Rebecca J. Stratton

Disease-related malnutrition: an evidence-based approach to treatment.

Disease-related malnutrition is a global public health problem. The consequences of disease-related malnutrition are numerous, and include shorter survival rates, lower functional capacity, longer hospital stays, greater complication rates, and higher prescription rates. Nutritional support, in the form of oral nutritional supplements or tube feeding, has proven to lead to an improvement in patient outcome. This book is unique in that it draws together the results of numerous different studies that demonstrate the benefits of nutritional support and provides an evidence base for it. It also discusses the causes, consequences, and prevalence of disease-related malnutrition, and provides insights into the best possible use of enteral nutritional support.

The use of visual analogue scales to assess motivation to eat in human subjects: a review of their reliability and validity with an evaluation of new hand-held computerized systems for temporal tracking of appetite ratings

This present paper reviews the reliability and validity of visual analogue scales (VAS) in terms of (1) their ability to predict feeding behaviour, (2) their sensitivity to experimental manipulations, and (3) their reproducibility. VAS correlate with, but do not reliably predict, energy intake to the extent that they could be used as a proxy of energy intake. They do predict meal initiation in subjects eating their normal diets in their normal environment. Under laboratory conditions, subjectively rated motivation to eat using VAS is sensitive to experimental manipulations and has been found to be reproducible in relation to those experimental regimens. Other work has found them not to be reproducible in relation to repeated protocols. On balance, it would appear, in as much as it is possible to quantify, that VAS exhibit a good degree of within-subject reliability and validity in that they predict with reasonable certainty, meal initiation and amount eaten, and are sensitive to experimental manipulations. This reliability and validity appears more pronounced under the controlled (but more artificial) conditions of the laboratory where the signal:noise ratio in experiments appears to be elevated relative to real life. It appears that VAS are best used in within-subject, repeated-measures designs where the effect of different treatments can be compared under similar circumstances. They are best used in conjunction with other measures (e.g. feeding behaviour, changes in plasma metabolites) rather than as proxies for these variables. New hand-held electronic appetite rating systems (EARS) have been developed to increase reliability of data capture and decrease investigator workload. Recent studies have compared these with traditional pen and paper (P&P) VAS. The EARS have been found to be sensitive to experimental manipulations and reproducible relative to P&P. However, subjects appear to exhibit a significantly more constrained use of the scale when using the EARS relative to the P&P. For this reason it is recommended that the two techniques are not used interchangeably.

Systematic review and meta-analysis of the effects of high protein oral nutritional supplements

Disease-related malnutrition is common, detrimentally affecting the patient and healthcare economy. Although use of high protein oral nutritional supplements (ONS) has been recommended to counteract the catabolic effects of disease and to facilitate recovery from illness, there is a lack of systematically obtained evidence to support these recommendations. This systematic review involving 36 randomised controlled trials (RCT) (n=3790) (mean age 74 years; 83% of trials in patients >65 years) and a series of meta-analyses of high protein ONS (>20% energy from protein) demonstrated a range of effects across settings and patient groups in favour of the high protein ONS group. These included reduced complications (odds ratio (OR) 0.68 (95%CI 0.55-0.83), p<0.001, 10 RCT, n=1830); reduced readmissions to hospital (OR 0.59 (95%CI 0.41-0.84), p=0.004, 2 RCT, n=546); improved grip strength (1.76 kg (95%CI 0.36-3.17), p<0.014, 4 RCT, n=219); increased intake of protein (p<0.001) and energy (p<0.001) with little reduction in normal food intake and improvements in weight (p<0.001). There was inadequate information to compare standard ONS (<20% energy from protein) with high protein ONS (>20% energy from protein). The systematic review and meta-analysis provides evidence that high protein supplements produce clinical benefits, with economic implications.

A systematic review and meta-analysis of the impact of oral nutritional supplements on hospital readmissions

The adverse effects of disease-related malnutrition (DRM) on health care use and costs are well substantiated. However, the impact of managing DRM with nutritional support on health care use, including hospital (re)admissions requires exploration. This systematic review (9 RCT, N=1190) examined the effects of oral nutritional supplements (ONS) on hospital (re)admissions. Meta-analysis of 6 RCT (N=852) with data on the proportion of patients (re)admitted to hospital showed significant reductions with ONS vs. routine care (OR 0.59, 95% CI 0.43-0.80, P=0.001), including 5 RCT (N=826) that recorded readmissions (OR 0.59, 95% CI 0.43-0.80, P=0.001). The significant reduction in (re)admissions was found in meta-analyses of ONS trials in various settings and in patients with DRM or of varied nutritional status. A larger meta-analysis (8 RCT, N=999) that combined other (re)admissions data using standardised differences also showed a significant reduction with ONS (effect size -0.23, 95% CI -0.36 to -0.10, P=0.001). Most of these trials (75%) were in older people aged ≥65 years (6 RCT, N=834, effect size -0.18, 95% CI -0.31 to -0.04, P=0.011). This systematic review shows that ONS significantly reduce hospital (re)admissions, particularly in older patient groups, with economic implications for health care.

An analytic appraisal of nutrition screening tools supported by original data with particular reference to age

OBJECTIVE Controversies exist as to the suitability of various nutrition screening tools for various age groups, the incorporation of age and age-related criteria into some tools, and the procedures associated with tool selection. METHODS Reviews of the literature and national and local datasets were used to identify the types of screening tools available for different age groups, the origins of age-related criteria, and the value of tool selection procedures based on predicting clinical outcomes. RESULTS Nutrition screening can be undertaken in fetuses, children, and adults over narrow or wide age ranges, for diagnostic or prognostic purposes, with or without nutritional interventions. Certain tools can establish malnutrition risk without using any nutritional criteria, whereas others can do so only with nutritional criteria. The incorporation of age and age-specific body mass index criteria into adult screening tools can influence the prevalence and age distribution of malnutrition, but no justification is usually provided for their use. In several circumstances, age alone can predict mortality and length of hospital stay much better than screening tools. We identified various methodologic problems in nutrition screening tool selection. CONCLUSIONS A comparison of nutrition screening tools designed for different age groups and different purposes can be problematic. Age and screening tools incorporating risk factors that are non-modifiable or generally weakly modifiable by nutritional support (e.g., age, disease severity) may predict outcomes of disease, but they are not necessarily suitable for predicting outcomes of nutritional support. To contextualize the findings, a framework for screening tool selection is suggested that takes into account a matrix of needs.

Nutritional support and functional capacity in chronic obstructive pulmonary disease: a systematic review and meta-analysis.

Currently, there is confusion about the value of using nutritional support to treat malnutrition and improve functional outcomes in chronic obstructive pulmonary disease (COPD). This systematic review and meta‐analysis of randomized, controlled trials (RCT) aimed to clarify the effectiveness of nutritional support in improving functional outcomes in COPD. A systematic review identified 12 RCT (n = 448) in stable COPD patients investigating the effects of nutritional support (dietary advice (1 RCT), oral nutritional supplements (10 RCT), enteral tube feeding (1 RCT)) versus control on functional outcomes. Meta‐analysis of the changes induced by intervention found that while respiratory function (forced expiratory volume in 1 s, lung capacity, blood gases) was unresponsive to nutritional support, both inspiratory and expiratory muscle strength (maximal inspiratory mouth pressure +3.86 standard error (SE) 1.89 cm H2O, P = 0.041; maximal expiratory mouth pressure +11.85 SE 5.54 cm H2O, P = 0.032) and handgrip strength (+1.35 SE 0.69 kg, P = 0.05) were significantly improved and associated with weight gains of ≥2 kg. Nutritional support produced significant improvements in quality of life in some trials, although meta‐analysis was not possible. It also led to improved exercise performance and enhancement of exercise rehabilitation programmes. This systematic review and meta‐analysis demonstrates that nutritional support in COPD results in significant improvements in a number of clinically relevant functional outcomes, complementing a previous review showing improvements in nutritional intake and weight.

Considerations for screening tool selection and role of predictive and concurrent validity.

Purpose of reviewNutrition screening tool selection can be difficult. This review critically examines the relevance of validity, specifically concurrent (agreement between tools) and predictive validity (prediction of outcomes), which have been the focus of several recent studies. An operational framework for screening tool selection is provided to contextualise the findings. Recent findingsStudies of predictive and concurrent validity involving screening tools comprising a variable number of nutritional and non-nutritional items (some nonmodifiable) have yielded inconsistent results. The use of one tool as a gold standard to judge the relative merits of other tools can be misleading because there is no agreed gold standard and different tools were designed for diagnostic, prognostic or other purposes. The use of observed outcomes (without nutritional intervention) as the gold standard may not adequately reflect the value of tools designed to assess nutritional status and need for nutritional intervention. SummaryOver-reliance on concurrent and predictive validity can be confusing and even counter-productive if used inappropriately. A proposed framework for screening tool selection indicates many factors should be considered so that there is purpose and harmony between the screening tool and the screening programme.

Techniques for the study of energy balance in man

Energy balance can be estimated in tissues, body segments, individual subjects (the focus of the present article), groups of subjects and even societies. Changes in body composition in individual subjects can be translated into changes in the energy content of the body, but this method is limited by the precision of the techniques. The precision for measuring fat and fat-free mass can be as low as 0.5 kg when certain reference techniques are used (hydrodensitometry, air-displacement plethysmography, dual-energy X-ray absorptiometry), and approximately 0.7 kg for changes between two time points. Techniques associated with a measurement error of 0.7 kg for changes in fat and fat-free mass (approximately 18 MJ) are of little or no value for calculating energy balance over short periods of time, but they may be of some value over long periods of time (18 MJ over 1 year corresponds to an average daily energy balance of 70 kJ, which is < 1% of the normal dietary energy intake). Body composition measurements can also be useful in calculating changes in energy balance when the changes in body weight and composition are large, e.g. > 5-10 kg. The same principles can be applied to the assessment of energy balance in body segments using dual-energy X-ray absorptiometry. Energy balance can be obtained over periods as short as a few minutes, e.g. during measurements of BMR. The variability in BMR between individuals of similar age, weight and height and gender is about 7-9%, most of which is of biological origin rather than measurement error, which is about 2%. Measurement of total energy expenditure during starvation (no energy intake) can also be used to estimate energy balance in a whole-body calorimeter, in patients in intensive care units being artificially ventilated and by tracer techniques. The precision of these techniques varies from 1 to 10%. Establishing energy balance by measuring the discrepancy between energy intake and expenditure has to take into consideration the combined validity and reliability of both components. The measurement error for dietary intake may be as low as 2-3% in carefully controlled environments, in which subjects are provided only with certain food items and bomb calorimetry can be undertaken on duplicate samples of the diet. Reliable results can also be obtained in hospitalised patients receiving enteral tube feeding or parenteral nutrition as the only source of nutrition. Unreliability increases to an unknown extent in free-living subjects eating a mixed and varied diet; thus, improved methodology is needed for the study of energy balance.

Encouraging appropriate, evidence-based use of oral nutritional supplements.

With the considerable cost of disease-related malnutrition to individuals and to society (estimated to be >£13×109 for the UK, 2007 prices), there is a need for effective and evidence-based ways of preventing and treating this condition. The wide range of oral nutritional supplements that may be prescribed for the dietary management of malnutrition and other conditions account for only about 1% (about £99×106, 2007 data) of the prescribing budget in England. Systematic reviews and meta-analyses consistently suggest that ready-made, multi-nutrient liquids which may be prescribed can improve energy and nutritional intake, body weight and have a variety of clinical and functional benefits in a number of patient groups. Meta-analyses have repeatedly shown that oral nutritional supplements produce significant reductions in complications (e.g. infections) and mortality, and a recent meta-analysis shows a reduction in hospital admissions (OR 0·56 (95% CI 0·41, 0·77), six randomised controlled trials). Such benefits suggest that the appropriate use of oral nutritional supplements should form an integral part of the management of malnutrition, particularly as there is currently a lack of evidence for alternative oral nutrition strategies (e.g. food fortification and counselling). As with all therapies, compliance to oral nutritional supplements needs to be maximised and the use monitored. To make sure that those at risk of malnutrition are identified and treated appropriately, there is a need to embed national and local policies into routine clinical practice. In doing so, the economic burden of this costly condition can be curtailed. As recently suggested by the National Institute for Health and Clinical Excellence, substantial cost savings could be made if screening and treatment of malnourished patients was undertaken.

Description and evaluation of a Newton-based electronic appetite rating system for temporal tracking of appetite in human subjects.

This study assessed the reliability and validity of a palm-top-based electronic appetite rating system (EARS) in relation to the traditional paper and pen method. Twenty healthy subjects [10 male (M) and 10 female (F)] - mean age M=31 years (S.D.=8), F=27 years (S.D.=5); mean BMI M=24 (S.D.=2), F=21 (S.D.=5) - participated in a 4-day protocol. Measurements were made on days 1 and 4. Subjects were given paper and an EARS to log hourly subjective motivation to eat during waking hours. Food intake and meal times were fixed. Subjects were given a maintenance diet (comprising 40% fat, 47% carbohydrate and 13% protein by energy) calculated at 1.6xResting Metabolic Rate (RMR), as three isoenergetic meals. Bland and Altmans test for bias between two measurement techniques found significant differences between EARS and paper and pen for two of eight responses (hunger and fullness). Regression analysis confirmed that there were no day, sex or order effects between ratings obtained using either technique. For 15 subjects, there was no significant difference between results, with a linear relationship between the two methods that explained most of the variance (r(2) ranged from 62.6 to 98.6). The slope for all subjects was less than 1, which was partly explained by a tendency for bias at the extreme end of results on the EARS technique. These data suggest that the EARS is a useful and reliable technique for real-time data collection in appetite research but that it should not be used interchangeably with paper and pen techniques.