Obesity and depression are often comorbid conditions, with an apparent bi-directional relationship. Obesity at baseline has been shown to increase the risk of onset of depression and depression at baseline increased the odds for developing obesity. Less is understood about the impact of obesity on depression outcomes.

Our hypothesis was that obesity (BMI >= 30) and morbid obesity (BMI >= 40) would have negative effects on depression remission rates after six months of enrollment into collaborative care management (CCM).

This study was retrospective analysis of 1,111 depressed patients with a PHQ-9 score of 10 or greater that were enrolled in CCM. Of these patients, 81.5% (1,587) had BMI data available and only 27.4% (435) were of a normal BMI (BMI>=15 and < 25.0), while 44.7% (710) were obese (BMI >= 30). Multivariate analysis for the odds ratio of achieving remission at six months demonstrated that the patient's BMI at baseline was not a risk factor for depression outcome at six months. The clinical factors of recurrent depression, PHQ-9 score and an abnormal MDQ score were found to be statistically significant with an inverse relationship to remission at six months, an observation that had been shown in prior studies.

CCM for depression has been shown to be effective for improving depression outcomes. While obesity was common in our study population, it was reassuring, based on this study that six month depression treatment outcomes do not appear to be significantly impacted by the patient's baseline BMI.