Effect of Integrated Behavioral Weight Loss Treatment and Problem-Solving Therapy on Body Mass Index and Depressive Symptoms Among Patients With Obesity and Depression: The RAINBOW Randomized Clinical Trial

Abstract

Importance: Coexisting obesity and depression exacerbate morbidity and disability, but effective treatments remain elusive.

Objective: To test the hypothesis that an integrated collaborative care intervention would significantly improve both obesity and depression at 12 months compared with usual care.

Design, setting, and participants: The Research Aimed at Improving Both Mood and Weight (RAINBOW) randomized clinical trial enrolled 409 adults with body mass indices (BMIs) of 30 or greater (≥27 for Asian adults) and 9-item Patient Health Questionnaire (PHQ-9) scores of 10 or greater. Primary care patients at a health system in Northern California were recruited from September 30, 2014, to January 12, 2017; the date of final 12-month follow-up was January 17, 2018.

Interventions: All participants randomly assigned to the intervention (n = 204) or the usual care control group (n = 205) received medical care from their personal physicians as usual, received information on routine services for obesity and depression at their clinic, and received wireless physical activity trackers. Intervention participants also received a 12-month intervention that integrated a Diabetes Prevention Program-based behavioral weight loss treatment with problem-solving therapy for depression and, if indicated, antidepressant medications.

Main outcomes and measures: The co-primary outcome measures were BMI and 20-item Depression Symptom Checklist (SCL-20) scores (range, 0 [best] to 4 [worst]) at 12 months.

Results: Among 409 participants randomized (mean age of 51.0 years [SD, 12.1 years]; 70% were women; mean BMI of 36.7 [SD, 6.4]; mean PHQ-9 score of 13.8 [SD, 3.1]; and mean SCL-20 score of 1.5 [SD, 0.5]), 344 (84.1%) completed 12-month follow-up. At 12 months, mean BMI declined from 36.7 (SD, 6.9) to 35.9 (SD, 7.1) among intervention participants compared with a change in mean BMI from 36.6 (SD, 5.8) to 36.6 (SD, 6.0) among usual care participants (between-group mean difference, -0.7 [95% CI, -1.1 to -0.2]; P = .01). Mean SCL-20 score declined from 1.5 (SD, 0.5) to 1.1 (SD, 1.0) at 12 months among intervention participants compared with a change in mean SCL-20 score from 1.5 (SD, 0.6) to 1.4 (SD, 1.3) among usual care participants (between-group mean difference, -0.2 [95% CI, -0.4 to 0]; P = .01). There were 47 adverse events or serious adverse events that involved musculoskeletal injuries (27 in the intervention group and 20 in the usual care group).

Conclusions and relevance: Among adults with obesity and depression, a collaborative care intervention integrating behavioral weight loss treatment, problem-solving therapy, and as-needed antidepressant medications significantly improved weight loss and depressive symptoms at 12 months compared with usual care; however, the effect sizes were modest and of uncertain clinical importance.

Trial registration: ClinicalTrials.gov Identifier: NCT02246413.

Conflict of interest statement

Conflict of Interest Disclosures: Dr Lavori reported receiving personal fees from Palo Alto Medical Foundation Research Institute. No other disclosures were reported.

Figures

Figure 1.. Enrollment, Randomization, and Follow-up of the Study Patients

BMI indicates body mass index (calculated as weight in kilograms divided by height in meters squared); PHQ-9, 9-Item Patient Health Questionnaire; SCL-20, 20-item Depression Symptom Checklist.

Figure 2.. Effect Modification Analysis

Body mass index was calculated as weight in kilograms divided by height in meters squared. The scores for the SCL-20 were calculated using the response categories: “not at all,” “a little bit,” “moderately,” “quite a bit,” and “extremely” that were assigned the scores of 0, 1, 2, 3, and 4, respectively. The average scores for the 20 items range from 0 (not depressed at all) to 4 (extremely depressed). The mean adjusted difference and 95% CIs were obtained from linear mixed-effects models accounting for the random effects of repeated measures and primary care physicians and adjusting for the baseline value of the outcome of interest and randomization covariates (clinic, age, sex, race/ethnicity, education level, use of any antidepressant medications at the time of enrollment, and number of hospitalizations during the 12 months prior to randomization). The P values for the interaction terms of the modifier and study group were obtained from general least-square models that accounted for repeated measures and were adjusted for the baseline value of the outcome of interest, randomization covariates as listed above, the main effect of the effect modifier (if not a randomization covariate), and the main effect of the study group.