Malnutrition: Causes and Consequences Increased Losses Or Altered Requirements

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CME Nutrition Clinical Medicine 2010, Vol 10, No 6: 624–7

Malnutrition: causes and consequences Increased losses or altered requirements

In some circumstances, such as enterocuta- John Saunders, specialist registrar in 28% of inpatients were at risk of malnu- neous fistulae or burns, patients may have clinical nutrition and gastroenterology; trition. The prevalence was higher in spe- excessive and/or specific nutrient losses; Trevor Smith, consultant in clinical cific subpopulations: for example, 34% their nutritional requirements are usually nutrition and gastroenterology of all emergency admissions and 52% of very different from normal metabolism. admissions from care homes.4 Specific micronutrient deficiencies are Institute of Human Nutrition, Southampton Energy expenditure University Hospitals, Southampton also common, especially in the elderly: for example, folate deficiency has been It was thought for many years that described in 29% of the independent increased energy expenditure was pre- The term ‘malnutrition’ has no univer- elderly population and 35% of those in dominantly responsible for disease- sally accepted definition. It has been used institutional care.5 related malnutrition. There is now clear to describe a deficiency, excess or imbal- evidence that in many disease states total ance of a wide range of nutrients, energy expenditure is actually less than resulting in a measurable adverse effect Causes of malnutrition in normal health. The basal hypermetab- on body composition, function and clin- Malnutrition in developed countries is olism of disease is offset by a reduction in ical outcome.1 Although malnourished unfortunately still more common in sit- physical activity, with studies in intensive individuals can be under- or overnour- uations of poverty, social isolation and care patients demonstrating that energy ished, ‘malnutrition’ is often used syn- substance misuse. However, most adult expenditure is usually below 2,000 onymously with ‘undernutrition’, as in malnutrition is associated with disease kcal/day. The exception is patients with this article. and may arise due to: major trauma, head injury or burns where energy expenditure may be con- reduced dietary intake The size of the problem • siderably higher, although only for a reduced absorption of macro- and/ • short period of time.8,9 Malnutrition is a common, under-recog- or micronutrients nised and undertreated problem facing increased losses or altered requirements • Consequences of malnutrition patients and clinicians. It is both a cause • increased energy expenditure (in and consequence of disease and exists in specific disease processes).2 Malnutrition affects the function and institutional care and the community. recovery of every organ system. Approximately 5% of the UK population Dietary intake are underweight with a body mass index Muscle function (BMI) below 20 kg/m2, although obese Probably the single most important aeti- individuals who unintentionally lose ological factor in disease-related malnu- Weight loss due to depletion of fat and weight and subsequently have a BMI trition is reduced dietary intake. This is muscle mass, including organ mass, is within the normal range are also at risk of thought to occur due to reductions in often the most obvious sign of malnutri- malnutrition. Other patients become at appetite sensation as a result of changes tion. Muscle function declines before risk as a result of an acute event (eg small in cytokines, glucocorticoids, insulin and changes in muscle mass occur, suggesting bowel infarction), leaving them unable to insulin-like growth factors.6 The problem that altered nutrient intake has an meet their metabolic requirements both may be compounded in hospital patients important impact independent of the in the short and longer term. The preva- by failure to provide regular nutritious effects on muscle mass. Similarly, lence of malnutrition increases by at least meals in an environment where they are improvements in muscle function with twofold in the elderly and those with protected from routine clinical activities, nutrition support occur more rapidly chronic disease, and threefold in individ- and where they are offered help and sup- than can be accounted for by replace- uals living in institutional care.2 port with feeding when required.7 ment of muscle mass alone.2,9 The prevalence of malnutrition in UK Downregulation of energy dependent hospitals reported over the last 15 years Malabsorption cellular membrane pumping, or reductive ranges from 13–40%, many patients adaptation, is one explanation for these seeing a further decline in their nutri- For patients with intestinal failure and findings. This may occur following only a tional status during hospital admission.3 those undergoing abdominal surgical short period of starvation. If, however, A large survey conducted by the British procedures, malabsorption represents an dietary intake is insufficient to meet Association of Parenteral and Enteral independent risk factor for weight loss requirements over a more prolonged Nutrition (BAPEN) in 2008 found that and malnutrition. period of time the body draws on

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functional reserves in tissues such as psychosocial effects such as apathy, ated with disease-related malnutrition in muscle, adipose tissue and bone leading to depression, anxiety and self-neglect. the UK in 2007 were over £13 billion changes in body composition. With time, (greater than that for obesity). This there are direct consequences for tissue Malnutrition, clinical outcome calculation involved the summing of function, leading to loss of functional and the health economy treatment costs for both the underlying capacity and a brittle, but stable, meta- disease process and malnutrition. The bolic state. Rapid decompensation occurs Clinical outcome potential cost savings associated with with insults such as infection and trauma. prevention and treatment of malnutri- The consequences of malnutrition on Importantly, unbalanced or sudden exces- tion are considerable: a saving as small as physiological function have an important sive increases in energy intake also put 1% represents £130 million per year. impact on clinical outcome. In the 1930s malnourished patients at risk of decom- There is evidence that for specific surgeons observed that patients who were pensation and refeeding syndrome.6 situations treating malnutrition pro- starved or underweight had a higher inci- duces cost savings of 10–20% or more.12 dence of postoperative complications and Cardio-respiratory function mortality. A large number of studies have subsequently supported this original Assessment of nutritional status Reduction in cardiac muscle mass is observation. Malnourished surgical recognised in malnourished individuals. Identification of patients at risk of mal- patients have complication and mortality The resulting decrease in cardiac output nutrition at an early stage of hospital rates three to four times higher than nor- has a corresponding impact on renal admission (or attendance to the outpa- mally nourished patients, with longer function by reducing renal perfusion and tient clinic) allows for early intervention hospital admissions, incurring up to 50% glomerular filtration rate. Micronutrient with nutritional therapy. greater costs. Similar findings have also and electrolyte deficiencies (eg thiamine) been described in medical patients, par- may also affect cardiac function, particu- ticularly the elderly.2,10 It is often difficult larly during refeeding. Poor diaphrag- The Malnutrition Universal Screening to separate the deleterious effects of mal- matic and respiratory muscle function Tool (MUST) nutrition from the underlying disease reduces cough pressure and expectoration process itself, especially because each can MUST is a simple, rapid and easy of secretions, delaying recovery from res- be a cause and/or consequence of the method to screen patients and has been piratory tract infections. 11 other. However, there is clear evidence proven to be reliable and valid. It aims that nutrition support significantly to identify those at risk by incorporating: Gastrointestinal function improves outcomes in these patients; it is • current weight (BMI) Adequate nutrition is important for pre- therefore vital that malnutrition is identi- history of recent unintentional 11 • serving GI function: chronic malnutri- fied through screening. weight loss tion results in changes in pancreatic • likelihood of future weight loss. exocrine function, intestinal blood flow, The cost Figure 1 provides a guide for using villous architecture and intestinal perme- Malnutrition is also a major resource MUST. The total MUST score is a better ability. The colon loses its ability to reab- issue for public expenditure. BAPEN has predictor of outcome than scores from sorb water and electrolytes, and secretion recently calculated that the costs associ- the individual components. of ions and fluid occurs in the small and large bowel. This may result in diarrhoea, which is associated with a high mortality Key points rate in severely malnourished patients.

Malnutrition is a common, under-recognised and undertreated condition in hospital Immunity and wound healing patients

Immune function is also affected, increasing Disease-related malnutrition arises due to reduced dietary intake, malabsorption, the risk of infection due to impaired cell- increased nutrient losses or altered metabolic demands mediated immunity and cytokine, comple- Wide-ranging changes in physiological function occur in malnourished patients ment and phagocyte function. Delayed leading to increased rates of morbidity and mortality wound healing is also well described in malnourished surgical patients.2,9 Routine nutritional screening should be undertaken in all patients admitted to hospital using a validated tool such as the Malnutrition Universal Screening Tool

Psychosocial effects Healthcare costs are significantly increased in malnourished patients

In addition to these physical conse- KEY WORDS: clinical outcome, health economics, malnutrition, Malnutrition Universal quences, malnutrition also results in Screening Tool (MUST), screening

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Screening. The screening process iden- insufficient to ensure that nutritional Initiatives to improve nutritional tifies patients who require a more requirements are met need the addi- care detailed assessment and formulation tion of oral nutritional supplements or of an individualised stepwise manage- enteral tube feeding under dietetic Several publications7,13,14 from profes- ment plan by a nutrition specialist. In supervision. Patients rarely require sional and patient organisations, vulnerable patient groups the simple parenteral nutrition (PN). Need for including the Royal College of provision of regular meals or food PN usually occurs in the context of an Physicians, have highlighted the prob- with better nutritional content may be inaccessible or non-functioning GI lems associated with malnutrition. enough to address nutritional risk. tract. Rescreening of inpatients at Unfortunately, standards of care in many Additional measures may include seven-day intervals throughout a hos- institutions remain poor. Therefore, a broader menu choices or providing pital admission alerts clinicians to collaboration between the Department assistance with feeding. Patients in those who have lost weight and require of Health and stakeholders with an whom these ‘social’ interventions are greater intervention. interest and expertise in nutritional care

Fig 1. The Malnutrition Universal Screening Tool (MUST) BMI ϭ body Step 1 + Step 2 + Step 3 mass index. Reproduced with kind BMI score Weight loss score Acute disease effect score pemission of BAPEN.

BMI kg/m2 Score Uplanned If patient is acutely ill weight loss in and there has been past 3–6 months >20(>30 obese) = 0 or is likely to be no 18.5-20 = 1 % Score <5 = 0 nutritional intake for <18.5 = 2 5-10 = 1 >5 days Score 2 >10 = 2

Step 4 Overall risk of malnutrition Add scores together to calculate overall risk of malnutrition Score 0 low risk; Score 1 medium risk; Score 2 or more high risk

Step 5 Management guidelines 0 1 2 or more Low risk Medium risk High risk Routine clinical care Observe Treat* • Refer to dietitian, nutritional • Repeat screening: • Document dietary intake support team or implement Hospital – weekly for three days if subject in local policy Care homes – monthly hospital or care home • Improve and increase Community – annually • If improved or adequate overall nutritional intake for special groups intake – little clinical concern; • Monitor and review care eg those >75 years if no improvement – clinical plan: concern – follow local policy Hospital – weekly • Repeat screening Care home – monthly Hospital – weekly Community – monthly Care home – at least monthly • Unless detrimental or Community – at least every no benefit is expected from 2–3 months nutritional support eg imminant death.

All risk categories: Obesity: • Treat underlying condition and provide help and • Record presence of obesity. For those with advice on food choices, eating and drinking when underlying conditions, these are generally necessary. controlled before the treatment of obesity. • Record malnutrition risk category. • Record need for special diets and follow local policy.

Re-assess subjects identified at risk as they move through care settings see the ‘MUST’ explanatory booklet for further details and the ‘MUST’ report for supporting evidence.

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has published the Nutrition Action Plan at risk and allows appropriate treatment the hospital and the community, and clin- which sets out key priorities15 including: to be instituted; this can significantly ical and financial benefits of nutrition improve clinical outcomes and reduce intervention. Clin Nutr 1999;18(Suppl raising awareness 2):3–28. • healthcare expenditure. Every doctor 10 Stratton RJ, King CL, Stroud MA, Jackson • ensuring access to guidance should recognise that proper nutritional AA, Elia M. ‘Malnutrition Universal • promoting screening and training care is fundamental to good clinical Screening Tool’ predicts mortality and • clarifying standards. practice.14 By addressing deficiencies in length of hospital stay in acutely ill elderly. education of all healthcare professionals Br J Nutr 2006;95:325–30. The Care Quality Commission has 11 Elia M, Russell CA (eds); on behalf of identified nutritional care as one of the and exerting influence through clinical BAPEN and collaborators. The ‘MUST’ core standards which all acute trusts are leadership there can be genuine improve- Report. Nutritional screening for adults: a required to deliver, but not all services ments in nutritional care. multidisciplinary responsibility. Development and use of the ‘Malnutrition are inspected annually and patients con- Universal Screening Tool’ (MUST) for tinue to die as a consequence of malnu- References adults. A report by the Malnutrition trition. As a result, nutritional care has Advisory Group of the British Association 1 Elia M (ed.). Guidelines for detection and for Parenteral and Enteral Nutrition, 2003. been included in a new regulatory frame- management of malnutrition. Malnutrition work introduced in April 2010 for health 12 Elia M, Russell CA (eds). Combating mal- Advisory Group, Standing Committee of nutrition: Recommendations for action.A and social care services, which will BAPEN. Maidenhead: BAPEN, 2000. report from the Advisory Group on ensure that more attention is focused on 2 Stratton R, Green CJ, Elia M. Disease- Malnutrition, led by BAPEN. London: nutrition.16 At a local level, all hospitals related malnutrition: an evidence-based BAPEN. 2009. approach to treatment.Oxon:Cabi 13 Leonard-Jones JE (ed.). A positive approach should have an established multidiscipli- Publishing, 2003. nary nutrition support team for man- to nutrition as treatment. King’s Fund 3 Elia M, Stratton RJ. How much undernu- Report. London: King’s Fund Centre, 1992. aging patients with complex nutritional trition is there in hospitals? Br J Nutr 14 Royal College of Physicians. Nutrition and problems. Within each organisation 2000;84:257–9. patients: a doctor’s responsibility.Report of there should also be a nutrition steering 4 Russell CA, Elia M. Nutrition Screening a working party of the Royal College of Survey in the UK in 2008. Redditch, Physicians. London: RCP, 2002. committee to develop policies for nutri- Worcestershire: BAPEN, 2009. tional care, which should be regularly 15 Department of Health and the Nutrition 5 Finch S, Doyle W, Lowe C et al. National Summit Stakeholder Group. Improving audited as part of clinical governance diet and nutrition survey.London:The nutritional care: A joint action plan from the frameworks. Stationery Office, 1998. Department of Health and Nutrition Summit 6 Jackson AA. Severe malnutrition. In: stakeholder group. London: DH, 2007. Warrell DA, Cox TM, Firth JD, Benz EJ 16 Nutrition Action Plan Delivery Board: end of (eds). Oxford textbook of medicine, 4th edn, year progress report. London: DH, 2009. Conclusions vol 1. Oxford: Oxford University Press, 2003:1054–61. Malnutrition, which is often overlooked 7 Age Concern. Hungry to be heard. The by clinicians, is common and has wide- scandal of malnourished older people in hos- ranging effects on physiological func- pital. London: Age Concern, 2006. Address for correspondence: Dr T Smith, tion. It is associated with increased rates 8 Elia M. Changing concepts of nutrient Institute of Human Nutrition, of morbidity and mortality in hospital requirements in disease: implications for Mailpoint 113, Southampton artificial nutrition support. Lancet patients and significantly increases 1995;345:1279–84. University Hospitals, Tremona Road, healthcare costs. Implementation of a 9 Green CJ. Existence, causes and conse- Southampton SO16 6YD. simple screening tool identifies patients quences of disease-related malnutrition in Email: [email protected]