Lifestyle Intervention for People With Severe Obesity and Serious Mental Illness

Abstract

Introduction: People with serious mental illness experience elevated severe obesity rates, yet limited evidence documents whether lifestyle intervention participation can benefit these individuals. This study examined the impact of the In SHAPE lifestyle intervention on weight loss among participants with serious mental illness and severe obesity (BMI ≥40) compared with participants who are overweight (BMI 25 to <30) and have class I (BMI 30 to <35) or class II (BMI 35 to <40) obesity.

Methods: Data were combined from three trials of the 12-month In SHAPE intervention for individuals with serious mental illness collected between 2007 and 2013 and analyzed in 2014. In SHAPE includes individual weekly meetings with a fitness trainer, a gym membership, and nutrition education. The primary outcome was weight loss. Secondary outcomes were fitness, blood pressure, lipids, and program adherence.

Results: Participants (N=192) were diagnosed with schizophrenia spectrum (53.1%) or mood (46.9%) disorders. At 12 months, the overall sample showed significant weight loss, but differences among BMI groups were not significant (severe obesity, 2.57% [7.98%]; class II, 2.26% [8.69%]; class I, 1.05% [6.86%]; overweight, 0.83% [7.62%]). One third of participants with severe obesity achieved ≥5% weight loss, which was comparable across groups. More participants with severe obesity achieved ≥10% weight loss (20%) than overweight (2.9%, p=0.001) and class I (5.9%, p<0.001), but not class II (17.8%, p=0.974), obesity groups.

Conclusions: People with severe obesity and serious mental illness benefit similarly to those in lower BMI groups from lifestyle intervention participation.

Figure 1

Clinically significant changes in weight and fitness compared between BMI groupsa, b ^a Overweight: BMI 25 to <30 kg/m²; Class I obesity: BMI 30 to <35 kg/m²; Class II obesity: BMI 35 to <40 kg/m²; and Severe Obesity: BMI ≥ 40 kg/m^{2 b} The proportion of participants who achieved improved fitness determined as >50 meter and >80 meter increase on the 6-Minute Walk Test did not differ significantly between BMI groups. * Participants with class I obesity were significantly less likely to achieve ≥5% weight loss compared to participants with severe obesity (OR=0.57; 95% CI=0.37–0.90). ** Participants who were overweight were significantly less likely to achieve ≥10% weight loss compared to participants with severe obesity (OR=0.21; 95% CI=0.08–0.52). *** Participants with class I obesity were significantly less likely to achieve ≥10% weight loss compared to participants with severe obesity (OR=0.26; 95% CI=0.13–0.55).