The effectiveness of a targeted education intervention to increase protein intake in people with coronary heart disease: A pilot feasibility randomised controlled trial

Low protein intake is prevalent in people with coronary heart disease (CHD) and is inadequately addressed in UK-based cardiac rehabilitation (CR). This pilot feasibility study aimed to identify whether targeted education increases protein intake in patients with CHD and low protein intake, compared with standard CR dietary education. People referred to CR with CHD (≥50 years) underwent anthropometric assessment, and completed a food diary, sit-to-stand test and three questionnaires (physical activity, sarcopenia screening, and nutrition knowledge). Participants with low protein intake (≤1.2 g/kg/day) were randomised to receive either extra protein education (intervention; PG) or standard education (control; CG), embedded within their usual six-week CR programme. At 6- and 12-weeks, outcome measures were repeated; 34 participants provided baseline data. Protein intake was inversely associated with waist circumference (r = ˗0.348). Twenty-seven participants (79%) with low protein intake were randomised to PG (n = 15) or CG (n = 12). At Week 6, the median (interquartile range) change in protein intake was 0.0 (˗0.0, 0.3) and 0.4 (0.2, 0.5) g/kg/day in PG and CG, respectively (effect size 0.5). At Week 12, the change in protein intake was 0.0 (˗0.0, 0.1) and ˗0.0 (˗0.2, 0.2) g/kg/day in PG and CG, respectively (effect size 0.3). Effect sizes for all other variables were ≤0.4. The intervention appeared well-received by those who completed the study; however, changes to primary and secondary outcomes were minimal. Uptake to the study was low and attrition high, limiting the interpretation of efficacy and the implementation of a definitive trial.