Oral nutritional interventions in frail older people who are malnourished or at risk of malnutrition: a systematic review

Background: Malnutrition worsens the health of frail older adults. Current treatments for malnutrition may include prescribed oral nutritional supplements, which are multinutrient products containing macronutrients and micronutrients. Objective: To assess the effectiveness and cost-effectiveness of oral nutritional supplements (with or without other dietary interventions) in frail older people who are malnourished or at risk of malnutrition. Data sources: MEDLINE, EMBASE, Cochrane Library, Scopus, CINAHL (Cumulative Index to Nursing and Allied Health Literature) and grey literature were searched from inception to 13 September 2021. Review methods: A systematic review and meta-analysis was conducted to evaluate the effectiveness and cost-effectiveness of oral nutritional supplements in frail older people (aged >= 65 years) who are malnourished or at risk of malnutrition (defined as undernutrition as per National Institute for Health and Care Excellence guidelines). Meta-analysis and network meta-analysis were undertaken, where feasible, along with a narrative synthesis. A cost-effectiveness review was reported narratively. A de novo model was developed using effectiveness evidence identified in the systematic review to estimate the cost-effectiveness of oral nutritional supplements. Results: Eleven studies (n = 822 participants) were included in the effectiveness review, six of which were fully or partly funded by industry. Meta-analyses suggested positive effects of oral nutritional supplements compared with standard care for energy intake (kcal) (standardised mean difference 1.02, 95% confidence interval 0.15 to 1.88; very low quality evidence) and poor mobility (mean difference 0.03, p < 0.00001, 95% confidence interval 0.02 to 0.04; very low quality evidence) but no evidence of an effect for body weight (mean difference 1.31, 95% confidence interval -0.05 to 2.66; very low quality evidence) and body mass index (mean difference 0.54, 95% confidence interval -0.03 to 1.11; very low quality evidence). Pooled results for other outcomes were statistically non-significant.