Does mental health influence weight loss in adults with prediabetes? Findings from the VA Diabetes Prevention Program

Objectives: Mental illness may impact outcomes from structured behavioral weight loss interventions. This secondary analysis investigated the influence of mental health on weight loss among Veterans with prediabetes enrolled in either an in-person diabetes prevention program (DPP) or the usual care weight management program (MOVE!) designed to help patients achieve weight loss through changes in physical activity and diet.

Methods: Prediabetes was defined by Hemoglobin A1c between 5.7 and 6.4% or Fasting Plasma Glucose 100-125 mg/dL and no use of antiglycemic medications during the past six months. Veterans Health Administrative data were used to assign Veterans into one of three mental health diagnoses: severe mental illness (SMI), affective disorder (AD) without SMI, or No SMI/No AD. The influence of mental health on weight changes at 6 and 12 months was modeled using linear mixed-effects regression.

Results: On average, Veterans with prediabetes (n = 386) were 59 years old (SD = 10.0 years), with a BMI of 34.8 kg/m² (SD = 5.3 kg/m²) and A1c of 6.0% (SD = 0.2%). The sample consisted of 12% (n = 47), 39% (n = 150), and 49% (n = 189) diagnosed with SMI, AD and No SMI/No AD, respectively. Across interventions, Veterans with SMI lost less weight than those with AD or No SMI/No AD. From baseline to 6 months, weight loss was significantly less for Veterans with SMI (1.53 kg) compared to Veterans with AD (3.85 kg) or No SMI/No AD (3.73 kg). This weight loss trend by mental health diagnosis continued from baseline to 12 months but was no longer statistically significant at 12 months.

Conclusion: Weight loss was not clinically or statistically different among Veterans with prediabetes diagnosed with AD or No SMI/No AD. However, Veterans diagnosed with SMI exhibited less weight loss over 6 months than Veterans with AD or No SMI/No AD and though not statistically significant, the trend continued to 12 months, suggesting that SMI may influence weight loss outcomes.