Methods. The trial was conducted in three supportive housing agencies, enrolled 314 participants randomly assigned to PGLB or usual care (UC). PGLB is a 12-month manualized healthy lifestyle intervention delivered by peer-specialists. Assessment were conducted at baseline, 6, 12, and 18 months post-randomization. Study outcomes examined for the total sample and by study site were proportion of participants that achieve clinically significant changes from baseline on: weight loss (>5% weight loss), cardiorespiratory fitness (CRF, >50 meters increase in the 6-minutes walking test [6MWT]) and cardiovascular (CVD) risk reduction (clinically significant weight loss or CRF improvement). An intent-to-treat approach was used for all analyses. Logistic regression models were used to compare the effectiveness of PGLB versus UC on our three dichotomous outcomes at 6, 12, and 18 months for the total sample and stratified by study site.
Results. Participants were mostly racial/ethnic minorities (81.7%), mostly non-Hispanic blacks, with a mean baseline weight of 218.8 (SD=54lbs) and mean BMI of 33.7 (SD=7.2). The most common psychiatric diagnoses at baseline were major depression (75.9%), schizophrenia/schizoaffective disorder (57.2%), and anxiety disorders (50.6%). On average, participants reported 3.7, (SD=2.4) medical illnesses, most commonly hypertension (55.8%), high cholesterol (37%) and diabetes mellitus (32.7%). Although a larger proportion of PGLB participants than UC achieved clinically significant changes in weight loss, CRF and CVD risk reductions at 12 and 18 months, none were statistically significant. Outcomes differed by study site with two sites reporting no significant differences between PGLB and UC, and one site reporting that PGLB significantly outperformed UC on clinically significant weight loss at 18 months (PGLB=41.7% vs. UC=21.7%, Adjusted Odds Ratio [AOR]=2.57, 95% CI [1.02, 6.49]) and clinically significant reductions in CVD risk at 6 months (PGLB=47.5 vs. UC=26.7, AOR=2.51 95% CI [1.07, 5.90]), and 12 months (PGLB=59.3% vs. UC=32.7%, AOR=2.99 95% CI [1.33, 6.72]).
Conclusions & Implications. PGLB was not superior than UC in achieving clinically significant changes in weight loss, increases in CRF, and reductions in CVD risk. Although our findings suggest that some racially/ethnically diverse people with SMI who are overweight/obese and in supportive housing could benefit from a peer-led healthy lifestyle intervention, multiple questions remain about how this intervention work, for whom, and under which conditions it exert its biggest impacts. More studies are needed to clarify why PGLB works in certain settings and not others.