(P20-013-25) Protein and Resistance Exercise to Stop Sarcopenic Obesity Now (PRESS ON) Pilot & Feasibility Trial

Objectives: Weight loss improves cardiometabolic health, but skeletal muscle loss may cause sarcopenia in at-risk adults. This pilot Sequential Multiple Assignment Randomized Trial (SMART) aimed to assess the feasibility of a future full-scale SMART to test dynamic intensive behavioral therapy (IBT) regimens for obesity in aging adults. Study retention, engagement, and intervention credibility/expectancy are reported here.

Methods: Eighty-three adults (50-75y, BMI 30-50 kg/m²) participated in group-based IBT for 16 weeks and were randomized to follow a high-protein diet (HP) or engage in self-directed resistance training (RT). At week 8, participants achieving either < 5.5% fat mass loss or >1.5% fat free mass (FFM) loss were re-randomized to IBT augmentation strategies comprising daily protein supplements and/or supervised RT. Participants completed the Treatment Credibility and Expectancy Questionnaire before randomization. Class attendance, study retention, and changes in blood urea nitrogen (BUN, HP adherence) and grip strength (RT adherence) were measured at week 16.

Results: Study retention was 90.4% and participants attended 86.8% of group IBT sessions. Among study completers, pooled weight loss was 9.5±5.3%, 90.7% achieved ≥5% weight loss, and ≤20% of weight was lost as FFM. The non-response rate to fist-line IBT strategies was 80.4%, primarily due to losing >1.5% of FFM. By week 8, BUN increased 3.5±4.2 mg/dl in HP vs. +2.0±4.2 mg/dl in RT, and grip strength increased 4.3±7.6 lbs. in RT vs. +5.5±6.7 lbs. in HP. At baseline, participants reported interventions as being highly credible ( >7/9 for all) and they expected to achieve their weight loss (6.6-6.9/9) and muscle preservation goals (6.0-6.7/9).

Conclusions: Study retention, IBT attendance, and pooled weight loss met a priori feasibility thresholds, and the interventions were perceived as being highly credible. The non-response rate to initial IBT strategies was higher than expected (80.4% vs. 67%), which will require modification prior to a full-scale SMART. A lower improvement in grip strength among RT participants suggest that self-directed RT may not be a feasible first-line IBT strategy for FFM retention during weight loss in this population and should be modified for a full-scale SMART.

Funding Sources: NIDDK and the Nutrition Obesity Research Center, University of Alabama at Birmingham