The Effectiveness of Oral Nutritional Supplements for the Management of Malnutrition: a Systematic Review and Meta-Analysis
Malnutrition is the deficiency, imbalance or excess of energy, protein or other nutrients that causes measurable adverse effects on the body, the way it functions and clinical outcomes. Prevalence is high across all care settings, causing measurable adverse outcomes for individuals and the healthcare economy. The National Institute of Health and Care Excellence (NICE) Clinical Guideline 32 recommends regular screening for anyone accessing healthcare as well as the provision of nutrition support for anyone with malnutrition. Oral nutritional supplements (ONS) can be prescribed when food alone is insufficient to meet nutritional requirements. ONS are a clinically and cost-effective way to manage malnutrition without suppressing natural appetite but, research has been limited to specific patient groups and clinical settings. As malnourished patients are found in varying clinical conditions, across all care settings, there is insufficient evidence that can be generalised to all patients prescribed ONS for malnutrition. The aim of this review will be to evaluate the effectiveness of ONS for the entire malnourished population. The objectives are to carry out a systematic search into the use of ONS in randomised controlled trials (RCTs) from 2007-2019 and to critically review how effective ONS are for improving patient outcomes. The Bath Spa University online library, Science Direct, Cochrane database, PubMed and Google Scholar will be used to identify relevant RCTs. Search terms will be used both in isolation and combination, including: “sip”, “adult”, “nutrition”, “oral nutritional supplement”, “ONS”, “nutrition support”, “enteral” and “effectiveness”. Each patient outcome reported in the RCTs will be categorised as either clinical, functional or nutritional. Outcomes will be analysed individually and compared between the categories using odds ratio (OR), relative risk (RR), a fixed-effects model, a generalised model (GM) and a generalised linear model (GLM) to investigate relationships and size of effects between ONS effectiveness and patient outcomes. Meta-analysis will provide information for industry and healthcare professionals to show the effectiveness of ONS in a broad context that is generalisable to all malnutrition patients.
Malnutrition is the deficiency, imbalance or excess of energy, protein or other nutrients that causes measurable adverse effects on the body, the way it functions and clinical outcomes (BAPEN, 2003). This report will refer to malnutrition in the context of nutritional deficiency. Malnutrition is widespread in the UK, affecting more than 3 million people (BAPEN, 2015). Prevalence is high across all care settings and 93% of all malnourished patients reside in the community (Stratton, Green and Elia, 2003; Elia and Russell, 2009). Up to 34% of care home residents (Russell and Elia, 2015), 29% of patients on admission to hospital (Elia, 2015) and 30% of hospital outpatients are found be malnourished (Stratton et al., 2004). The primary cause is reduced or inadequate nutritional intake, usually in old age and chronic or acute illness (Brotherton, Simmonds and Stroud, 2010).
Malnutrition is associated with adverse individual and economic outcomes (Elia and Stratton 2009). Individual outcomes are categorised as: clinical (increased complications, length of hospital stay, readmissions, increased mortality); functional (decreased quality of life, strength, activities of daily living, mobility, breathlessness) and nutritional (reduced intake, appetite, weight, body composition) (Cawood, Elia and Stratton, 2012). Due to increased healthcare use, adverse individual outcomes have a direct economic strain on the National Health Service (NHS) (Meijers et al., 2012). Cost-saving reports show that annual expenditure on malnutrition in the UK exceeds £26 billion; this is more than 15% of the entire health and social care budget (Elia, 2015). Additionally, the annual cost of treating a malnourished patient is estimated to be over 3 times greater (£7408) than a non-malnourished patient (£2155) (Elia, 2015). Regardless of severe individual and economic burdens, reports consistently show that malnutrition remains under-diagnosed and under-reported within the NHS (Elia, 2015).
The National Institute of Health and Care Excellence (NICE) recommend that anyone accessing healthcare services is regularly screened for malnutrition using a validated screening tool (NICE, 2006). There are a range of validated screening tools available for healthcare professionals to use. The NHS standard is the Malnutrition Universal Screening Tool (‘MUST’), a 5-step process to assess nutritional status (BAPEN, 2019). Using this tool, patients are given a score which translates to ‘low’, ‘medium’ or ‘high’ risk of malnutrition. A range of nutrition support strategies should be considered for any patients rated medium or high risk (Saunders and Smith, 2010; NICE 2006). Nutrition support can include dietary modification (the addition of high energy snacks or cooking ingredients to usual diet), oral nutritional supplements (ONS) and/or artificial nutritional support (enteral or parenteral tube feeding). This review will focus on ONS as a method of nutrition support. Most ONS are available for NHS reimbursement and can be prescribed in addition to diet when food alone is insufficient to meet nutritional requirements (Gandy, 2019). Appropriate prescribing of ONS has been found to be a clinically effective way to manage malnutrition by maximising nutritional intake without suppressing natural appetite (Cawood, Elia and Stratton, 2012; Stratton and Elia, 2007). Clinical trials have shown that ONS are effective for specialised patient groups including oncology, cardiovascular, orthopaedic, neurological and degenerative diseases (Parsons et al., 2017). Findings that can be generalised to all patients with malnutrition regardless of other clinical conditions are lacking. (Parsons et al., 2017). There is conflicting data on the effectiveness of ONS due to the use of flawed methodology (Parsons et al., 2017), such as, studies where ONS were unfinished (low compliance) or where ONS were provided alongside dietary modification interventions (Bruce et al., 2003). New research has not been assimilated into a review on the effectiveness of ONS for all malnourished patients when compliance is high, and without the risk of dietary modification affecting the findings (Stratton and Elia, 2007).
The aim of this paper is to systematically review and analyse the effectiveness of appropriately prescribed ONS for the management of malnutrition in the entire malnourished population. The objectives are to carry out a systematic search into the use of ONS in randomised controlled trials (RCTs) from 2007-2019 and to critically review and analyse how effective ONS are at managing malnutrition to improve nutritional, clinical and functional patient outcomes.
Critical literature review
There is an extensive literature base that recognises the use of ONS for the management of malnutrition. Evidence is assimilated by NICE in Clinical Guideline 32 (CG32), a document that provides clear and succinct guidance for healthcare professionals (NICE, 2006). The document reviewed and analysed 40 RCTs that evaluated the effectiveness of ONS and found statistically significant increases in weight and reductions in mortality compared to standard care (p<0.05) (NICE, 2006). A review of CG32 was undertaken in 2017 by NICE and 242 new studies were highlighted for consideration. However, no evidence was found to have a contradictory impact on the existing guideline, so it remained largely the same (NICE, 2019). Despite informing healthcare professionals across the UK, CG32 is not without limitations. The opportunity for meta-analysis was limited due to small trials, data heterogeneity and fundamental differences in intervention and outcome measures between trials (NICE, 2019). As most trials have been conducted in hospitals, evidence that can be applied to a community setting is lacking. However, since the CG32 2017 review, several studies have been conducted in the community (Parsons et al., 2017; Jobse et al., 2015). The findings from these studies should be utilised and incorporated into CG32 to effectively address the issue of low generalisability to the community setting. This review will include research across all care settings. Finally, CG32 fails to address the issue of patient compliance (‘the extent to which a person’s behaviour corresponds with agreed recommendations from a healthcare provider’) to ONS (WHO, 2003). The effectiveness of ONS will vary in correlation with how compliant the patient is to the prescription and acknowledgement of patient compliance issues would be useful for healthcare professions using CG32.
Research on compliance to ONS varies from poor (14.9%) (Lawson et al., 2000) to excellent (93%) (Lijeberg et al, 2019). Reduced compliance is usually ascribable to low patient acceptance of the supplements (dislike of sensory attributes, often taste and texture) and side effects (gastrointestinal upset) (Lijeberg et al., 2019). Low compliance (14.9%) was shown in a hospital trial (n=187) and this data is still cited in current research despite several methodological limitations (Lawson et al., 2000). Lawson’s work only studied inpatients after invasive surgery. Therefore, it does not examine compliance rates between different clinical conditions or settings, nor does it address the issue that nutritional intake typically declines in times of acute illness (Morley, 2017). Furthermore, this trial was published in 2000. If Lawsons work were to be replicated, findings may differ due to constantly improving ONS formulations (Lad, Gott and Garribala, 2005). Research published in 2019 that used similar methodology and current ONS formulations has found 76-93% compliance (Lijeberg et al., 2019). This can be partially attributed to high patient acceptance; more than 70% of patients claimed to like the taste of ONS (Lijeberg et al., 2019). Studies comparing compliance using both old and newer formulations would have been useful to evaluate how compliance has changed over time, but there is no research of this nature available. Compliance data been assimilated in a systematic review of 46 controlled trials (n=4328) and the overall pooled mean compliance to ONS was found to be 78.2% (SD 15) (Hubbard et al., 2012). A varied range of patients in all care settings were analysed and compliance was significantly greater in community studies (80.9%) than in hospital studies (67.2%) (p=0.013). This is a more current and generalisable measure of compliance than Lawson’s study showing only 14.9% compliance (Lawson, 2000).
When compliance is high, as indicated by Hubbard et al., many arguments stating the ineffectiveness of ONS are invalidated (Hubbard et al., 2012). However, dietary modification is another factor known to affect patient compliance to ONS. Patients have been known to object to ONS, preferring to make dietary modifications to increase their nutrient intake (Lovelsely, Parasuraman and Ramanurthy, 2019). As patient acceptability of ONS has increased, the preference for dietary modification has declined (Lovelsely, Parasuraman and Ramanurthy, 2019). Despite this, healthcare professionals with stringent prescribing budgets frequently provide dietary modification guidance as a first line treatment for diagnosed malnutrition (Stange et al., 2013; Parsons et al., 2017). Dietary modification interventions can reduce voluntary food intake and elderly hospital patients reject up to 37.7% of each meal provided, leaving them at a nutritional deficit (Simzari et al., 2017). Comparatively, supplementing with ONS has shown no reduction in voluntary food intake over a 12-week period (Stange et al., 2013). CG32 states that care should be taken if advising dietary modification as it can supplement energy and protein intake without providing adequate micronutrients, potentially still leaving the patient at risk of malnutrition (NICE, 2006).
Evidence supports dietary modification techniques when patients are diagnosed using a validated screening tool as ‘low risk’ of malnutrition (Baldwin and Weekes, 2011). There is limited evidence for patients at ‘medium’ or ‘high’ risk and there is no evidence available for the long-term sustainability of a dietary modification plan (Baldwin and Weekes, 2011). Short-term nursing home intervention studies that used similar methodologies have reported conflicting findings. Odlund et al., (2003) (n=35), found that dietary modification can be an effective way to improve patient’s caloric intake by up to 30%. However, Smoliner et al., (2008) (n=65), found that nutritional requirements were already met by the nursing home approved meals and dietary modification had no effect on nutritional intake and provided little additional micronutrients. A third nursing home study (n=36), showed that even when portions were constructed by nursing home staff, dietary modification had no effect on voluntary nutritional intake when compared to the normal food menu (Baldwin et al., 2015). When combined with ONS, dietary modification led to significantly increased nutrient intake (p=0.018), although the majority of extra nutrition was provided by the ONS rather than additional food (Baldwin et al., 2015). In another 12-week nursing home study (n=104), a direct comparison and analysis of the effect of ONS against dietary modification was completed (Parsons et al., 2017). Daily caloric intake had a significant increase of 423kcal (p<0.001) and quality of life was rated significantly higher (p=0.002) in the ONS group when compared to the dietary modification group (Parsons et a.l, 2017). The discrepancies in findings shown above are not uncommon in community-based research due to small sample sizes and uncontrolled, variable environments (Odlund et al., 2003; Smoliner et al., 2008; Baldwin et al., 2015; Parsons et al., 2017). Furthermore, findings from these studies cannot be extrapolated to community patients outside of nursing homes because, during the intervention residents were served meals by care home staff. Community patients often have reduced mobility and limited practical help and there was no report on the feasibility of patients making dietary modifications outside of a care environment (Odlund et al., 2003). There is one systematic review that evaluated the effects of dietary modification across different care settings and results showed that caloric and protein intake was improved when diet was modified (Morilla-Herrera et al., 2016). However, due to poor methodological quality of the included studies, only 4 trials were analysed, and further research was needed to make any conclusions on the effectiveness of dietary modification (Morilla-Herrera et al., 2016). Research using robust methodology and outcome measures but completed across all settings would be beneficial for an overall assessment of the effectiveness of dietary modification. Although the majority of evidence fails to build an integrated picture of the overall effectiveness of ONS, there are 2 pieces of research that included various patient groups and care settings that can be applied to all patients. Firstly, Cawood, Elia and Stratton (2012), conducted a systematic review on the effectiveness of high-protein ONS that found significant reductions in complications (p<0.001), reduced hospital readmissions (p=0.004), improved grip strength (p=0.014), increased nutritional intake (p<0.001) and improved weight (p<0.001). Secondly, in 2007 a ‘review of reviews’ was published by Stratton and Elia (Stratton and Elia, 2007). Upon publication, it was arguably the most influential paper for the field as it assessed all existing systematic reviews on the evidence for ONS. It was found that the conclusions drawn from the analysed reviews were largely consistent, showing improved functional, clinical and nutritional benefits when supplementing with ONS for malnutrition. Stratton and Elia’s review is commonly used in evidence summaries for ONS and informs several guidelines including CG32 (Stratton and Elia, 2007; NICE, 2006). However, the cut off point for this research was August 2006, meaning there is a need for an updated review of the evidence for ONS. To build a comprehensive picture of the evidence for the effectiveness of ONS, this review will build on the strengths of Cawood, Elia & Stratton’s high protein ONS review (2012) and Stratton & Elia’s ‘review of reviews’ (2007). Both reviews discussed dietary modification and compliance, which was appropriate as these topics are relevant to the subject area. However, these factors are known to give an incomplete picture of the effectiveness of ONS. This review will evaluate studies where ONS were prescribed and consumed by patients for the management of malnutrition and exclude trials where compliance was low or where dietary modification was provided alongside ONS. Cawood, Elia and Stratton (2012) demonstrated thorough methodology and analysis for high protein ONS; this review will adopt similar methodology to evaluate all types of ONS without limiting to high protein. Stratton & Elia (2007), reviewed the widest range of useful evidence up to 2006; this review will collect evidence from 2007-2019 to provide a current look at the evidence for ONS. This will be the only current analysis reporting on all patients, in all clinical settings and all patient outcomes. This will provide general effectiveness information for industry and healthcare professionals.
A systematic review and meta-analysis will be undertaken to evaluate the effectiveness of ONS for the management of malnutrition. Databases used to identify evidence to review will be: the Bath Spa University online library, Science Direct, Cochrane database, PubMed and Google Scholar. Reference lists will be searched and experts in the field of medical nutrition will be consulted. Search terms will be used both in isolation and combination. They will include: “sip”, “adult”, “nutrition”, “oral nutritional supplement”, “ONS”, “nutrition support”, “enteral”, “effectiveness”. If other search terms are used, they will be documented along with the results of the search. The study type to be included is RCTs as they are considered high quality research and similar methodologies used by RCTs will allow for more comparable data. RCTs in all care settings will be included. Studies will include participants prescribed ONS for malnutrition (diagnosed using a validated screening tool), Subjects eligible for inclusion will be: malnourished adults that are able to able to give informed consent and eat/drink safely. The exclusion criteria will be: paediatric studies, animal studies, healthy patients, patients receiving palliative care, patients already on a prescription for ONS and patients unable to provide informed consent.
For a review of this nature it is customary to collect research over a 10-year period (Smith et al., 2011). However, this paper aims to fill the research gap that was left by Stratton and Elia’s review (2007). Therefore, this review will collect evidence from 2007-2019. Titles and abstracts will be examined to check the research is relevant and meets the inclusion criteria for this review. Duplicates from each database will be excluded. All papers will be peer-reviewed and will be given a quality rating score using the CASP Checklist for Randomised Controlled Trials (CASP, 2018). Any trials that have major limitations highlighted by the quality assessment will be excluded.
All patient outcomes reported in the included RCTs will be analysed. Outcome measures will be analysed individually and within the categories of ‘functional’, ‘nutritional’ and ‘clinical’. The meta-analysis of results will be completed using R Commander and varying data types will be analysed accordingly (R Commander, 2019). All data will be presented graphically using forest plots and bar charts to report on the findings of each RCT. Categorical data will be presented as odds ratio (OR) and 95% confidence intervals (CI) or relative risk (RR) and 95% CI. Continuous data will use a fixed-effects model with results being expressed as weighted mean differences and 95% CI. A generalised linear model (GLM) or a linear model (LM) will be used where appropriate to investigate the relationships of the effects of ONS on the outcome measures. The precise methods of statistical analysis will depend on the data that is collected.
Ethics and risk
Although no study can be completed without consideration of ethics, this review will not include primary research or human participants so no there are no immediate ethical concerns. The quality assessment checklist detailed in the methodology will ensure that no studies that broke ethics will be included. Because the review is research-based, there is no risk to others and minimal risk for the researcher. Harm could arise from poor working conditions and desk posture, eye strain from prolonged use of a computer screen and stress-related illness. To minimise this risk, care will be taken to follow guidelines for office workers that include taking regular breaks and using a computer monitor screen rather than a laptop to ensure correct posture (Health and Safety Executive, 2019). There is further risk of work being lost due to human error, technological or mechanical breakdown, this is addressed fully in the following contingency and project managment section.
Contingency and project management
Careful planning will be required to execute the project detailed above. When the systematic search is completed, the number of RCTs that fit the inclusion criteria may be too large to analyse. Extensive data will be collected about each study (e.g. outcome measures, patient groups, study location) found in the systematic search so that, if there are too many matching trials, the research question can be reframed based on common themes between trials. A similar review may be found during the search that would reduce the usefulness of this review. To minimise this risk, the NIHR Prospero database was checked for similar registered systematic reviews and care was taken to search all existing evidence (NIHR, 2019). If a similar review is identified during the search, the research will be re-framed to meet the current research need by looking at further recommendations of other reviews.
The final consideration is time management. Personal situations such as the onset of illness or technical drawbacks, such as data not saving correctly, could have an impact on the timing of this project. Reasonable care will be taken to stay in good health for the duration of this project and all work will be stored on online systems to ensure work is saved in the event of computer loss/damage/theft. A Gaant chart has been developed to ensure appropriate project time management (see appendix) (Smartsheet, 2019). Each month has been allocated a main task with subtasks. The systematic search, data collection and meta analysis will be completed in November. In December, the first half of the paper (up to the results section) will be written and sections will be submitted to the dissertation supervisor for feedback. January will be dedicated to writing the results, discussion and conclusion. From February until May, the paper will be redrafted and made ready for submission on May 15th, 2020. A visual graph of overlap between each task was also generated although due to the size of the document it has not been included in the proposal. Visual representation is not imperative to understand the timeline. The Gantt chart is a proposed schedule and it is expected that as the research develops it be altered; periods of contingency time have been allocated regularly to allow for any unforeseeable changes.
Baldwin, C. and Weekes, C.E. (2011) ‘Dietary advice with or without oral nutritional supplements for disease-related malnutrition in adults’, Cochrane Database of Systematic Reviews, 7(9). doi:10.1002/14651858.CD002008.
Baldwin, C., Moore, K., Steele, C., Young, C., Araki, I., Dudhiya, N., Gilson, A. and Majundar, A. (2015) ‘The effect of food fortification with or without oral nutritional supplements on energy and protein provision and intake in nursing home residents: a service evaluation’, Clinical Nutrition ESPEN. 10(5) pp. e188-e189. doi:10.1016/j.clnesp.2015.03.029.
BAPEN (2003) The ‘MUST’ report: nutritional screening for adults: a multidisciplinary responsibility. Development and use of the Malnutrition Universal Screening Tool (‘MUST’) for adults. Redditch: BAPEN.
BAPEN (2019) ‘MUST’ Online Calculator. Available at: https://www.bapen.org.uk/screening-and-must/must-calculator. (Accessed: 01/11/2019).
Brotherton, A., Simmonds, N. and Stroud, M. (2010) Malnutrition matters: meeting quality standards in nutritional care. Available at: https://www.bapen.org.uk/pdfs/toolkit-for-comissions.pdf. (Accessed: 19/10/2019)
Bruce, D., Laurance, I., McGuiness, M., Ridley, M. and Goldswain, P. (2003) ‘Nutritional supplements after hip fracture: poor compliance limits effectiveness’, Clinical Nutrition. 22(5) pp.497-500. doi:10.1016/s0261-5614(03)00050-5
CASP (2018). CASP Checklists. Available at: https://casp-uk.net/casp-tools-checklists/ (Accessed: 19/10/2019).
Cawood, A.L., Elia, M. and Stratton, R.J. (2012) 'Systematic review and meta-analysis of the effects of high protein oral nutritional supplements', Ageing Research Reviews, 11(2), pp. 278-296. doi:10.1016/j.arr.2011.12.008.
Elia, M. (2015) The cost of malnutrition in England and potential cost savings from nutrition interventions (full report). Available at: https://www.bapen.org.uk/pdfs/economic-report-full.pdf. (Accessed: 19/10/2019)
Elia, M. and Russell, C.A. (2009) Combating malnutrition: recommendations for action. Report from the Advisory Group on Malnutrition. Redditch: BAPEN.
Elia, M. and Stratton, R.J (2009) Calculating the cost of disease-related malnutrition in the UK in 2007 (public expenditure only). Combating Malnutrition: Recommendations for Action. Redditch: BAPEN.
Gandy, J. (2019). Manual of Dietetic Practice. 6th edn. Chichester: Wiley Blackwell.
Health and Safety Executive (2019). Office health and safety. Available at: http://www.hse.gov.uk/office/. (Accessed: 20/10/2019).
Hubbard, G.P., Elia, M., Holdoway, A. and Stratton, R.J. (2012) ‘A systematic review of compliance to oral nutritional supplements’, Clinical Nutrition, 31(3), pp. 293-312, doi:10.1016/j.clnu.2011.11.020.
Jobse, L., Liao, Y., Bartram, M., Delantonio, K., Uter, W., Stehle, P., Sieber C.C. and Volkert, D. (2015) ‘Compliance of nursing home residents with a nutrient- and energy-dense oral nutritional supplement determines effects on nutritional status’, Journal of Nutrition, Health & Aging, 19:3, pp. 356-64. doi:10.1007/s12603-014-0544-y.
Lad, H., Gott, M. and Gariballa, S. (2005). ‘Elderly patients’ compliance and elderly patients’ and health professionals’ views and attitudes towards prescribed sip-feed supplements’, Journal of Nutrition, Health & Aging, 9(5), pp. 310–314
Lawson, R.M., Doshi, M.K., Ingoe, L.E., Colligan, J.M., Barton, J.R. and Cobden, I. (2000) ‘Compliance of orthopaedic patients with postoperative oral nutritional supplementation’, Clinical Nutrition. 19(3), pp.171-5. doi:10.1054/clnu.1999.0094
Lovesley, D., Parasuraman, R. and Ramanurthy, A. (2019) ‘Combating hospital malnutrition: dietitian-led quality improvement initiative’, Clinical Nutrition, 30(1), pp. 19-25. doi:10.1016/j.clnesp.2019.02.011
Liljeberg, E., Andersson, A., Blom Malmberg, K. and Nydahl, M. (2019) ‘High adherence to oral nutritional supplements prescribed by dietitians: a cross-sectional study on hospital outcomes’, Nutrition in Clinical Practice, 00(0), pp. 1-12. doi:10.1002/ncp.10243
Meijers, J.M., Halfens, R.J., Wilson, L. and Schols J.M. (2012) 'Estimating the costs associated with malnutrition in Dutch nursing homes', Clinical Nutrition, 31(1), pp. 65-68. doi: 10.1016/j.clnu.2011.08.009.
Morilla-Herrera, J.C., Martin-Santos, F.J., Caro-Baustista, J., Saucedo-Figueredo, C., Garcia-Mayor, S. and Morales-Ascenscio, J.M. (2016) ‘Effectiveness of food-based fortification in older people. A systematic review and meta-analysis’, Journal of Nutrition, Health & Aging. 20(2) pp. 178-184. doi: 10.1007/s12603-015-0591-z.
Morley, J.E. (2017) ‘Anorexia of ageing: a key component in the pathogenesis of both sarcopenia and cachexia’, Journal of Cachexia, Sarcopenia and Muscle. 8(4), pp. 523-526. doi: 10.1002/jcsm.12192
NICE (2006) Nutrition support in adults: oral nutrition support, enteral tube feeding and parenteral nutrition. Clinical guideline 32. Available at: https://www.nice.org.uk/guidance/cg32 (Accessed: 15/10/2019).
NICE (2019). Nutrition support in adults: oral nutrition support, enteral tube feeding and parenteral nutrition. Clinical guideline 32 evidence. Available at: https://www.nice.org.uk/guidance/cg32/evidence (Accessed: 19/10/2019).
NIHR (2019). PROSPERO International prospective register of systematic reviews. Available at: https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=14546. (Accessed: 19/10/2019).
Odlund, O.A., Armyr, I., Soop, M., Jerstrom, S., Classon, I., Cederholm, T., Ljungren, G. and Ljunguist, O. (2003) ‘Energy-dense meals improve energy intake in elderly residents in a nursing home’, Clinical Nutrition. 22(2), pp. 125-131. doi:10.1054/clnu.2002.0610
Parsons, E.L., Stratton, R.J., Cawood, A.L., Smith, T. and Elia, M. (2017) ‘Oral nutritional supplements in a randomised trial are more effective than dietary advice at improving quality of life in malnourished care home residents’, Clinical Nutrition, 36(1), pp. 134-142. doi:10.1016/j.clnu.2016.01.002.
R Commander (2017) R: a language and environment for statistical computing. V.3.4.2 [Computer program]. Available at: https://www.rcommander.com/ (Accessed: 05/11/2019)
Russell, C.A and Elia, M. (2014) Nutrition screening surveys in hospitals in the UK, 2007-2011: a report based on the amalgamated data from the four nutrition screening week surveys undertaken by BAPEN in 2007, 2008, 2010 and 2011. Available at: http://www.bapen.org.uk/pdfs/nsw/bapen-nsw-uk.pdf (Accessed: 15/10/2019).
Russell, C.A and Elia, M. (2015) Nutrition screening surveys in care homes in the UK: a report based on the amalgamated data from the four nutrition screening week surveys undertaken by BAPEN in 2007, 2008, 2010 and 2011. Available at: http://www.bapen.org.uk/pdfs/nsw/care-homes/care-homes-uk.pdf (Accessed: 15/10/2019).
Saunders, J. and Smith, T. (2010) 'Clinical Medicine', Journal of the Royal College of Physicians of London, 10(6), pp. 624-627. doi:10.7861/clinmedicine.10-6-624
Simzari, K., Vahabzadeh, D., Nouri Saeidlow, S., Koshbin, S. and Bektas, Y. (2017). ‘Food intake, plate waste and its association with malnutrition in hospitalized patients’, Nutricion Hospitalaria. 34(5), pp. 1376-1381. doi 10.20960/nh.1102.
Smartsheet (2019). Smartsheet. Available at: https://www.smartsheet.com/customers-home. (Accessed: 19/10/2019).
Smith, V., Devance, D., Begley, C.M. and Clarke, M. (2011) ‘Methodology in conducting a systematic review of systematic reviews of healthcare interventions’, BMC Medical Research Methodology, 11(1), doi:10.1186/1471-2288-11-15.
Smoliner, C., Norman, K., Scheufele, R., Hartig, W., Pirlich, M. and Lochs, H. (2008) ‘Effects of food fortification on nutritional and functional status in frail elderly nursing home residents at risk of malnutrition’, Nutrition. 24(11-12), pp. 1139-1144. doi:10.1016/j.nut.2008.06.024.
Stange, I., Bartram, M., Liao, Y., Poeschl, K., Kolpatzik, S., Uter, W., Siber, C.C., Stehle, P. and Volkert, D. (2013) ‘Effects of a low-volume, nutrient- and energy-dense oral nutritional supplement on nutritional and functional status: a randomised, controlled trial in nursing home residents’, Journal of the American Medical Directors Association, 14(8), pp. 628.e1-628.e8. doi:10.1016/j.jamda.2013.05.011.
Stratton, R.J., Hackston, A., Longmore, D., Dixon, R., Price, S., Stroud, M., King, C. and Elia, M. (2004). ‘Malnutrition in hospital outpatients: prevalence, concurrent validity and ease of use of the ‘malnutrition universal screening tool (‘MUST’) for adults’, British Journal of Nutrition. 92(5), pp. 799-808. doi: 10.1079/bjn20041258
Stratton, R.J. and Elia, M. (2007) ‘A review of reviews: a new look at the evidence for oral nutritional supplements in clinical practice’, Clinical Nutrition Supplements, 2(1), pp. 5-23. doi:10.1016/j.clnu.2007.04.004.
Stratton, R.J., Green, C.J. and Elia, M. (2003). Disease related malnutrition: an evidence-based approach to treatment. Oxford: Cabi Publishing.
WHO (2003) Adherence to long-term therapies: evidence for action. Edited by E. Sabate. Geneva: World Health Organisation.