Effectiveness of a nurse-led phone intervention on body composition in adults with prediabetes and overweight/obesity: PREDIPHONE secondary analysis

Background Prediabetes and obesity are strongly linked to metabolic risk, with visceral adipose tissue playing a central role. Lifestyle interventions combining physical activity and healthy diet are effective for body composition improvement, but most are resource-intensive. Evidence on low-intensity, scalable approaches delivered by primary care professionals, such as nurse-led telephone interventions, remains limited. This secondary analysis of the PREDIPHONE randomized controlled trial assessed the effectiveness of a low-intensity nurse-led telephone lifestyle intervention on body composition outcomes at 4 months (mid-intervention), 9 months (end of intervention), and 15 months (6 months post-intervention). Methods The analysis included 174 participants with available body composition data originally enrolled in the PREDIPHONE trial. Original group allocation was retained. Body composition parameters (fat mass, muscle mass, and visceral adipose tissue) were measured using bioelectrical impedance analysis at each time point. Physical activity and adherence to the Mediterranean diet were assessed using validated questionnaires. Group differences were evaluated using general linear models adjusted for baseline values, age, and sex. Results Participants had a mean age of 61.1 years, and 52.3% were women. Compared with the active SMS-based control group, the intervention group achieved short-term reductions in visceral adipose tissue and fat mass at 4 months. These changes were not maintained at 9 or 15 months. No significant differences were observed in muscle mass or body mass index. Conclusion In this population, a low-intensity, nurse-led telephone intervention produced modest short-term improvements in body composition without sustained effects. More intensive or prolonged strategies may be required to produce clinically meaningful and sustainable changes in primary care settings. Trial registration Clinicaltrials.gov , identifier NCT04735640.