A Review of ONS Prescribing Habits

June 03, 2020 10 min read

Oral nutritional supplements (ONS) are prescribed for patients with disease-related malnutrition who struggle to meet their nutritional requirements through an oral diet alone.1 ONS are used for medical purposes and can be prescribed on the NHS for patients who meet the Advisory Committee on Borderline Substances (ACBS) prescribing criteria, have been screened using a validated malnutrition screening tool and have been deemed to be at nutritional risk. ONS should always be given under medical supervision and must be used appropriately, in accordance with care pathways such as the Malnutrition Pathway.2


Malnutrition in England is estimated to cost £19.6 billion per year; more than 15% of the total public expenditure on health and social care.3 ONS are a clinically and costeffective way to manage disease-related malnutrition,4 but only when they are prescribed appropriately. In 2018/19, the NHS spent £357.9 million on prescribing medical nutrition products (£150.1 million on ONS alone) in primary care.5 BAPEN estimates that appropriate ONS prescribing could save the NHS £101.8 million per year due to reduced use of healthcare resources,3 whilst the National Institute for Health and Care Excellence (NICE) suggests that improving the identification and treatment of malnutrition has the third-highest potential to deliver cost savings to the NHS.6 The NHS Commissioning Guidance on Nutrition and Hydration also recognises that addressing malnutrition has the potential to reduce the impact on the health economy.6

Whilst screening tools do exist, malnutrition still goes undetected and untreated in hospital and community settings. One cross-sectional, mutli-centre study of over 20,000 patients found that less than 50% of patients identified as malnourished in nursing homes, hospitals and home care had received nutritional intervention.7 Nutrition risk screening is vital for ensuring that those who are at risk of malnutrition receive optimum nutritional care and, when indicated, appropriate ONS to support their nutritional and clinical needs, further reducing healthcare burdens and costs.

This article draws on prescribing data gathered by Interface Clinical Services (Interface), a national independent service provider, to provide greater insight into ONS prescribing amongst an adult population. It highlights the need for proactive nutrition risk screening, patient assessment and efficient use of resources and capacity.


The data collection

AYMES International Ltd. (a manufacturer of clinical nutrition products) funded Interface to provide primary care clinical pharmacist support to GP practices in 2019. The pharmacists delivered individual patient reviews to ensure that ONS prescriptions were both clinically appropriate and cost-effective. The protocol direction for these patient reviews was based on NICE guidance, the Malnutrition Pathway, and local prescribing guidance. In addition, Interface pharmacists provided practice and patient education on the topic of ONS prescribing. The reviews were conducted over a 12-month period (04.01.2019–16.12.2019) and involved a registered patient population of 976,350 from 100 GP practices within 49 clinical commissioning groups (CCGs)/trusts/health boards (see Table 1). At the time of writing, this dataset is thought to be the largest of its kind, giving us a unique perspective into ONS prescribing habits and trends.



This section refers to the 4,168 patients reviewed by Interface who had received ONS in the past three months. Based on the data collected by Interface,8 a number of key observations were made, which are summarised in Table 2. The pharmacists also observed that the coded ‘MUST’ scores within the medical records ranged from 0-5 and were recorded over a time period of 2011-2019, despite these patients receiving ONS in the last three months.



The 4,168 patients reviewed were prescribed 4,225 ONS prescriptions (some patients received more than one ONS prescription). A total of 1,526 changes (36%) were made to ONS prescriptions (see Table 3). Changes were made to prescriptions if it was deemed to be of clinical benefit to the patient or in accordance with local guidance, whilst supporting cost efficiencies for the practice and the NHS. A further 83 ONS prescriptions (2%) were stopped altogether, as they were no longer deemed to be clinically appropriate. Further cessation to treatment was actioned by the practice (if appropriate), using a reducing regime initiated by the pharmacist, based on malnutrition pathway guidance.



Firstly, it’s important to reiterate that, when used appropriately, ONS are a clinically and cost-effective treatment of malnutrition. Existing research into the benefits of ONS has shown:

  • Clinical: ONS can reduce clinical complications (e.g. pressure ulcers, poor wound healing, infections) and mortality (in acutely ill older people) and reduce readmissions to hospital 9, 10
  • Dietary: ONS can improve energy and protein intakes, with little reduction in normal food intake9
  • Functional: ONS can help to improve handgrip strength, body weight and quality of life 11
  • Economical: ONS are a clinically and cost-effective way to manage malnutrition, especially in patients with a low body mass index (BMI), living in the community setting.4

This review has highlighted that inappropriate prescribing of ONS and inadequate recording of initiation and monitoring criteria is a major problem in primary care. Whilst the majority of patients in this review were already on ONS that had previously been deemed suitable for their needs, 38% of ONS prescriptions were changed or stopped. Inappropriate ONS prescriptions place additional strains on NHS staff, resources and budgets. NHS England’s medicines optimisation goal to avoid the use of unnecessary medicines highlights the importance of identifying and addressing inappropriate ONS prescriptions. This review found that the cost saving to the NHS generated by stopping or transitioning the reviewed patients onto more appropriate prescriptions was £296,076 per year (see Table 3). These savings could be re-invested through provision of dietetic support in primary care to drive further savings through improved ONS prescribing and patient care.

Furthermore, ‘MUST’ scores were poorly recorded, with only 224 patients (5.4% of the sample population) having a recorded ‘MUST’ score. CQUIN (Commissioning for Quality and Innovation) guidance emphasises the importance of malnutrition risk screening in community and care home settings.12 Part of this process involves accurate and regular recording of ‘MUST’ scores in patient records – this is an important step that is widely recognised in nutrition care pathways, such as the Malnutrition Pathway.2

These findings are supported by further research conducted by Emily Rose, a Lead Dietitian in Primary Care. Her team reviewed 684 ONS prescriptions within two CCGs and found that only 28% of the prescriptions reviewed had a ‘MUST’ score recorded at the time of prescribing.13 It’s important to acknowledge that when auditing a GP patient records system, you will often find a number of patients who are receiving ONS without a recorded ‘MUST’ score. This does not necessarily mean that they have not had a ‘MUST’ score calculated. For example, it may have been documented in care home records but not transferred across to the GP system.

‘MUST’ scores ranged from 0-5, suggesting that some of the lower scores are incorrect (a ‘MUST’ score of 0 indicates a patient is at low risk of malnutrition and is therefore unlikely to require ONS). Interface noted that patients with a ‘MUST’ score of 0 were continuing to receive prescribed ONS. However, this should be interpreted with caution. For example, a GP may have recorded a ‘MUST’ score of 0 due to lack of time or technical glitches as opposed to incorrect calculation. However, as mentioned above, CQUIN and the Malnutrition Pathway make it clear that ‘MUST’ scores should be accurately documented in record keeping systems. Accurate ‘MUST’ scoring and interpretation is essential for making correct prescribing decisions.


Table 1: An Overview of the Review Cohort Conducted by Interface

Criterion Total
Total registered practice population in sites where reviews were completed 976,350
Number of CCGs/trusts/hospital boards in which reviews were delivered 49
Number of GP practices in which reviews were delivered 100
Number of patients reviewed who had received ONS in the past three months 4,168
Criterion Age (years)
The average age of patients reviewed who had received ONS in the past three months 71 (range: 17-106)


Table 2: Reported Observations Based on the Data Collected by Interface

Criterion Number of patients Percentage (%) of sample size (n = 4,168)
Patients with a recorded Malnutrition Universal Screening Tool (‘MUST’) score 224 5.4
Patients who have ever seen a dietitian 1,644 39.4
Patients with a recorded ACBS indication 199 4.8


Table 3: Reported Outcomes Based on the Data Collected by Interface

Criterion Total Percentage (%) of ONS prescriptions (n = 4,225)
Number of changes made to ONS prescriptions 1,526 36
Number of ONS prescriptions stopped 83 2
Criterion Cost (£)
ONS cost of the patient’s pre-review (spend per year) £2,913,168
ONS cost of the patient’s post-review (spend per year) £2,617,092
Total savings to the NHS from the patient’s post-review (spend per year) £296,076


Anecdotally, some doctors admit that they do not know how to calculate a ‘MUST’ score or are unaware of the need to calculate/record it when prescribing ONS. The findings from this review also suggest that doctors may be unaware of the importance of meeting and documenting ACBS prescribing criteria when prescribing ONS. For example, only 199 patients had a recorded ACBS indication, representing just 4.8% of the sample population. In recent years, doctors have been campaigning for further nutrition education. This suggests a greater need for education around ONS prescribing amongst doctors, which could be delivered by registered dietitians working within primary care.

Concerningly, only 1,644 (39.4%) of the patients reviewed had ever seen a dietitian. Establishing whether this is due to poor referral rates or lack of dietetic resources would be useful to understand. According to the Malnutrition Pathway,2 a referral to a dietitian is recommended when patients require ONS as a sole source of nutrition or patients have complex nutritional needs. It also states that if the ONS provides only one or two nutrients (e.g. protein or carbohydrate), they should be used under the supervision of a registered dietitian. Finally, if there is poor patient compliance to ONS, a referral to a dietitian may be appropriate.

NICE guidelines for nutrition support in adults14 state that: ‘Patients should be reviewed according to their progress.’ Whilst PrescQIPP B145 Guidelines for the appropriate prescribing of ONS for adults in primary care15 state that: “Patients prescribed ONS should be reviewed regularly as per recommendations in the ‘MUST’ tool, to assess progress towards their goals and whether there is a continued need for ONS on an NHS prescription. This review should be carried out by a suitable person.” They also recognise that: “Many patients with chronic disease experience diet related issues that may benefit from dietetic review not only to treat malnutrition but to advise on the dietary modifications to manage the disease or condition.”

Dietitians are well-placed to provide patients with dietary counselling in a primary care setting, drawing on food-first approaches where possible. Research by Baldwin and Weekes has highlighted how dietary counselling with or without ONS is effective at increasing nutritional intake and weight.16 The recently updated GP Contract (2020/2021 - 2023/24) emphasises the importance of giving Primary Care Networks (PCNs) increasing flexibility to recruit additional staff (including allied healthcare professionals) to meet additional demands on GP practices.17 Under this new contract, PCNs will be able to access funding to support recruitment, with an overarching goal of securing 26,000 extra healthcare staff, including:

  • Pharmacy technicians
  • Health and wellbeing coaches and care coordinators
  • Occupational therapists
  • DietitiansPodiatrists
  • Podiatrists
  • Community paramedics

However, the role of a dietitian extends further than dietary counselling and appropriate prescribing of ONS. A landmark decision by NHS England in 2016 meant that dietitians would, for the first time ever, be given supplementary prescribing responsibilities following successful completion of a Health and Care Professions Council (HCPC) approved prescribing programme.18 The dietetic prescribing debate is somewhat complex and has recently been considered within the British Dietetic Association (BDA) document ‘Nutritional Borderline Substances – Case for Change’.19



In conclusion, this review has highlighted how appropriate ONS prescribing has the potential to make significant cost savings to the NHS, which supports NHS England’s medicines optimisation goal. When used appropriately, ONS remains a clinically and cost-effective way to manage long-term conditions requiring nutrition support and disease-related malnutrition. However, this review has also shown that ONS is only effective if patients are reviewed and monitored by a healthcare professional to assess whether there is a continued need, and whether treatment choices are aligned to that changing need. It has also identified that there is a need for further education around ONS prescribing amongst doctors, especially those in primary care. Dietitians are wellplaced to review patients and can deliver this training as they are the only qualified healthcare professionals who are able to assess, diagnose and treat dietary and nutrition related problems. Encouragingly, the importance of dietetics within primary care is becoming increasingly recognised, as evidenced by the newly updated GP contract. The BDA also offers an online e-learning module entitled ‘Appropriate Prescribing for Dietitians’ to support CPD by improving awareness and competencies within the profession. The profession can play a key role in helping to reduce NHS expenditure whilst continuing to deliver excellent standards of nutritional care to patients. This review has shown how optimising ONS prescriptions can free-up significant budget, saving the NHS hundreds of thousands of pounds per year. These cost savings to the NHS could be used to recruit more dietitians to work on the frontline within primary care settings, whilst improving patient outcomes and reinforcing the clinical value of the appropriate use of ONS products.





1. Gandy J [Ed.] (2014). Manual of Dietetic Practice, chp. 6.3 Oral Nutritional Support. Wiley-Blackwell on behalf of the BDA.

2. Malnutrition Pathway (2017). Managing Malnutrition: Including a Pathway for Appropriate Use of ONS. Accessed online: www.malnutritionpathway.co.uk/library/managing_malnutrition.pdf (Apr 2020).

3. Elia M (2015). The cost of malnutrition in England and potential cost savings from nutritional interventions (short version). Accessed online: www.bapen.org.uk/pdfs/economic-report-short.pdf (Apr 2020).

4. Elia M, et al. (2016). A systematic review of the cost and cost effectiveness of using standard oral nutritional supplements in community and care home settings. Clin Nutr.; 35(1): 125-137.

5. NHS Business Services Authority (2020). Prescribing Data. Accessed online: www.nhsbsa.nhs.uk/prescription-data/prescribing-data (Apr 2020)

6. NHS England (2015). Guidance - Commissioning Excellent Nutrition and Hydration: 2015-2018 Accessed online: www.england.nhs.uk/wp-content/uploads/2015/10/nut-hyd-guid.pdf (Apr 2020).

7. Meijers JM, et al. (2009). Malnutrition in Dutch health care: Prevalence, prevention, treatment, and quality indicators. Nutrition; 25(5): 512-519

8. Data on file (2020). Interface Clinical Services.

9. Cawood AL, et al. (2012). Systematic review and meta-analysis of the effects of high-protein oral nutritional supplements. Ageing Res Rev.; 11(2): 278-296.

10. Stratton RJ, Elia M. (2007). A review of reviews: A new look at the evidence for oral nutritional supplements in clinical practice. Clinical Nutrition Supplements;2, 5-23. Clin Nutr Suppl.; 2(1): 5-23.

11. Norman K et al. (2008). Three month intervention with protein and energy rich supplements improve muscle function and quality of life in malnourished patients with non-neoplastic gastrointestinal disease- a randomized controlled trial. Clin Nutr.; 27(1): 48-56.

12. NHS (2020). Commissioning for Quality and Innovation (CQUIN). Guidance for 2020- 2021.Accessed online: www.england.nhs.uk/wp-content/uploads/2020/01/FINAL-CQUIN-20-21-Core-Guidance-190220.pdf (Apr 2020).

13. Rose E (2020). A dietitian-lead medicines management team model of practice to address inappropriate oral nutritional supplement prescribing in primary care. Clin Nutr ESPEN.; 35: 240-241.

14. NICE (2006). Nutrition support for adults: oral nutrition support, enteral tube feeding and parenteral nutrition. Clinical guideline [CG32]. Accessed online: www.nice.org.uk/guidance/cg32 (Apr 2020).

15. PresQUIPP (2017). Guidelines for the appropriate prescribing of oral nutritional supplements (ONS) for adults in primary care. Accessed online: www.prescqipp.info/media/1512/b145-ons-guidelines-30.pdf (Apr 2020).

16. Baldwin C, Weekes CE (2011). Dietary advice with or without oral nutritional supplements for disease related malnutrition in adults. Cochrane Database Syst Rev.; 2011(9): CD002008.

17. British Medical Association (BMA) (2020). GP Contract Agreement England 2020/21. Accessed online: https://archive.bma.org.uk/collective-voice/committees/ general-practitioners-committee/gpc-england/gp-contract-agreement-england-2020-2021 (Apr 2020).

18. NHS (2016). Supplementary prescribing by Dietitians. Accessed online: www.england.nhs.uk/ahp/med-project/ dietitians/ (Apr 2020).

19. BDA (2017). Nutritional Borderline Substances - Case for Change. Accessed online: www.bda.uk.com/uploads/assets/c09ad84d-bea1-4546-bc67e49570b29a3d/nbscaseforchange.pdf (Apr 2020).