Nutrition screening is the first step to identify people who may be at nutritional risk. This includes identifying people who are underweight, overweight or at risk of malnutrition.
Nutritional risk can be influenced by many things including:
- Low appetite
- COVID-19 symptoms affecting eating
- Comorbidities affecting eating, digestion, absorption or utilisation of nutrients
- Food insecurity
- Social and economic factors
Who can screen?
All health and social care professionals can support the task of nutrition screening.
Early interventions are essential to improve outcomes and this includes recognising when referral to a dietitian and/or support from community services is needed.
Screening can be carried out by any person working in health or social care who has been appropriately trained. Patients, clients and carers can also self-screen.
Benefits of nutrition screening
Nutrition screening facilitates early nutritional intervention by helping healthcare professionals and carers recognise when nutritional treatment is needed. This may include a referral to a dietitian or support from community services (Donnelly and Keller, 2021).
Screening programmes for identifying nutritional risk should be considered part of support for people recovering from COVID-19. In particular they should be used to identify vulnerable or older patients needing nutritional treatment or support. If nutritional interventions are inadequate, patients whose health is already compromised might experience worse clinical outcomes (Ferrara, De Rosa and Vitiello, 2020). People at risk of poor nutrition (malnutrition) are also likely to need to access more healthcare support and treatments.
Guidelines state that support for COVID-19 recovery should be available regardless of whether a positive COVID-19 test was obtained, since neither PCR testing nor antibody tests have adequately captured all disease (Brika et al., 2020; Ochoa et al., 2020).
Screening tools
Malnutrition risk
There are many screening tools available. Your own organisation is likely to recommend a screening tool to use. Screening tools are often embedded in electronic patient records. The most commonly used nutrition screening tool to identify malnutrition risk in the NHS is the Malnutrition Universal Screening Tool [PDF], with an online calculator also available (Zhao et al., 2023).
Self-screening is possible when patients or their carers have the capacity to use a tool to identify their own risk. For example the online self-screening Malnutrition Universal Screening Tool has been validated for use by patients (Cawood et al., 2018). Having patients self-screen has advantages including the scope to screen large numbers of people and supporting patients to self-monitor nutritional risk at home. Self-screening is particularly useful when infection control measures are needed.
The Patients Association Nutrition Checklist can be helpful to begin conversations around nutritional risk. It is not a screening tool, but does help identify concerns and provides suggested actions to help manage some of the nutritional concerns.
Those who are overweight or living with obesity
These patients are also at malnutrition risk. This is why identifying those who are overweight or living with obesity is also important to ensure timely support and advice is provided. The NHS provides information on both identification and support.
Obesity can be identified by assessing:
Body mass index (BMI)
According to the NHS website the following ranges should be used:
- 25 to 29.9 kg/m2 – overweight range
- 30 to 39.9 kg/m2 – obesity
- 40 kg/m2 or above – severe obesity
Asian, Chinese, Middle Eastern, Black African or African-Caribbean family background require a lower BMI score to measure overweight and obesity: 23 to 27.4 – overweight range; 27.5 or above – obesity.
This BMI measure is not advised for those under 18 years of age, in pregnant people, for those with an eating disorder or in conditions which affect height.
Waist to height ratio
- This is useful for those with a BMI under 35kg/m2
- The NHS website provides information on how to assess weight-to-height ratio with a waist-to-height ratio of 0.5 or higher suggesting increased health risks due to obesity.
Waist circumference
People with metabolic diseases are known to be at a greater risk of more severe COVID-19. Identifying the risk of these diseases is therefore important. Central adiposity (abdominal fat) is known to increase the risk of metabolic disease, in particular cardiovascular disease (Jayedi et al., 2020). It also increases the risk of diabetes.
A consensus statement on waist circumference from the International Atherosclerosis Society and the International Chair on Cardiometabolic Risk Working Group on Visceral Obesity states that BMI and waist circumference together can improve assessment of cardiometabolic risk compared with either measurement alone.
It is also useful when weighing a patient is not possible, with guidance provided by the NHS on how to measure waist circumference [PDF].
This NHS video explains how to measure waist circumference.
Waist circumference reference ranges are suggested as:
- Healthy weight (BMI 18.5-24.9kg/m2) Women: > 80cm Men: > 90cm
- Overweight (BMI 25 - 29.9 kg/m2) Women: > 90cm Men: > 100cm
- Obese I (BMI 30 - 34.9kg/m2) Women: > 105cm Men: > 110cm
- Obese II and III (BMI >35 kg/m2) Women: > 115cm Men: > 125cm
Clinical judgement
Screening tools are a guide and do not replace clinical judgement which should consider:
- Relevant, recent measurements of the individual’s body
- Symptoms or clinical condition
- Food accessibility
- Assessment of living situation, for example, do patients have appropriate support for their nutritional care?
- Use of prescribed nutritional supplements or other specific dietary-related products
Regardless of nutritional risk, people who have concerns about their nutrition may also need access to advice (Barazzoni et al., 2020).
Patients in post-COVID-19 clinics will need screening when either the patient or healthcare professional is concerned. See our Managing patients symptoms linked to nutrition during COVID-19 recovery page in our symptom toolkit.
Next steps after screening
Once you have identified risk of malnutrition, an appropriate nutrition care plan should be provided and documented. This may include referral for specialist dietetic input (Cawood et al., 2020). Go to our Assessing patients' nutritional needs and setting realistic goals during COVID-19 recovery page for advice on how to do this.
Since telehealth has been established and become widely used, dietitians have been able to treat at-risk patients within hospital, primary care and community settings. For patients who require referral for expert nutritional advice, make sure you distinguish between existing long-term conditions and COVID-19 related complications (NHS, 2020).