Mini Nutritional Assessment — components, scoring and interpretation

Mini Nutritional Assessment — components, scoring and interpretation

The Mini Nutritional Assessment (MNA) was developed specifically to assess malnutrition in elderly populations. The full MNA is a multidimensional tool identifying older people who are malnourished or at risk, whatever the cause; a short form (MNA-SF) has similar performance, and a six-item version has equivalent predictive value.

Structure: the MNA-SF is a 6-item screening section scored out of 14 points. If screening is abnormal, the full MNA (total 30 points) is completed with additional assessment items covering living situation, medication, pressure sores, meal frequency, protein and fluid intake, self-perceived health and nutrition, and mid-arm and calf circumference.

The six screening components (A–F): A — Food intake decline over the past 3 months due to loss of appetite, digestive problems, or chewing/swallowing difficulty: 0 = severe decrease, 1 = moderate decrease, 2 = no decrease. B — Weight loss in the last 3 months: 0 = >3 kg, 1 = does not know, 2 = 1–3 kg, 3 = no weight loss. C — Mobility: 0 = bed or chair bound, 1 = able to get out of bed/chair but does not go out, 2 = goes out. D — Psychological stress or acute disease in the past 3 months: 0 = yes, 2 = no. E — Neuropsychological problems: 0 = severe dementia or depression, 1 = mild dementia, 2 = no psychological problems. F1 — Body mass index: 0 = BMI <19; 1 = 19 to <21; 2 = 21 to <23; 3 = BMI ≥23. F2 — Calf circumference (used only if BMI is not available): 0 = CC <31 cm; 3 = CC ≥31 cm. Do not answer F2 if F1 has already been completed.

Interpretation of the screening score (maximum 14 points): 12–14 points — normal nutritional status (no further assessment needed). 8–11 points — at risk of malnutrition. 0–7 points — malnourished.

Action: a screening score of 11 or below indicates possible malnutrition and the full MNA should be completed; Essentials notes that where greater specificity is desired, a threshold of 10 or below may be used.

Performance: the MNA is 96% sensitive and 60% specific for body weight loss. Subjects with a normal baseline score had a lower mortality risk of 0.35 (95% CI 0.18–0.66) than those with an abnormal score.

Prognostic value: those judged at risk by the MNA had more frequent acute illness, greater need for assistance and more weight loss. The MNA is a powerful prognostic factor across several pathologies, particularly cancer, and can be used to assess cancer cachexia.

Advantages: designed for and validated in older people; non-invasive, needs no blood tests; usable by nurses in wards, clinics and long-term care; incorporates cognitive, psychological and mobility domains that other tools omit; and offers calf circumference as a substitute when BMI cannot be measured — a decisive practical advantage in bed-bound, kyphotic or amputee patients.

Disadvantages: specificity is only 60%, so it over-identifies risk; it requires cognitive cooperation and is difficult in severe dementia; the acute-illness item may score positively for reasons unrelated to nutrition; and it is a screening tool, not a diagnosis — it does not establish the cause.