatric 
surgery and deliver an abbreviated behavioral weight loss maintenance intervention for 16 
weeks. Specific aims are: 
 
Aim 1: Refine telephone intervention scripts to address dietary, mobility, and behavioral 
issues specific to bariatric surgery patients.  
 
Aim 2: Evaluate feasibility of conducting a multi-site trial, as indicated by recruitment and 
outcome assessment rates.  
 
Aim 3: Evaluate intervention acceptability, as indicated by intervention adherence rates, 
pre-post changes in weight and process measures, and feedback from post-intervention 
qualitative interviews. 
 
The VA performs ~450 bariatric operations per year across 17-21 sites. In a recent State-of-
the-Art Conference on weight management co-led by Health Services Research and 
Development (HSR&D) and by our operations partner, the National Center for Health Promotion 
and Disease Prevention (NCP), the bariatric surgery committee strongly agreed that future 
priorities for VA include increasing the number of sites that offer bariatric surgery and identifying 
strategies to help veterans maintain weight loss resulting from surgery. Our intervention, if 
effective, can help increase VHA’s return on investment as the bariatric surgery volume 
increases over the next decade.  
 
Background and Significance. Our conceptual model (Table 1) specifies cognitive and 
behavioral factors involved in initiation and maintenance of health behaviors. This model was 
used to design the weight loss initiation and maintenance interventions of the two-phase 
MAINTAIN trial, which involved a weight loss initiation program followed by randomization to 
maintenance intervention or usual care among patients losing at least 4 kg in the initiation 
phase. In modifying the intervention for bariatric surgery patients, there will be a health behavior 
initiation phase to ensure that patients initiate the recommended health behaviors (e.g., 
increased protein intake, elimination of high-calorie beverages, monitoring of caloric intake). 
Following initiation of these health behaviors, the interventionist will teach patients skills to 
maintain those new habits, thereby reducing weight regain.  
 

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Table 1: Initiation and Maintenance Constructs 
Initiation 
Maintenance 
Self-regulatory focus: approach a more favorable 
health state 
Self-regulatory focus: avoid reverting to a less 
favorable health state 
Favorable expectations about future outcomes of 
the behavior change 
Satisfaction with outcomes of the behavior change 
Action self-efficacy 
Maintenance and recovery self-efficacy  
Goal setting/action planning   
Maintenance and relapse prevention planning  
Monitoring by interventionist and self 
Self-monitoring 
Social support derived from social network, 
interventionist, and other participants  
Social support derived primarily from social network 
 
Design. This pilot study will be a within-person, pre-post design involving a 16-week 
intervention delivered starting one year after surgery (Figure 2). Patient outcomes will be 
assessed at baseline and 16 weeks. Participants will continue usual follow-up care with their 
primary care physician. 
 
Figure 2: Study flow 
 
We will recruit patients from four VA sites that perform bariatric surgery (Table 2).  
 
Table 2: Bariatric Surgery Sites Agreeing to Participate in Pilot Intervention Study 
VA Hospital 
VISN
2015 Bariatric 
Surgery Volume 
2016 Bariatric 
Surgery Volume 
(estimated) 
VA Boston Healthcare System 
1 
25 
25 
VA Ann Arbor Healthcare System 
11 
55 
100 
VA Palo Alto Healthcare System 
21 
30 
40 
VA Long Beach Healthcare System 
22 
10  
20 
 
Patient eligibility criteria will be determined by electronic data abstraction using CDW:  
 
Bariatric surgery at one of the 4 VA sites 
 
Laparoscopic Roux-en-Y gastric bypass (RYGB) or laparoscopic vertical sleeve  
 
gastrectomy (SG) six to 18 months prior to the time of data pull 
 
No procedures to prevent gastric cancer 
 
No revisional bariatric surgery  
 
The list of patients meeting those criteria will also include full name, social security number, 
address, phone number, surgery type, and surgery date. Eligible patients will receive a 
recruitment letter from study staff at the Madison VAMC. Two weeks after recruitment letters are 
mailed, the project coordinator (PC) will call patients to confirm eligibility, describe the study and 
obtain telephone consent. If a patient consents to be in the study, a consent form will be sent to 
their address to review. Once patients have provided consent, the PC will administer several 
baseline measures orally and schedule patients for their first intervention call. This first 
screening, consent, and baseline measures call will not be audio-recorded.  Responses will be 
recorded in RedCap.  All subsequent intervention calls and participant interviews will be 
recorded but not transcribed.  Instead, relevant notes from the intervention calls and the 

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participant interviews will be recorded in RedCap. We will remind each participant that they are 
being recorded on each call, and obtain their verbal consent for recording. Patients may opt out 
of the study at any time, as indicated in our telephone scripts. 
 
Additional patient eligibility criteria will be determined by telephone screening: 
 
English as preferred language  
 
Regular access to a telephone 
 
No hearing impairment 
 
No cancer not in remission 
 
 
Maintenance intervention.  
The first intervention telephone call will occur one week following the baseline assessment. 
Calls will be made weekly in the first month (weeks 1, 2, 3, 4) and biweekly calls during months 
2-4 (weeks 6, 8, 10, 12, 14). The intervention will be scripted to ensure reproducibility and to 
facilitate dissemination and implementation.  
 
Intervention content. The goal of this intervention is to increase adherence to 
recommendations that patients are already receiving from their bariatric team as part of 
standard of care. The first 4 calls of the intervention will review key concepts typically taught to 
patients in a bariatric surgery program, including specific recommendations for diet, physical 
activity, and vitamin/mineral supplementation. Subsequent calls will address maintenance skill 
building and anticipatory problem solving based on the processes outlined in our conceptual 
model and operationalized in our MAINTAIN protocol. Relapse prevention planning will help 
patients identify situations in which overeating is common in the bariatric population (e.g., loss 
of control eating related to emotions, disinhibition). These four areas and their intervention 
implications are provided in Table 3.     
 
Table 3. Incorporating Behavior Maintenance Strategies into the Weight Maintenance 
Intervention 
 
Measures. Our tracking database will capture the number of recruitment letters mailed, number 
of recruitment calls attempted and completed, number of patients consented, number of 
intervention calls delivered, and number of outcome assessment calls completed. As each 
Strategy 
Intervention Implication 
Satisfaction with 
outcomes of 
behavior change 
 Patients list the perceived benefits and cost of having changed their behavior  
 Patients reflect on satisfaction with past outcomes 
Self-monitoring 
 Patients identify frequency of weighing  
 Patients identify method for logging weight 
 Patients develop threshold for determining when a lapse occurs and return to dietary 
self-monitoring if this threshold is exceeded 
Recovery self-
efficacy/relapse 
planning 
 Patients prepare contingency plans for high-risk situations 
 Patients imagine and role-play responses for hypothetical situations 
Primary source 
of support is 
social network 
 Patients identify supportive members of their social networks.  
 Patients share goals with spouses, friends, coworkers 
 Patients suggest specific supportive behaviors (e.g., check-in calls, exercise dates)  

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intervention call will be recorded, we will also have data on the duration of each call. The RD will 
record the amount of time spent preparing for the call and conducting any follow-up activities. 
The following measures will be administered by telephone at weeks 0 and 16. Each patient will 
receive $25 for each assessment. 
 
Recovery self-efficacy refers to confidence to get back on track once relapse has occurred. 
We will measure recovery self-efficacy for dietary behavior and physical activity separately 
using 3-item measures developed by Schwarzer.1 Response scales range from 1 (not at all true) 
to 4 (very true). Internal consistency for the diet measure of 0.93 has been reported, and 0.71 
for the exercise measure. 
 
Satisfaction with outcomes of weight loss. Five items will assess satisfaction with outcomes 
of changes in the domains of enjoyment of food, health, physical attractiveness, fit of clothes, 
physical fitness, ability to complete tasks requiring physical exertion, social life, and positive 
feedback about weight loss.2  Response scales range from -4 (I am extremely unhappy about 
this change) to +4 (I am extremely happy about this change). We obtained internal consistency 
of 0.86 in our MAINTAIN trial.3 
 
Self-monitoring of weight. A single item will assess frequency of self-weighing during the 
intervention (During the last four months, how often did you weigh yourself? Daily, nearly every 
day, 3 or 4 times a week, once or twice a week, 2 or 3 times a month, once a month, less than 
once a month, never) 
 
Weight from EMR.  We will calculate and report % weight loss and % excess weight loss, both 
from start of the intervention and prior to surgery, as these outcomes are important to bariatric 
surgeons.  
 
Dietary intake will be assessed with 24-hour recalls conducted by the intervention registered 
dietitian.  We will use the VA-approved Food Processor Software on (staff name) located in 
(location). 
 
Daily physical activity will be assessed by the short version of the International Physical 
Activity Questionnaire (IPAQ).4 Analyses will focus on total physical activity as well as walking 
given that moderate or vigorous physical activity may not be feasible for this population.  
 
Qualitative interviews to assess experience with the intervention. Semi-structured 
qualitative interviews will be conducted within two weeks of the final outcome assessment by Dr. 
Voils or McVay or the PC. A semi-structured interview guide will be created, organized around 
the theoretical constructs indicated in our model. We will conduct interviews with approximately 
20 patients. Participants will receive $25 for completing the qualitative interview. 
 
Analyses.  
 
Aim 1: Refine telephone intervention scripts to address dietary, mobility, and behavioral 
issues specific to bariatric surgery patients. 
 
During study start-up, the team will have weekly calls in which intervention content is 
discussed and modified (e.g., a threshold for indicating relapse will be identified). The RD will 
conduct self-study and receive training from Dr. Funk in dietary issues specific to bariatric 
surgery patients. All intervention calls will be recorded. Each week, Drs. Voils and McVay and 
the RD will meet to review calls. Dr. Funk will listen to a portion of the calls as well. All calls for 

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the first 5 patients enrolled will be reviewed so that changes to the script can be made if 
necessary. The script will be revised iteratively until the team feels that patients understand and 
can engage with the content. Changes may be made to enhance comprehension of intervention 
material, ability to engage in the recommended behavioral skills, or to address any clinical 
issues that are identified. The final product from this aim will be a standardized intervention 
script that will be used in a future IIR to evaluate the efficacy of the intervention. 
 
Aim 2: Evaluate feasibility of conducting a multi-site trial, as indicated by recruitment and 
outcome assessment rates.  
 
As stated previously, we will use an electronic data pull to identify patients who have had 
surgery as well as their surgery date. We will create a custom tracking database that will import 
data from the data pull and create a flag that alerts study staff when patients are due for each 
intervention call. We will examine the dates of surgery to determine how frequently cases are 
performed.  
From our tracking database, we will calculate the recruitment rate as [# of participants who 
consent to the study/# of patients to whom letters were mailed]. We will further identify the rate 
of drop-out following consent to inform allocation of effort to recruitment in the future IIR. The 
outcome assessment retention rate will be calculated as [#of participants who complete the 16-
week outcome assessment call /number who were eligible upon completion of the baseline 
assessment].  
 
Aim 3: Evaluate intervention acceptability, as indicated by intervention adherence rates, 
pre-post changes in weight and process measures, and feedback from post-intervention 
qualitative interviews. 
 
Intervention adherence. For intervention adherence, we will calculate for each participant 
the mean (and standard deviation) number of intervention calls that were completed. Given our 
previous experience with telephone-based interventions, we expect high rates of intervention 
adherence. In Dr. Voils’ CouPLES trial, which involved 10 monthly telephone calls, the mean 
number of completed patient calls was 7.9 out of 9. In MAINTAIN, the mean number of 
completed calls was 6.95 (SD=1.75) out of 8. 
Pre-post changes in quantitative measures. Weight measurements will be pulled from the 
VA CDW files.  For each patient, baseline weight will be defined as the closest weight prior to 
the baseline survey assessment.  We will assess the feasibility of this definition. Because of the 
shortened follow-up for this pilot, we anticipate patients will only have on average 1-3 follow-up 
weights.  We will examine descriptively change in weights as well as each survey construct that 
is measured during telephone-based assessments. For the psychosocial measures, we will 
calculate total scores according to author instructions. For all measures, we will calculate 
descriptive statistics and plot the baseline and follow-up weights/scores, which will provide 
descriptive information on whether and to what extent patients experienced change. From the 
descriptive data, we will determine how each construct is operationalized in this patient 
population (e.g., floor/ceiling effects, skewed or highly variable distributions, etc.). For each 
variable, we will calculate the standardized difference between means, which will enable us to 
compare magnitude of changes across different measures. Although we will not be powered to 
detect statistically significant differences, the confidence intervals will provide information on the 
potential range of effect sizes, which will inform the power analysis for the future IIR.  
Post-intervention qualitative interviews. We will use a directed form of qualitative content 
analysis to code the interview transcripts,5 which will include a priori codes (based on theoretical 
constructs discussed in the interview guide) and emergent codes (anything not covered by the 
initial codes). Participant reactions to the intervention will be organized for analysis by key 

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maintenance constructs (i.e., satisfaction with outcomes of behavior change, relapse 
prevention, self-monitoring, and social support) as well as suggested changes to the 
intervention. Dr. Voils and the PC will use consensus to develop the coding framework.6 They 
will first code transcripts independently and meet to resolve discrepancies through discussion 
until they agree on definitions and rules for applying the codes (a priori and emergent). They will 
use this process with half of the transcripts and review the findings with the rest of the research 
team. The PC will then code the remainder of the transcripts and revisit the prior transcripts to 
make sure that the codes were consistently applied. ATLAS.ti (v. 6.1) will be used to manage 
coding of transcripts.7  
 
Sample size considerations. A power calculation will not be performed given that we are not 
evaluating statistical significance of the intervention in this pilot; rather, we are seeking an 
indication of feasibility and acceptability. We will enroll 30 patients, which will be adequate to 
evaluate the feasibility and acceptability of the intervention.  
 
Safety Monitoring Plan. Study staff will report any adverse event or unanticipated problem to 
the PI immediately. Study staff will review all such events and determine the likelihood they 
were due to the study. The PI will report any serious, unexpected, and study-related adverse 
event or unanticipated problem to the local IRB according to the institution’s requirements. The 
IRB will review all adverse events during continuing review, which will occur at least annually. If 
a Veteran reports that they are suicidal during a phone call, we will use a standard script given 
to us by the Madison VA Research Office. 
 
 
 
 

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