Patient predictors of weight loss following a behavioral weight management intervention among US Veterans with severe obesity

Abstract

Purpose: Identification of patient characteristics that are associated with behavioral weight loss success among bariatric surgery candidates could inform selection of optimal bariatric surgery candidates. We examined the associations between psychosocial characteristics and weight loss in a group of Veterans with severe obesity who participated in a behavioral weight loss intervention.

Methods: The MAINTAIN trial involved a 16-week weight loss program followed by randomization among participants losing at least 4 kg to a maintenance intervention or usual care. This secondary analysis was performed on Veterans who participated in the 16-week weight loss program and met NIH criteria for bariatric surgery (body mass index [BMI] 35.0-39.9 with at least 1 obesity-related comorbidity or BMI ≥ 40). Unadjusted and adjusted associations between baseline patient characteristics and weight loss during the 16-week induction phase were evaluated with linear regression. Missing weight measurements were multiply imputed, and results combined across ten imputations.

Results: Among the 206 patients who met inclusion criteria, mean initial BMI was 40.8 kg/m2 (SD 6.0), and mean age was 59.2 years (SD 9.4). Approximately 20% of participants were female, 51.5% were Black, and 44.7% were White. Estimated mean 16-week weight loss was 5.16 kg (SD 4.31). In adjusted analyses, greater social support and older age were associated with greater weight loss (p < 0.05). None of the nine psychosocial characteristics we examined were associated with greater weight loss.

Conclusions: Understanding and strengthening the level of social support for bariatric surgery candidates may be important given that it appears to be strongly correlated with behavioral weight loss success.

Level of evidence: Level II, Evidence obtained from well-designed controlled trials without randomization.

Trial registration: ClinicalTrials.gov NCT01357551 https://ichgcp.net/clinical-trials-registry/NCT01357551 .

Keywords: Bariatric surgery; Clinical trials; Severe obesity; Weight loss.

Conflict of interest statement

CONFLICT OF INTEREST

Effort on this study and manuscript was made possible by a VA Career Development Award to Dr. Funk, an NIH career development award to Dr. McVay, and a Research Career Scientist award to Dr. Voils. This work was also supported by the Center of Innovation for Health Services Research in Primary Care at the Durham VA Medical Center. The views represented in this article represent those of the authors and not those of the DVA or the US Government. The authors declare no conflicts of interest related to these funding sources.

Figures

Figure 1.. Patient Flow for Participants with Severe Obesity

a Exclusion criteria determined by data pull included most recent serum creatinine >2.0 mg/dL in men or >1.7 mg/dL in women; liver disease; type 1 diabetes; most recent hemoglobin A1c, in past six months ≥12%; average systolic blood pressure over the past year of ≥ 160 mmHg and most recent BP ≥ 160 mmHg; history of weight loss surgery, dementia, severe psychiatric illness, or substance abuse b N=10,807 were mailed letters; n=38 were mailed letters as well as being self-referred; n=239 were self-referred with no letter sent c Obtained by subtraction d Potential reasons for ineligibility assessed by telephone included: body mass index (BMI) <30 kg/m2 based on self-reported weight and height (reduced threshold to allow for error in reporting); self-reported age < 18 or > 75; weight loss ≥10 pounds in the previous 3 months; current enrollment in a lifestyle program; history of weight loss surgery; current use of weight loss medication or appetite suppressant; pregnancy or plan to become pregnant in upcoming 6 months, breastfeeding, or lack of birth control if premenopausal (female); organ transplant recipient; type 1 diabetes; heart disease with new treatment in past 3 months; liver disease; cancer not in remission; pacemaker or defibrillator due to use of bioelectronic impedance scale; major depression or emotional problems that would prevent following a diet closely or interacting with others in a group environment; illicit drug use or alcohol problems in the past year; inability to stand for study measurements; desire to lose weight; agreement to attend study visits; access to telephone; reliable transportation e N=2 of the n=267 ineligibles at phone screen (1 due to BMI, and 1 due to age) are included in both the “Scheduled for in-person consent and screening” and “In-person consent and screening” boxes. One was ineligible at phone screen due to BMI < 30 kg/m2, but then was erroneously re-screened in-person and excluded at that point for the same reason. The second was listed as excluded due to age > 75 at both phone and in-person screen. Both exclusions were erroneous as the patient was 75 at both time points; however, the patient was not included in study after the in-person screen.