How does change in depressive symptomatology influence weight change in patients with diabetes? Observational results from the Pathways longitudinal cohort.

BACKGROUND: Little is known about how change in depressive symptoms over time is associated with change in weight.
METHODS: Longitudinal associations between change in depression (Patient Health Questionnaire-9 [PHQ-9]) and weight (self-reported and chart abstracted) were examined in 2,600 patients with type 2 diabetes (mean age 62, SD = 11.6) who were surveyed by telephone in 2001-2002 and 5 years later as part of the Pathways study. Mixed effects regression analyses compared a) patients with persistently low depression symptoms with those whose depression worsened (increased at least 5 points on PHQ-9) over 5 years and b) patients with persistently high depression symptoms with those who improved (decreased at least 5 points on PHQ-9) over 5 years.
RESULTS: Those who worsened in comparison to those with persistently low depression symptoms did not differ in their pattern of weight change (z = 1.54, p = .12). Both groups weighed approximately 92 kg at baseline and lost approximately 2 kg. A significantly different pattern of change over time was observed for those with persistently high depression symptoms in comparison to those whose depression improved (z = 1.98, p = .04). Although the groups had almost identical weight at baseline (approximately 100 kg), at the 5-year assessment, those with persistently high depression symptoms had about half the weight loss (M = -1.71, SD = 9.08) in comparison to those whose depression improved (M = -3.62, SD = 19.93).
CONCLUSION: In persons with diabetes who have clinically significant levels of depressive symptoms, improvement in depression is accompanied by significantly greater, clinically significant weight loss.