Protein and energy supplementation in elderly people at risk from malnutrition

This review was carried out because evidence for the effectiveness of nutritional supplements containing protein and energy which are often prescribed for elderly people is limited. Furthermore malnutrition is more common in this age group and deterioration of nutritional status can occur during a stay in hospital. It is important to establish whether supplementing the diet with protein and energy is an effective way of improving outcomes for older people at risk from malnutrition.

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

We searched The Cochrane Library (issue 1, 2001), MEDLINE (1966 to February 2001), EMBASE (1980 to March 2001), Health star (1975 to March 2001), CINAHL (1982 to Jan 2001), BIOSIS (1985 to March 2001) and CAB abstracts (1973 to March 2001). We also hand searched nutrition journals and reference lists and contacted 'sip-feed' manufacturers. Date of most recent search: March 2001.

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.

Two reviewers independently assessed trials prior to inclusion and independently extracted data and assessed trial quality; any differences were resolved by reaching consensus. Authors of trials were contacted for further information as necessary.

Thirty-one trials with 2464 randomised participants have been included in the review. Most included trials had poor study quality. Mortality data were combined for meta-analysis from twenty-two trials (1755 participants). The Relative Risk (RR) indicated a lower mortality in the supplemented group compared with the control group (0.67; 95% confidence interval (CI) 0.52 to 0.87). The risk of complications (total complications if available, otherwise for example the number of infections by the end of follow-up) from nine trials (608 participants) showed no significant difference (RR 0.93, 95% CI 0.77 to 1.13). We were unable to combine trials for meta-analyses of functional outcome, for example grip strength, walking distance and Barthel Index, however there was little evidence of benefit to functional outcomes from individual studies. Data describing length of stay were available from seven trials (658 participants). There was some indication that mean length of stay was shorter for the supplemented groups (-3.4 days, 95% CI -6.12 to -0.69).

Supplementation appears to produce a small but consistent weight gain. There was a statistically significant beneficial effect on mortality and a shorter length of hospital stay. Additional data from large-scale multi-centre trials are still required to provide clear evidence of benefit from protein and energy supplements on mortality and length of hospital stay. Too few data were reported and the time scale of most studies was too short to have a realistic chance of detecting differences in morbidity, functional status and quality of life. Furthermore, most trials do not address the organisational and practical challenges faced by practitioners trying to meet the individual needs and preferences of those at risk from malnutrition.