Eleven studies were included in the review (1,012 patients, range 12 to 345 per study). These included four randomised controlled trials (RCTs), three case series, two non-randomised controlled studies, one quasi-experimental study and one historical control study. Study quality ratings were positive (five studies, including three RCTs) or neutral (six studies).
Compared with standard meals, energy dense meals were associated with statistically significantly greater intakes of energy (WMD 324 kcal/day, 95% CI 212 to 436) and protein (WMD 9.1 grams/day, 95% CI 0.2 to 17.9). These findings came from one case series, one crossover RCT and one non-RCT; heterogeneity was low for energy intake (Ι²=39%) and high for protein intake (Ι²=89%).
In evaluations of oral nutritional supplements (plus meals) (two RCTs, one case series), energy intake, protein intake, weight and albumin levels increased in all intervention groups. Statistically significant differences between intervention groups and control groups (usual meals only) were only consistently shown for energy intake and protein intake (no meta-analyses performed). Results were mixed for changes in mid arm circumference and triceps skin fold. In comparisons of specialty versus standard oral nutritional supplements (plus meals) (two RCTs, one non-RCT), increases in energy intake and weight were greater with the use of specialty oral nutritional supplement but these between-group differences were not statistically significant. Mixed results were shown for protein intake, and changes in albumin and pre-albumin levels.
Further results (including results for secondary outcomes and/or results only reported by singular studies) were reported in the review paper.