Grades are shown as the source states them. WHO grades recommendations as strong or conditional with evidence quality from high to very low. The GLIM criteria are an expert consensus without grades.
Key recommendations
Take two steps: first screen with any validated tool to find people at risk, then assess those at risk to diagnose malnutrition and grade its severity.
A two-step model for risk screening and diagnosis assessmentGlobal Leadership Initiative on Malnutrition (GLIM) 2019
Diagnose malnutrition when at least one phenotypic criterion (weight loss, low BMI or reduced muscle mass) and at least one aetiological criterion (reduced food intake or assimilation, or inflammation or disease burden) are present.
Table 3Global Leadership Initiative on Malnutrition (GLIM) 2019
Give older people with undernutrition oral supplemental nutrition together with dietary advice; it reduces mortality and improves weight gain.
Strong; moderate-quality evidenceRecommendation 2World Health Organization (WHO) 2017
Encourage every older person, including those at risk of or affected by undernutrition, to eat a healthy diet with enough energy, protein and micronutrients.
3.1.2 Malnutrition: considerationsWorld Health Organization (WHO) 2017
For declining physical capacity (measured by gait speed, grip strength or other performance tests), recommend multimodal exercise including progressive resistance training.
Strong; moderate-quality evidenceRecommendation 1World Health Organization (WHO) 2017
Diagnosis
Phenotypic thresholds: weight loss of more than 5% in the past 6 months or more than 10% over a longer period; BMI below 20 kg/m² under age 70 or below 22 at 70 and over (in Asia, below 18.5 and below 20); or reduced muscle mass on a validated body-composition measure.
Table 3Global Leadership Initiative on Malnutrition (GLIM) 2019
Aetiological criteria: intake at or below 50% of energy requirement for more than a week, any reduction for more than 2 weeks, or a chronic gastrointestinal condition impairing absorption; or inflammation from acute illness or injury or from chronic disease such as heart failure, COPD, rheumatoid arthritis, kidney or liver disease or cancer.
Table 3; Reduced food intake; Disease burden/inflammationGlobal Leadership Initiative on Malnutrition (GLIM) 2019
Severity: stage 1 (moderate) with weight loss of 5–10% in 6 months or 10–20% over longer, or BMI below 20 (under 70) or 22 (70 and over); stage 2 (severe) with weight loss above 10% in 6 months or above 20% over longer, or BMI below 18.5 (under 70) or 20 (70 and over).
Table 4Global Leadership Initiative on Malnutrition (GLIM) 2019
Classify by cause: chronic disease with inflammation, chronic disease with little or no inflammation, acute illness or injury with severe inflammation, or starvation from hunger or food shortage.
Table 5Global Leadership Initiative on Malnutrition (GLIM) 2019
Investigations
A nutritional assessment covers the dietary history, food records or 24-hour recall, examination for signs of poor nutrition, laboratory tests where useful, and muscle mass and strength.
3.1.2 Malnutrition: considerationsWorld Health Organization (WHO) 2017
Weigh people repeatedly over time to see whether weight is falling, stable or recovering; many have already lost a lot of weight by the time they present.
Weight lossGlobal Leadership Initiative on Malnutrition (GLIM) 2019
Measure muscle mass with DXA, bioimpedance, ultrasound, CT or MRI where available; otherwise use calf or mid-arm circumference, with grip strength as a supporting measure. Thresholds for Asian populations (AWGS) for appendicular skeletal muscle index are below 7.0 kg/m² in men and below 5.4 (DXA) or 5.7 (bioimpedance) in women.
Reduced muscle mass; Table 2Global Leadership Initiative on Malnutrition (GLIM) 2019
CRP, albumin or prealbumin can support a judgement about inflammation.
Disease burden/inflammationGlobal Leadership Initiative on Malnutrition (GLIM) 2019
Treatment
Oral supplemental nutrition means extra high-quality protein and calories with adequate vitamins and minerals, tailored after assessment by a trained professional and given as supplements, nutrient-rich foods or special formulations — always alongside dietary advice.
3.1.2 Malnutrition: Box 2; rationaleWorld Health Organization (WHO) 2017
Consider specially formulated supplementary foods (ready-to-eat or milled) with adjusted energy, protein, fat or micronutrient content.
3.1.2 Malnutrition: considerationsWorld Health Organization (WHO) 2017
Mealtime interventions such as family-style meals or social dining help, especially for people who live alone or are socially isolated.
3.1.2 Malnutrition: considerationsWorld Health Organization (WHO) 2017
Use the aetiological criteria to guide what intervention is needed and what outcome to expect.
Approach to using combined criteriaGlobal Leadership Initiative on Malnutrition (GLIM) 2019
Important geriatric considerations
Reduced taste and smell, poor oral health, isolation, loneliness and depression all raise the risk of malnutrition. After 60, lean mass falls while fat mass rises, so a stable weight can hide muscle loss.
3.1.2 MalnutritionWorld Health Organization (WHO) 2017
Protein absorption falls with age and standard protein intakes may not be enough; low protein intake raises the risk of sarcopenia, osteoporosis and impaired immunity.
3.1.2 Malnutrition; considerationsWorld Health Organization (WHO) 2017
Reduced intake can come from poor oral health, medicine side effects, depression, dysphagia and gastrointestinal symptoms such as nausea, vomiting, diarrhoea, constipation or abdominal pain.
Reduced food intake or assimilationGlobal Leadership Initiative on Malnutrition (GLIM) 2019
Side effects of supplements are mostly gastrointestinal (nausea, diarrhoea) and more frequent in hospital; WHO judged the risks small.
3.1.2 Malnutrition: rationaleWorld Health Organization (WHO) 2017
Drug doses
Not covered in this summary — see the original guideline.
When to refer
Supplementation should be tailored to the person's needs as assessed by a trained health care professional.
3.1.2 Malnutrition: Box 2World Health Organization (WHO) 2017
Red flags
Refer for medical review when there are signs of serious underlying illness: gross cachexia, rapid weight loss, obstruction or difficulty swallowing, vomiting, chronic diarrhoea, or abdominal pain or swelling.
3.1.2 Malnutrition: considerationsWorld Health Organization (WHO) 2017
Recent updates
The GLIM criteria (2019) were designed as a global standard for diagnosing malnutrition, with a plan to revisit them every 3–5 years and further work needed on muscle mass and BMI thresholds for Asian populations.
Abstract; Low BMIGlobal Leadership Initiative on Malnutrition (GLIM) 2019