can also be obtained without weight loss.39 The data suggest that improvements in comorbid conditions can be enhanced with lifestyle changes but that the effect is independent of whether weight loss occurs.
Weight loss, a hallmark of malnutrition
Weight loss, particularly if unintentional, should be first interpreted as a sign of malnutrition. Malnutrition is a complex syndrome with different clinical presentations. After screening for malnutrition, diagnosing malnutrition according to the GLIM consensus is based on recognising etiological and phenotypic criteria (see Table 14.1).40 Etiological factors include decreased dietary intake or assimilation, or inflammation. Phenotypic criteria are weight loss >5% within the past six months or >10% beyond six months, or low BMI. Diagnosing malnutrition based on low BMI without identifying a cause of malnutrition may overestimate the prevalence of malnutrition.
The spectrum of clinical presentations can be categorized according to the level of inflammation markers (see Table 14.1). Starvation or malnutrition due to reduced food intake or assimilation is observed with C‐reactive protein (CRP, mg L–) <3 mg L–1. Low‐medium intensity inflammation is described as inflammageing but was not shown to be associated with a decrease in body mass. Inflammageing can be classified as inadequate nutrition leading to increased risk for diseases associated with ageing.41 Conditions associated with medium inflammation lead to chronic malnutrition, called cachexia. Finally, high‐level inflammation associated with severe sepsis or trauma induces malnutrition with hypercatabolism (see Figure 14.1).
Starvation
Simple starvation is caused by pure protein−energy deficiency. Starvation can be short‐term (fasting) or long‐term (chronic protein−energy undernutrition). Worldwide, starvation is most often caused by lack of food or inadequate food supply in relation to socioeconomic problems.
Older people ingest fewer calories than younger adults. On average, people over the age of 70 consume one‐third fewer calories than younger people.42 About 16−18% of community‐dwelling elderly people consume fewer than 1000 kcal daily.43 This reduction in intake places older adults at risk for protein−energy, vitamin, and mineral undernutrition.
In older subjects, anorexia is frequent: from 3.3% in the community to 33% in nursing homes.44 Starvation occurring in the presence of adequate food results from the inability to swallow, a non‐functioning gastrointestinal tract, or failure of appetite (anorexia). Upper‐tract pathology, particularly due to helicobacter pilory infection, and constipation may induce anorexia. Anorexia is more frequent with depression, need for assistance with shopping or cooking, masticatory or swallowing problems, and higher CRP.44 Anorexia may also result from changes in the physiological regulation of appetite and satiety as a physiological response to ageing.45 The importance of understanding this relationship lies in addressing pharmacological46 or dietary interventions47 that may reverse this anorexia of ageing. Few diseases or conditions lead to anorexia without inflammation. Among them, having difficulty with instrumental activities of daily living due to cognitive troubles is the most prevalent. Weight loss (>5% body weight) occurs twice as frequently in older people with Alzheimer’s disease.48 The association of basic activities of daily living dependence, oral health problems, and swallowing problems leads to a high prevalence of malnutrition.49
Table 14.1 Malnutrition criteria according to the GLIM consensus.
Source: Jensen et al.,40 © 2019, John Wiley and Sons.
| Table 3. Phenotypic and Etiologic Criteria for the Diagnosis of Malnutrition | ||||
|---|---|---|---|---|
| Phenotypic Criteriaa | Etiologic Criteriaa | |||
| Weight Loss(%) | Low Body Mass Index (kg/m2) | Reduced Muscle Massb | Reduced Food Intake or Assimilationc,d | Inflammatione,f,g |
| >5% With past 6 months, or >10% beyond 6 months | <20 if <70 years, or <22 if > 70 years | Reduced by validated body composition measuring techniquesb | ≤50% of ER > 1 week, or any reduced for > 2 weeks, or any chronic GI condition that adversely impacts food assimilation or absorptionc,d | Acute disease/injurye,g or chronic disease‐ relatedf,g |
| Asia: <18.5 if <70 years, or <20 if >70 years |
ER, energy requirements; GI, gastrointestinal.
a Requires at least 1 phenotypic criterion and 1 etiologic criterion for diagnosis of malnutrition.
b For example, fat‐free mass index (kg/m2) by dual‐energy absorptiometry or corresponding standard using body composition methods such as bioelectrical impedance analysis, computed tomography, or magnetic resonance imaging. When not available by regional preference, physical examination or standard anthropometric measures such as mid –arm muscle or calf circumferences may be used. Thresholds for reduced muscle mass need to be adapted to race (Asia). Functional assessment such as hand grip strength may be considered as a supportive measure.
c Consider gastrointestinal symptoms as supportive indicators that can impair food intake or absorption (e.g., dysphagia nausea, vomiting, diarrhea, constipation, or abdominal pain). Uses clinical judgement to discern severity based on the degree to which intake or absorption is impaired. Symptom intensity, frequency, and duration should be noted.
d Reduced assimilation of food /nutrients is associated with malabsorptive disorders such as short bowel syndrome, pancreatic insufficiency, and after bariatric surgery. It is also associated with disorders such as esophageal strictures, gastroparesis, and intestinal pseudo‐obstruction. Malabsorption is a clinical diagnosis manifest as chronic diarrhea or steatorrhea. Malabsorption in those with ostomies is evidenced by elevated volumes of output. Use clinical judgement or additional evaluation to discern severity based on frequency, duration, and quantitation of fecal fact and/or volumes of losses.
e Acute disease‐/injury‐related. Severe inflammation is likely to be associated with major infection, burns, trauma, or closed head injury. Other acute disease‐/injury‐related conditions are likely to be associated with mild to moderate inflammation.
f Chronic disease‐related. Severe inflammation is not generally associated with chronic disease conditions. Chronic disease conditions. Chronic or recurrent mild to moderate inflammation is likely to be associated with malignant disease, chronic obstructive pulmonary disease, congestive heart failure, chronic renal disease, or any disease with chronic or recurrent Inflammation. Note that transient inflammation of a mild degree does not meet the threshold for this etiologic criterion.
g C‐reactive protein may be used as a supportive laboratory measure.
