Editorial Comment: Protein-Energy Undernutrition and Acute Stroke Outcome
Stroke is a common and devastating event that often results in death or major loss of independence with immense human and financial costs. Approximately 125 000 and 500 000 new or recurrent strokes occur each year in the United Kingdom and United States, respectively. The majority of strokes are not fatal, and the major burden is long-term disability. It is therefore the most important single cause of severe disability among Western people living in their own homes.1 Stroke in the developing world is less well documented. A statement from the Asia-Pacific Consensus Forum on Stroke Management predicts that ‘In the next 30 years or so the burden of stroke will grow most in developing countries rather than in the developed world.‘2
Stroke produces an almost infinite range of possible combinations of loss of function such as difficulties in swallowing, hemiplegia, impaired consciousness, perceptual deficits, visual fields defects, cognitive impairment, and motor apraxia or paralysis. These deficits will have an obvious and variable impact on the stroke patient’s nutritional demands and actual intake. Many studies have shown that a significant number of stroke patients were undernourished on admission and their nutritional status deteriorated further while in hospital. Undernutrition was associated with increasing morbidity and mortality.3-5⇓⇓ However, most of these studies suffered from methodological limitations.
In this issue of Stroke, Dennis et al6 report the results of an observational multicenter study of the relationship between baseline nutritional status and 6-month clinical outcome in 2955 hospitalized stroke patients. Their results indicate that baseline nutritional status was independently associated with clinical outcome.
The authors were able to study and follow a large sample of stroke patients recruited from a wide range of hospitals around the world, which does increase the external validity of the results. They used a simple bedside method performed by the randomizing clinician to categorize patients as “undernourished, normal, or overweight” (60% of patients) or, where practical, a fuller assessment of nutritional status. The findings indicate that 9% of those enrolled were judged undernourished and 16% overweight and that undernutrition was associated with poor outcome. This is an important result and a welcome advance in knowledge.
All studies have their limitations, and in very large multicenter studies like this one, the essential simplicity of the assessment method may lead to concerns over the reliability and validity of the nutritional status assessments. The authors are well aware of this and have performed assessments of interobserver reliability among a range of healthcare professionals. As of yet there is no “gold standard” for determining nutritional status because there is no universally accepted definition of undernutrition and all current assessment parameters are affected by age-related changes, disability, illness, and injury.7
Another important issue in this report is distinguishing underlying comorbidity from undernutrition, and to separate their effects on the stroke patient’s outcome. This is, however, one of the principal challenges that have always faced modern old people medicine. The authors have acknowledged this weakness, but more importantly they have adjusted for a number of poor prognostic factors such as age, prestroke dependency, and stroke severity, which together may, to some extent, reflect the patient’s frailty and comorbidity.
Elderly patients including strokes are likely to have poor nutritional status prior to hospital admission, which may be associated with impaired immune defensive responses.8 Their nutritional status is likely to deteriorate further as the result of the catabolism associated with the acute illness.9 During the stroke patient’s rehabilitation, nutritional depletion, however, may be more serious than during acute illness, given that rehabilitation periods may extend over weeks and months, and deterioration in nutritional status, although less marked than in the early catabolic phase, may be greater overall.10 A number of recent reports have indicated that poor nutritional status following acute illness in aging patients including strokes may be of more prognostic significance and amenable to therapy later on during the convalescent phase.5,11–13⇓⇓⇓
This important study highlights 2 of the main challenges in understanding the interaction of nutrition, aging, and disease. The first is to find a valid, reliable, and practical way of measuring aging patients’ nutritional status in routine clinical practice. The authors of this article have “validated” an approach to meeting this challenge. The second is to determine the optimal timing, route, and composition of nutritional therapy relative to a patient’s metabolic stress, age, and specific illness.
Whether the relationship between undernutrition and poor stroke outcome reported in this issue of Stroke is a causal one or a mere association needs to be determined. Nevertheless, the authors of this report have provided us with the strongest evidence yet that this may indeed be the case. Confirmation of this relationship must await results of the interventional arm of their study.
- ↵Martin J, Meltzer H, Elliot D. OPCS survey of disability in Great Britain Report, I: the prevalence of disability among adults. Office of Population Census and Survey. London: Her Majesty’s Stationery Office; 1988.
- ↵Unosson M, Ek AC, Bjurulf P, von Schenck H, Larsson J. Feeding dependence and nutritional status after acute stroke. Stroke. 1994; 25: 366–371.
- ↵Gariballa SE, Taub N, Parker SG, Castleden CM. The influence of nutritional status on clinical outcome after acute stroke. Am J Clin Nutr. 1998; 68: 275–281.
- ↵Davalos A, Ricart W, Gonzalez-Huix F, Soler S, Marrugat J, Molins A, et al. Effect of malnutrition after acute stroke on clinical outcome. Stroke. 1996; 27: 1028–1032.
- ↵FOOD Trial Collaboration. Poor nutritional status on admission predicts poor outcome after stroke: observational data from the FOOD trial. Stroke. 2003; 34: 1450–1455.
- ↵Klein S, Kinney J, Jeejeebhoy K, Alpers D, Hellerstein M, Murray M, Twomey P. Nutrition support in clinical practice: review of published data. Am J Clin Nutr. 1997; 66: 683–706.
- ↵Friedmann JM, Jensen GL, Smiciklas-Wright H, McCamish MA. Predicting early nonelective hospital readmission in nutritionally compromised older adults. Am J Clin Nutr. 1997; 65: 1714–1720.