Nutrition is an essential and yet often forgotten part of hospital care. According to one study¹ as many as 40% of patients in the UK hospitals may be undernourished at admission and most of them lose more weight during their stay. With water considered an essential nutrient, dehydration is closely related to undernutrition, with some experts suggesting that hydration status should be a necessary accompaniment of the nutritional assessment². Yet studies report that hydration is frequently overlooked at admission and that many patients become dehydrated in the hospital.³

Link between nutrition and infection

Nutrition and infection operate a vicious synergistic cycle.⁴ Malnutrition predisposes to infection and increases its severity. Infection increases energy requirements but also reduces appetite, decreases nutrient utilisation and promotes the breakdown of lean mass. It is sometimes difficult to establish which came first, but ultimately one exacerbates the other.

Several mechanisms for infection have been identified. In protein-energy malnutrition (PEM) there may be no amino acids to produce the cytokines (signalling molecules produced by immune system) and there may be no available energy to supply the needs of rapidly dividing immune cells.⁵ This is likely to affect patients who are acutely or chronically undernourished. In contrast, micronutrient deficiencies such as iron, zinc or vitamins A, C or D, which have also been shown to play an important part in immune system are more likely to affect patients with long-term underfeeding issues. Chronic deficiency of these compromises the body’s ability to mount the normal immune response and decreases the production of white blood cells.⁴

The link between hydration and infection is less well defined. One 2005 study⁶ reported that in the well-hydrated rabbits injected with Vaccinia, the virus was localised and not able to infect the surrounding tissues. The mechanism behind this seemed to be a decreased permeability of the cells. Bacterial infections, especially those of respiratory and urinary tract are common in subjects diagnosed with dehydration as observed in some epidemiological studies, although it is usually difficult to establish which precipitated the other. The casual relationship has been observed in another older study which reported incidence of dehydration alone as 3.21 and dehydration with infection as 11.60 per 1000 hospitalised older adults.⁷

Nutrition and healthcare-associated infections

Only a few studies assessed the effect of malnutrition on developing healthcare-associated infections (HCAIs). A recent cross-sectional study published in the Journal of Hospital Infection⁸ demonstrated that patients who developed HCAIs were more likely to be at high risk of malnutrition, although these patients were also more likely to have a surgery, central venous catheter or urinary catheter in situ. Other observational studies showed an increased risk of developing HCAIs in different healthcare settings. In one study⁹ of 248 patients requiring emergency admission to a hospital in Greece, 28% of patients who were undernourished developed HCAI during the hospital stay as opposed to 20% of those who were not. Another study¹⁰, which followed 1180 hip fracture patients admitted to orthopaedic units showed that those with BMI <20kg/m² were more likely to develop HCAIs whilst in hospital than those who were normal weight. However, the incidence of HCAI was similar in the obese patients, suggesting a potential U-shaped relationship. Yet another study conducted in nursing homes¹¹ reported a higher incidence rate of HCAI in the eight month follow up period in the undernourished residents (2.22/1000 patient days vs 1.31/1000pd in the well-nourished group).

Improving nutritional status of undernourished patients seems to have some  beneficial effect. One randomised control trial¹², which used essential amino acid supplementation in patients with hypoalbuminemia due to malnutrition, reported that those in control group were able to gain weight and had 30% lower incidence of HCAIs than those in a control group. In another controlled trial² of patients admitted to a geriatric hospital, those in the intervention group who received personalised multidisciplinary nutritional support were reported to develop 36% less HCAIs than those receiving standard care. However, another study¹³ which also used personal nutritional support showed no effect with the infection rates being low in both support and standard care group.

There are so far no published studies describing the link between hydration status and HCAI. Few studies describe an increased incidence of urinary tract^14-18 and respiratory infections^19-23, but these are not specifically linked to healthcare. In fact, the evidence for these infections is still scarce. Some of the reasons for this may be that establishing hydration status is difficult, it is not always assessed during hospital stay, and that infection and dehydration usually coexist at the time of diagnosis making it difficult to established which developed first. Additionally, it would be difficult to assess the risk of HCAI for those who were diagnosed as dehydrated because it would have been unethical leaving the condition to be untreated.

Summary

While the majority of the studies show a potential of adequate nutrition and hydration to prevent the development of HCAIs, the evidence is still relatively scarce. But isn’t it worth it? Improving nutritional status may also have a positive effect on other outcomes such as improved quality of life^2,13, lower mortality¹³, shorter hospital stay^2,9 and reduced treatment cost². 

1 Hickson M, Bulpitt C, Nunes M, Peters R, Cooke J, Nicholl C, et al. Does additional feeding support provided by health care assistants improve nutritional status and outcome in acutely ill older in-patients?--a randomised control trial. Clinical Nutrition. 2004 Feb;23(1):69-77.

2 Rypkema G, Adang E, Dicke H, Naber T, de Swart B, Disselhorst L, et al. Cost-effectiveness of an interdisciplinary intervention in geriatric inpatients to prevent malnutrition. J Nutr Health Aging. 2004;8(2):122-7.

3 Thomas DR, Cote TR, Lawhorne L, Levenson SA, Rubenstein LZ, Smith DA, et al. Understanding clinical dehydration and its treatment. J Am Med Dir Assoc. 2008 Jun;9(5):292-301.

4 Macallan D. Infection and malnutrition. Medicine. 2009;37(10):525-8.

5 Shetty P. Malnutrition and undernutrition. Medicine. 2006 12;34(12):524-9

6 Arinzon Z, Feldman J, Peisakh A, Zuta A, Berner Y. Water and sodium disturbances predict prognosis of acute disease in long term cared frail elderly. Arch Gerontol Geriatr. 2005 May-Jun;40(3):317-26.

7 Bonner J, Harris W. Healthy aging: new directions in health, biology and medicine. Claremont, CA: Hunter House; 1988.

8 Fitzpatrick F, Skally M, O'Hanlon C, Foley M, Houlihan J, GaughanL, Smith O, Moore B, Cunneen S, Sweeney E, Dinesh B, O'Connell K, Smyth E, Humphreys H, Burns K. Food for thought. Malnutrition risk associated with increased risk of healthcare-associated infection. J Hosp Infect. 2019 Mar;101(1):.

9 Gamaletsou MN, Poulia KA, Karageorgou D, Yannakoulia M, Ziakas PD, Zampelas A, et al. Nutritional risk as predictor for healthcare-associated infection among hospitalized elderly patients in the acute care setting. J Hosp Infect. 2012 Feb;80(2):168-72.

10 Batsis JA, Huddleston JM, Melton LJ, Huddleston PM, Larson DR, Gullerud RE, et al. Body mass index (BMI) and risk of noncardiac postoperative medical complications in elderly hip fracture patients: A population-based study. Journal of Hospital Medicine. 2009;4(8):E1-9.

11 Kuikka LK, Salminen S, Ouwehand A, Gueimonde M, Strandberg TE, Finne-Soveri UH, et al. Inflammation Markers and Malnutrition as Risk Factors for Infections and Impaired Health-Related Quality of Life Among Older Nursing Home Residents. Journal of the American Medical Directors Association. 2009 6;10(5):348-53

12 Aquilani R, Viglio S, Barbieri A, D'Agostino L, Verri M, Pasini E, et al. Effects of oral amino acid supplementation on long-term-care-acquired infections in elderly patients. Arch Gerontol Geriatr. 2011;52(3):e123-8.

13 Johansen N, Martinsen A, Kondrup J, Plum LM, Bak L, Nørregaard P, et al. Effect of nutritional support on clinical outcome in patients at nutritional risk. Clinical Nutrition. 2004;23(4):539-50

14 Wang J, Su S, Guo H. Urinary Tract Infection among Clean-Room Workers. J Occup Health. 2002;44(5):329-33.

15 Mazzola BL, von Vigier RO, Marchand S, Tonz M, Bianchetti MG. Behavioral and functional abnormalities linked with recurrent urinary tract infections in girls. J Nephrol. 2003 Jan-Feb;16(1):133-8.

16 Stauffer C, van der WEG B, Donadini R, Ramelli G, Marchand S, Bianchetti M. Family history and behavioral abnormalities in girls with recurrent urinary tract infections: a controlled study. J Urol. 2004 Apr;171(4):1663-5.

17 Rudaitis S, Pundziene B, Jievaltas M, Uktveris R, Kevelaitis E. Recurrent urinary tract infection in girls: do urodynamic, behavioral and functional abnormalities play a role? J Nephrol. 2009 Nov-Dec;22(6):766-73.

18 Mentes JC, Culp K. Reducing hydration-linked events in nursing home residents. Clin Nurs Res. 2003 Aug;12(3):210-25.

19 Mahowald JM, Himmelstein DU. Hypernatremia in the elderly: Relation to infection and mortality. J Am Geriatr Soc. 1981 Apr;29(4):177-80.

20 Mahowald JM, Himmelstein DU. Hypernatremia in the elderly: Relation to infection and mortality. J Am Geriatr Soc. 1981 Apr;29(4):177-80.

21 Warren JL, Bacon WE, Harris T, McBean AM, Foley DJ, Phillips C. The burden and outcomes associated with dehydration among US elderly, 1991. Am J Public Health. 1994 Aug;84(8):1265-9.

22 Szafara KL, Kruse RL, Mehr DR, Ribbe MW, van der Steen JT. Mortality following nursing home-acquired lower respiratory infection: LRI severity, antibiotic treatment, and water intake. J Am Med Dir Assoc. 2012 May;13(4):376-83.

23 Lin L, Hsieh P, Wu S. Prevalence and associated factors of pneumonia in patients with vegetative state in Taiwan. J Clin Nurs. 2008 Apr;17(7):861-8.