What are the benefits and risks of different types of nutritional support for older, hospitalised people who are malnourished or at risk of malnutrition?

Key messages

• Compared to standard hospital care, specialised foods and drinks may reduce the chances of dying and of having a serious negative health event one month after hospital admission.

• In terms of people's ability to perform basic daily activities, their quality of life, length of hospital stay, and body weight, we are either very uncertain about the benefits and risks of the different types of nutritional support, or evidence shows they may make little or no difference compared to standard hospital care.

• Larger and well-designed studies comparing different types of nutritional support may increase our confidence in these findings.

What is malnutrition?

People become malnourished when their intake of energy and protein is not enough to meet their body's needs. This condition can reduce someone's fat and muscle stores. Being malnourished threatens people's health and compromises the immune system's ability to fight infections. Older people who are malnourished are at higher risk of disease complications, losing their independence, and dying than non-malnourished older people. They also experience a lower quality of life.

Older people may become malnourished or be at risk of malnutrition for several reasons, including having a reduced appetite, chewing problems, physical limitations (e.g. unable to stand for long periods to prepare meals), and loneliness.

Older people in hospital are particularly prone to malnutrition. They may not eat enough at a time when their illness increases their energy and protein needs. Malnutrition affects roughly one-third to two-thirds of hospitalised older people.

How is malnutrition treated?

There is a wide range of treatments for malnutrition, including: specialised foods and beverages that provide extra energy, protein, and other nutrients; practical help with eating and drinking; additional snacks, protein-rich foods or supplements; nutritional counselling; or tailored combinations of these approaches.

What did we want to find out?

In older, hospitalised people who are malnourished or at risk of malnutrition, we wanted to know if different types of nutritional support are better than standard care at:

• reducing the risk of dying and serious negative health events (e.g. complications such as infections or wound healing);

• improving people's ability to perform basic daily activities and their quality of life;

• reducing time spent in hospital; and

• boosting people's body weight and muscle mass.

We also wanted to know which type of nutritional support works best.

What did we do?

We searched for studies in people 65 years and older who were in hospital and malnourished or at risk of malnutrition. We included studies that compared one type of nutritional support to another type, or compared nutritional support to standard hospital care (i.e. usual hospital food service), sometimes in combination with a 'dummy treatment' that looked identical to the supplements tested. We summarised and compared all treatments, and rated our confidence in the results based on factors such as study methods and the numbers of people included.

What did we find?

We found 21 studies involving 3309 hospitalised older people with different acute conditions. We grouped the treatments they received into five categories:

• specialised foods and drinks;

• protein-enriched foods or supplements;

• energy supplements;

• personalised feeding support from an assistant (who would, for example, accommodate food preferences, adjust someone's position, and help with eating);

• multi-component personalised nutritional care from a dietitian or nutritionist (who would, for example, modify foods or offer counselling).

Main findings

Compared to standard hospital care, after a month in hospital, specialised foods and drinks may:

• reduce the chance of death: they may lead to 57 fewer deaths per 1000 people;

• reduce serious negative health events: they may lead to 84 fewer events per 1000 people.

Compared to standard hospital care, we are either very uncertain about the effects of specialised foods and drinks, protein-enriched foods or supplements, energy supplements, personalised feeding support, and multi-component personalised nutritional care, or these treatments may make little or no difference to people's:

• ability to perform basic daily activities;

• quality of life;

• length of hospital stay;

• body weight and muscle mass.

When we compared the different types of nutritional support to each other, we did not find that any one approach worked better than all others in improving the results we measured.

What are the limitations of the evidence?

Our confidence in the findings is low or very low for several reasons. Some studies used methods that may have led to errors in the results. Studies often involved too few people, or did not look at everything we were interested in, such as muscle mass as outcome or comparisons of different types of nutritional support. Moreover, older people in hospital have different illnesses and functional abilities, and we could not assess how the different types of nutritional support work for different people.

How current is this evidence?

The evidence is current to 2 July 2024.