The MNA® is a reliable and easy-to-use nutritional assessment tool. It was developed to assess nutrition status as part of the standard evaluation of elderly patients age 65 years and older.
The MNA® was initially validated for early detection on protein-energy malnutrition in the elderly in three successive studies on more than 600 subjects that were conducted in France and the United States from 1991 – 1993.
The first study, conducted in Toulouse in 1991, included a cohort of 155 elderly subjects. Subsequently, the MNA® was validated in 1993 in a population of 347 home-living elderly people in the New Mexico Ageing Process Study (NMAPS), a longitudinal survey on nutrition and aging. A shortened form, the MNA®-SF, was validated in another cohort of 120 elderly persons in Toulouse in 1993.
The validation studies focused on the accuracy and effectiveness of the MNA as these are the major requirements for a screening test to be considered effective.
The two assessments were compared to the MNA® score using descriptive statistics, principal component analysis and discriminant analysis. Clinical status was considered the gold standard.
The study results showed a strong correlation between the MNA® and biochemical nutritional parameters (p < .0001 for albumin).
Cross tabulation of the MNA® score and serum albumin concentrations determined clearly defined thresholds to classify nutritional status. This scale could distinguish between elderly patients with adequate nutritional status, protein-calorie malnutrition, or risk of malnutrition. With this scoring, sensitivity was found to be 96%, specificity was 98%, and predictive value 97%.
Even in a healthy aging population, the MNA® could definitely classify 70-75% of elderly patients as normal or undernourished without biochemical indices; more importantly, the MNA® identified the remaining 25-30% as at-risk before changes in weight or albumin levels occurred. These individuals are more likely to have a decrease in caloric intake that can be easily corrected by nutritional intervention.
The results also revealed the MNA was strongly correlated to dietary intakes (p < .05 for energy and other nutrients) and anthropometric parameters (p < 0.0001 for BMI). Furthermore, the MNA® scale was predictive of mortality and hospital costs. Together, the results establish the strong capacity of the MNA to reflect the nutritional status and the risk of malnutrition in the elderly.
Currently, more than 100 published studies support the sensitivity, specificity, and reliability of the MNA® in different settings and countries.
In both medical practice and clinical research, the MNA® is by far the most widely used and validated tool for nutritional screening and assessment of the elderly.
