Linking Evidence Based Medicine to Geriatric Nutrition Screening The Mini Nutritional Assessment (MNA )

Transcription

1 Linking Evidence Based Medicine to Geriatric Nutrition Screening The Mini Nutritional Assessment (MNA ) by Janet Skates, MS, RD, LND, FADA, Nutrition Consulting Services, Kingsport, TN Patricia Anthony, MS, RD, Nestlé Nutrition, Vevey, Switzerland CPEU Sources of support: Nestlé Nutrition This article is reprinted with permission from the Indiana Dietetics in Health Care Communities dietetic practice group and Healthy Aging dietetic practice group. It originally appeared in the spring 2009 edition of The Spectrum, newsletter of Healthy Aging DPG and was updated and reprinted in the summer 2010 edition of The Hoosier, newsletter of the Indiana DHCC. Ó2009, The Spectrum Newsletter; Healthy Aging, a dietetic practice group of the American Dietetic Association. Used with permission. Ó2010, The Hoosier Newsletter; Indiana Dietitians in Health Care Communities, a state affiliate of the DHCC dietetic practice group of the American Dietetic Association. Used with permission. INTRODUCTION With the number of persons 65 years and older expected to double in coming decades, there is growing interest in the United States on containing healthcare costs for the elderly by increasing support to maintain them in community settings. The success of this shift in care depends on elders being able to maintain functional status. This occurs at a time when many older persons face failing health or other physiological or psychosocial changes that can lead to undernutrition. If undetected and untreated, progressive undernutrition can lead to malnutrition and cause loss of independence, lower quality of life, increased institutionalization, and death. This scenario presents opportunities for Registered Dietitians (RD) to demonstrate their value by designing effective nutrition programs that can help older Americans maintain or restore their nutrition status and maximize independent function. The first step is effective nutrition screening that quickly and accurately identifies those elders who are at risk for malnutrition so they can receive intervention early, when it is most effective. The causes of malnutrition in the aging population vary from physical reasons to social and psychological reasons that affect functionality (Table 1). Because each cause has a different treatment, screening tools should use multiple measures to detect specific causes of malnutrition. This article discusses the Mini Nutrition Assessment (MNA ), a nutrition screening tool developed specifically for persons 65 years and older, that helps the RD to target nutrition interventions to specific causes of malnutrition identified by specific questions in the MNA. Pinpointing the causes of malnutrition helps the RD make accurate nutrition diagnoses and implement early intervention, without wasting resources on those who need no intervention. DESCRIPTION AND USE The MNA is a nutrition screening tool that is specifically designed to identify malnutrition in the older adult age 65 and over. The MNA (Figure 1) focuses on six variables that together identify malnutrition in the elderly weight loss, body mass index (BMI) or calf circumference (CC), appetite, disease, dementia or depression, and immobility. The first three variables evaluate indicators of past nutrition status (weight loss), present nutrition status (BMI or CC) and potential future nutrition problems (appetite); the last three variables assess important age-related factors that negatively impact nutrition in the elderly (disease, dementia or depression, and immobility). Over time, the MNA has evolved in three steps - from the original full 18-item questionnaire to a two-step process, in which a shortened form of the MNA, the (MNA -SF), was used as a first step to screen out low-risk persons, to the recently revised MNA -SF, which can be used as a standalone tool to identify the malnourished, thereby shortening the time to accurately screen older adults and implement care. The original full MNA included 18 total questions and had a maximum combined total score of 30; a total score from 24 to 30 indicated adequate nutritional status, scores between 17 and 23.5 indicated risk for malnutrition, and scores less than 17 indicated malnutrition. However, the full MNA took too long for clinical use, so researchers introduced a short form of the MNA, made up of the 6 most strongly correlated questions from the original MNA. The MNA -SF preserved the accuracy and validity of the full MNA and saved time in screening out well nourished people. However, the 2-step process remained underutilized in clinical practice because the full MNA had to be completed to differentiate between those who were nutritionally at risk and those who were malnourished. Recently, the MNA -SF was revised and revalidated as a stand-alone screening tool. The new form incorporates 3 cut-off points, which allows clinicians to identify those who are malnourished without completing the full MNA. With a maximum score of 14, scores of indicate well nourished, scores of 8-11 indicate nutrition risk, and scores of 0-7 indicate malnourished. Unlike the original MNA -SF, the new form allows calf circumference to be substituted when BMI is not available. With the recent revisions, the new MNA -SF now facilitates screening in less than 5 minutes and makes the link to intervention easier. continued on page 16 WINTER 2011 CONNECTIONS - PAGE 15

2 continued from page 15 DEVELOPMENT AND VALIDATION OF THE MNA The original MNA was developed in the 1990 s and was validated in large representative samples of elderly persons worldwide. The tool was comprised of the items listed in Figure 1 plus biochemical markers and was compared with two criteria - clinical status and a battery of anthropometric, dietary, and biochemical indices (Table 2). Clinical status, as defined by a physician, was considered to be the gold standard to define malnutrition risk. The development study showed the MNA correlated strongly with conventional nutrition assessment (biochemical data, dietary intake, and anthropometric parameters) and also with clinical status. The MNA does not include laboratory data as exclusion of this information did not change the strength of the tool and thus makes it a more practical tool. The sensitivity, specificity, and positive predictive value according to clinical status were 96%, 98%, and 97% respectively. Additional validation studies among both frail and healthy older persons confirmed the usefulness of the MNA in clinical practice. The MNA agreed with physicians ratings of clinical status nearly 90% of the time. Even without laboratory data, the MNA correctly classified between 70% and 75% of all healthy and frail participants as normal or malnourished. The remaining 25% - 30% could not be definitely classified as either normal or malnourished; but were identified as at risk for malnutrition even before they lost weight or had changes in their serum albumin levels. This ability of the MNA to predict malnutrition before marked changes in weight or albumin level occur has proven to be a key benefit in clinical practice. The validity of the original MNA -SF was established by comparing it to the full MNA. Results showed the MNA - SF correlated strongly with the full MNA score and other nutritional parameters. Its high sensitivity and specificity, compared with the full MNA, indicated it was a valid screening tool. The recent revision and revalidation of the MNA -SF confirmed a strong correlation between the MNA and nutrition parameters, such as albumin and C-reactive protein. Statistical analysis showed the revised MNA -SF retains the validity and reliability of the original MNA in identifying elderly patients who were well-nourished, at-risk for malnutrition, or malnourished. Furthermore, in those patients for whom a BMI cannot be obtained, the study showed that calf circumference is an acceptable alternative. PAGE 16 - CONNECTIONS WINTER 2011 THE IDEAL SCREENING TOOL HOW DOES THE MNA MEASURE UP? The ideal nutrition screen may vary according to the targeted population, the care setting, and the purpose of the screening. While nutrition screening in a hospital is designed to identify patients who may benefit from nutritional support, screening tools in the community setting should be more focused on identifying individuals who are malnourished or nutritionally at risk. To be effective, the ideal screening tool should meet the criteria in Table 3. - The MNA is well validated and is supported by more than 400 published studies. In contrast, most nutrition screening tools in practice have not been validated. Why is validity important when selecting the best tool for screening a given population? Validated tools have proven they actually measure what they claim to measure in a specific population. By using validated tools, clinicians are more likely to correctly identify clients who truly need help, avoid missing those who need intervention, and begin intervention earlier when the potential for recovery is greater. They are less likely to waste resources on those who do not need intervention. Validated nutrition screening tools support evidence-based dietetics practice and facilitate decisionmaking based on the best available, valid, and relevant evidence. Validity is measured by sensitivity and specificity and by predictive value, which range from 0 100%. Sensitivity is the effectiveness of a test in detecting a disease in those who have the disease. The higher the sensitivity of a nutrition screening tool, the fewer true cases of nutrition risk go undetected. Specificity is the extent to which a test gives negative results in those that are free of the disease. The higher the specificity of a nutrition screening tool, the fewer well-nourished people are labeled as at nutrition risk.9 Positive predictive value is how many of the subjects who test positive truly have the disease. Negative predictive value is how many of the subjects who test negative truly do not have the disease. Ideally, a screening test should be highly sensitive and highly specific and have both positive predictive value and negative predictive value. Reliability is an important measure in assessing the accuracy of a nutritional screening tool. The tool should give the same results every time it is used. Inter-rater reliability measures the agreement between the results when more than one user applies it to the same subject. The MNA consistently demonstrates a high level of reliability. continued on page 17

3 continued from page 16 A nutrition screening tool should also provide an acceptable measurement of the condition being studied. A key determinant of reported prevalence of malnutrition is the cut-off level for body mass index (BMI) that defines malnutrition. The MNA s cut-point to define risk for malnutrition is BMI <22kg/m2, which has been shown to correctly identify clinical malnutrition in elderly patients with acceptable sensitivity and specificity. Lower BMI cut points for malnutrition, used in other screening tools, may be more reflective of the general population and not specifically geriatrics. This geriatric specific cut off may account for the higher reported prevalence of malnutrition with the MNA, which is consistent with a higher prevalence of nutrition issues in the geriatric vs. the general adult population. The ideal screening tool should be specific for the population that the tool is targeting. The MNA was specifically designed for the elderly and has been studied more than any other screening tool for older people.5 Screening tests should have clearly defined thresholds. Cross tabulation of the MNA score and serum albumin concentration in individuals without inflammation established thresholds that clearly distinguish those with adequate nutrition status vs. malnutrition vs. risk for malnutrition. Using albumin levels to establish the thresholds was appropriate as they are highly prognostic for morbidity and mortality in the elderly. Cut points for the revised MNA -SF were compared to those obtained with the full MNA. Results showed 80% correct classifications and no complete misclassifications when using BMI and 73% correct classification and no complete misclassifcations when using CC, confirming the validity of the MNA - SF s clearly defined thresholds. In today s environment, screening tests have to be quick and easy to use to be routinely incorporated into busy practice settings. The revised MNA is quick and requires no special skills or calculations, so nurses, dietitians, technicians, and other staff can easily complete the MNA screen in less than 5 minutes. A convenient table allows users to rapidly determine body mass index (BMI), eliminating the need to perform any calculations. Easy-to-follow directions for performing anthropometric measures, even in challenging patients such as those with amputations or who are bed-bound, are available in the user-friendly guidelines which are downloaded from the MNA website ( The MNA Website ( resources include MNA forms in more than 20 languages, interactive MNA forms, access to literature, guides to interpret the MNA, and suggested guidelines for intervention. The MNA is free to use and widely available for all practice settings. Because it does not rely on laboratory data, the MNA is ideal for community and ambulatory care settings, such as assisted living facilities and senior feeding programs, where resources for blood sampling may be limited or cost prohibitive. The ideal screening tool must be effective. Compared with other nutrition screening tools, the MNA is more likely to identify risk of developing undernutrition at an early stage so intervention can be started early when it is most effective. It is useful for follow-up and for monitoring the effectiveness of nutrition intervention. In recent studies, MNA scores improved in patients who received nutrition intervention after being identified by the MNA to have early malnutrition. The MNA predicts not only nutritional risk, but also outcomes of nutrition risk - functional problems, hospitalization, and mortality. Low MNA scores correlate with decline in functional ability, cognitive impairment, and increased frailty in older persons. In hospitalized patients, low MNA scores are predictive of adverse outcomes, including prolonged lengths of stay, increased frequency of discharges to a nursing home, and a nearly three-fold increase in mortality. CHALLENGES IN PRACTICE Because the MNA was specifically developed for use in persons over 65 years of age, it is not suitable as a universal screen for all ages and disease states. Completing the MNA may be challenging in cognitively impaired patients who can not provide reliable answers to the subjective questions about personal nutrition and general health. However, if a caregiver can provide accurate input and all questions on the form are answered, the MNA is considered the best tool to use for geriatric patients. In addition, the MNA was not designed for persons receiving enteral tube feedings; these high-risk patients should receive ongoing full nutrition assessment and follow-up by a R.D. NEW OPPORTUNITIES FOR USING THE MNA Although the MNA has been widely studied in research continued on page 18 WINTER 2011 CONNECTIONS - PAGE 17

4 continued from page 17 settings around the world, it has not been used as extensively in clinical practice in the US. It should be an essential component of every comprehensive geriatric assessment, along with the Mini Mental State Evaluation (MMSE), Geriatric Depression Scale, and Activities of Daily Living (ADLs). There is growing interest in using the MNA in long term residential care and sub-acute care facilities where malnutrition is extremely common and contributes to longer lengths of stays and more frequent readmissions to acute care. The sensitivity and specificity of the Minimum Data Set (MDS) trigger system has been problematic, and although the use of the MDS is mandatory in long term care, it follows that the concomitant use of a well-validated screen, such as the MNA -SF, to accurately identify malnutrition would strengthen the quality of nutrition care, reduce the risk of missing patients with malnutrition, and avoid wasting resources on those who are not at risk. Likewise, the phenomenal growth of the assisted living industry presents an unprecedented opportunity for using the MNA to screen for malnutrition. Unlike long term care and sub-acute care, the assisted living industry is largely unregulated and does not have mandated nutrition screening in place. More widespread use of the MNA would seemingly be welcomed in this setting where high value is placed on maintaining residents functional status to prevent transfer to more costly nursing home care. SUMMARY Malnutrition is a serious problem in many older adults that negatively impacts quality of life, functionality, and the ability to live independently. Many times malnutrition is reversible, and this calls for valid, effective screening tools to detect malnutrition. The MNA fulfills many criteria for an ideal screening tool for the elderly and is recommended by international organizations, including ESPEN and ADA s Evidence Analysis Library It provides a simple, noninvasive, inexpensive, easy-to-use nutrition screening tool that is highly specific, reliable, and well validated. The MNA can quickly and easily identify older adults (over 65 years of age) who are at risk for malnutrition. Among the nutrition screening and assessment tools available to the Registered Dietitian, the MNA must be regarded as the most established nutrition screening tool for the older population. Acknowledgement: The MNA was developed by the Nestlé Research Center, in collaboration with clinicians at the University of Toulouse, France and the University of New Mexico. It is the property of Nestlé S.A. continued on page 19 Perhaps the MNA s greatest potential is in screening and assessment of communityliving older individuals. Its proven ability to identity risk of developing undernutrition at an early stage fits well with the increased emphasis being given to prevention under Medicare and federal initiatives such as the Administration on Aging s home and community based long-term care programs that are designed to address the projected staggering increases in health care spending for aging boomers. Helping high-risk older adults avoid unnecessary placement in nursing homes by identifying and treating malnutrition risk early is consistent with AOA s long-range vision of having a long-term care service system that is person-centered, consumer-directed and helps people at risk of institutionalization to continue to live at home for as long as possible. NEW! You Spoke, We Listened Submitting Nominations for National Honors and Awards Just Got Easier! ADA is shining the spotlight on outstanding food and nutrition practitioners and supporters of the profession through its National Honors and Awards program. Don t miss this chance to honor those who have advanced the profession, exhibited leadership and shown devotion to serving others in both dietetics and allied fields. You may now submit your nominations entirely online! The submission deadline is midnight Central Standard Time on March 1, Award recipients will be announced in May 2011 and recognized at the ADA 2011 Food & Nutrition Conference & Expo in San Diego, CA. Visit our website to learn more and to submit your honors and awards nominations online: PAGE 18 - CONNECTIONS WINTER 2011

5 continued from page 18 Table 1. Effects of Aging on Nutrition Possible Changes with Aging Effect on Nutrition Sensory Impairment Decreased sense of taste Decreased sense of smell Loss of vision and hearing Oral health/dental problems Reduced appetite Reduced appetite Decreased ability to purchase and prepare food Difficulty chewing, inflammation, poor quality diet Change in energy needs Decreased physical activity Muscle loss (sarcopenia) Isolation / depression Financial constraints Diet lacking in essential nutrients Progressive depletion of LBM and loss of appetite Decreased functional ability, help needed with ADLs Decreased appetite Limited access to food; poor quality diet Cumulative Effect Progressive Undernutrition Reprinted with permission from the MNA website ( Table 2. Anthropometry Functional evaluation Dietary evaluation Clinical evaluation Biochemical markers Principle Criteria Used to Validate the MNA Weight, height, body mass index (BMI), mid-arm circumference (MAC), calf circumference (CC), mid-arm muscle circumference (MAMC), triceps skinfold (TSF), subscapular skin fold (SSF) Mini-Mental State Examination (MMSE), Activities of Daily Living (ADL), Instrumental Activities of Daily Living (IADL) Dietary history, 3-day food record, food-frequency questionnaire, Calculation of daily energy, fluid, macro- and micronutrient intake Clinical status including review of patients medical records Hematocrit, hemoglobin, full blood cell count and blood cell differentiation, total protein, albumin, prealbumin (transthyretin), transferrin, ceruloplasmin, retinol-binding protein, C-reactive protein, 1 -acid-glycoprotein, creatinine, cholesterol, triglycerides, -glutamyl transferase, vitamins A, B 1, B 2, B 6, B 12, D, E, folate, copper, zinc. Activation coefficients for vitamins B 1, B 2, and B 6. Adapted from: Guigoz Y, Vellas B, Garry PJ. Mini nutritional assessment : A practical assessment tool for grading the nutritional state of elderly patients. Facts Res Gerontol 1994;(Suppl 2): continued on page 20 WINTER 2011 CONNECTIONS - PAGE 19

6 continued from page 19 Table 3. Characteristics of Ideal Nutrition Screening Tool Valid and reliable scale in the intended population Minimal bias due to the data collector Accurate Clear definition of thresholds Easy to use and administer by available staff Low associated cost Relevant to outcomes Acceptable to patients Sensitive to change in score Adapted from: Thomas DR. Nutrition assessment in long-term care. Nutr Clin Pract. 2008;23: , and Gans KM, et al. Rate your plate: A dietary assessment and educational tool for blood cholesterol control. Nutrition in Clinical Care 2000;3: Selected References 1 Guigoz Y, Vellas B, Garry PJ. Mini Nutritional Assessment: a practical assessment tool for grading the nutritional state of elderly patients. Facts Res Gerontol 1994;(suppl 2): Vellas B, Guigoz Y, Garry PH, et al. The Mini Nutritional Assessment (MNA) and its use in grading the nutritional state of elderly patients. Nutrition 1999;15: Guigoz Y, Vellas B, Garry PJ. Assessing the nutritional status of the elderly: the Mini Nutritional Assessment as part of the geriatric evaluation. Nutr Rev 1996;54:S59-S65. 4 Kaiser MJ, Bauer JM, Rämasch C, et al. The short-form Mini Nutritional Assessment (MNA-SF): Can it be improved to facilitate clinical use? J Nutr Health Aging. 2009; 13(suppl 2): S16. 5 Thomas DR. Nutrition assessment in long-term care. Nutr Clin Pract. 2008;23: Gans KM, et al. Rate your plate: A dietary assessment and educational tool for blood cholesterol control. Nutrition in Clinical Care 2000;3: Guigoz Y. The Mini Nutritional Assessment (MNA ): review of the literature what does it tell us? J Nutr Health Aging. 2006;6: Bauer JM, Kaiser MJ, Anthony P, Guigoz Y, Sieber CC. The Mini Nutritional Assessment Its History, Today s Practice, and Future Perspectives. Nutr Clin Pract 2008;23: Weekes CE, Elia M, Emery PW. The development, validation and reliability of a nutrition screening tool based on the recommendations of the British Association for Parenteral and Enteral Nutrition (BAPEN). Clin Nutr. 2004;23: Persson MD, Hytter-Landahl A, Brismar K, Cederholm TE. Nutritional supplementation and dietary advice in geriatric patients at risk of malnutrition. Clin Nutr 2007;26: Donini LM, Savina C, Rosano A, et al. MNA predictive value in the follow-up of elderly patients. J Nutr Health Aging 2003;7: Kagansky N, Berner Y, Doren-Morag N, et al. Poor nutritional habits are predictors of poor outcomes in very old hospitalized patients. Am J Clin Nutri 2005;82: Thomas DR, et al. Malnutrition in sub-acute care. Am J Clin Nutri 2002;75: Kondrup J, Allison SP, Elia M, Vellas B, Plauth M. ESPEN guidelines for nutrition screening. Clin Nutr. 2002;22: American Dietetic Association Evidence Analysis Library. Unintended Weight Loss (UWL) in Older Adults: Nutrition Screening. Available at Accessed August 3, PAGE 20 - CONNECTIONS WINTER 2011 continued on page 21