Protein and energy supplementation in elderly people at risk from malnutrition

Abstract

Background: Evidence for the effectiveness of nutritional supplements containing protein and energy, which are often prescribed for older people, is limited. Furthermore malnutrition is more common in this age group and deterioration of nutritional status can occur during illness. It is important to establish whether supplementing the diet is an effective way of improving outcomes for older people at risk from malnutrition.

Objectives: This review examined the evidence from trials for improvement in nutritional status and clinical outcomes when extra protein and energy were provided, usually in the form of commercial 'sip-feeds'.

Search strategy: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, Healthstar, CINAHL, BIOSIS, CAB abstracts. We also hand searched nutrition journals and reference lists and contacted 'sip-feed' manufacturers. Date of most recent search: March 2004.

Selection criteria: Randomised controlled trials and quasi-randomised controlled trials of oral protein and energy supplementation in older people with the exception of groups recovering from cancer treatment or in critical care.

Data collection and analysis: Two reviewers independently assessed trials prior to inclusion and independently extracted data and assessed trial quality. Authors of trials were contacted for further information as necessary.

Main results: Forty-nine trials with 4790 randomised participants have been included in the review. Most included trials had poor study quality. The pooled weighted mean difference [WMD] for percentage weight change showed a benefit of supplementation of 2.3% (95% confidence interval (CI) 1.9 to 2.7) from 34 trials. There was a reduced mortality in the supplemented compared with control groups (relative risk (RR) 0.74, CI 0.59 to 0.92) from 32 trials. The risk of complications from 14 trials showed no significant difference (RR 0.95, 95% CI 0.81 to 1.11). Few trials were able to suggest any functional benefit from supplementation. The pooled weighted mean difference (WMD) for length of stay from 10 trials also showed no statistically significant effect (WMD -1.98 days, 95% CI -5.20 to 1.24).

Authors' conclusions: Supplementation produces a small but consistent weight gain in older people. There may also be a beneficial effect on mortality. However, there was no evidence of improvement in clinical outcome, functional benefit or reduction in length of hospital stay with supplements. Additional data from large-scale multi-centre trials are still required.