Which patient is at the highest risk for malnutrition? Understanding vulnerable groups

October 5, 2025 •

5 min read

According to the World Health Organization, nearly 45% of deaths among children under 5 years of age are linked to undernutrition. While children are a particularly vulnerable group, the question of which patient is at the highest risk for malnutrition is complex and includes a wide range of individuals with specific medical conditions, social challenges, and physical limitations. Identifying these at-risk patients is the first step toward effective nutritional intervention and improved health outcomes.

Quick Summary

This article explores the patient populations facing the greatest risk of malnutrition, including those with chronic illnesses, hospitalized individuals, and the elderly. It details the physiological and social factors that contribute to nutritional deficiencies, outlining symptoms and diagnostic methods. Strategies for effective nutritional intervention and prevention are also discussed.

Key Points

Elderly patients are highly vulnerable: Advanced age, reduced appetite, and chronic health conditions place older adults, especially those institutionalized or isolated, at a significant risk for malnutrition.
Hospitalization exacerbates risk: Critical illness, surgery, and trauma create a hypermetabolic state, and many patients enter the hospital already malnourished, with their status declining further during their stay.
Cancer and cachexia are major threats: Patients with cancer, particularly in advanced stages or affecting the GI tract, face a high risk of cachexia driven by systemic inflammation and treatment side effects.
Chronic diseases impair nutrition: Inflammatory bowel diseases, chronic kidney disease, and liver disease interfere with nutrient absorption and metabolism, causing chronic malnutrition.
Early screening is crucial: Identifying at-risk patients promptly using validated screening tools like the MST or NRS 2002 enables early intervention, which is linked to better outcomes and reduced costs.
Socioeconomic factors play a role: Poverty, social isolation, and difficulty accessing nutritious foods are significant contributors to malnutrition, particularly in the elderly and chronically ill.
Neurological issues cause feeding difficulties: Patients with dementia, stroke, or Parkinson's disease often have trouble chewing and swallowing, compromising their ability to eat enough.

Understanding the Highest-Risk Patient Groups

Identifying the patient with the highest risk for malnutrition is not a one-size-fits-all diagnosis. Malnutrition is a multifaceted condition that can manifest as undernutrition, overnutrition, or micronutrient deficiencies, often driven by complex interactions between disease, social status, and physiology. While general risk factors like low income exist, certain patient populations face significantly elevated risks due to specific circumstances.

The Critically Ill and Hospitalized Patient

Hospitalization is a major risk factor for developing or worsening malnutrition. A significant percentage of patients are already malnourished upon admission, and for many, their nutritional status deteriorates further during their stay. A study in Lahore, Pakistan, found that almost 60% of hospitalized patients were undernourished.

Acute stress response: Critical illness, surgery, or trauma trigger a hypermetabolic state that increases the body's energy and protein demands. If nutritional intake does not meet these elevated needs, the patient's body breaks down muscle and fat for fuel, leading to cachexia and wasting.
Treatment side effects: Chemotherapy, radiation, and various medications can cause a loss of appetite, nausea, vomiting, or altered taste, significantly decreasing food intake.
Limited access to food: Bedridden patients or those with medical procedures may face delays or limitations in receiving meals. In some cases, frequent interruptions or unappealing hospital food can further discourage eating.

The Elderly and Geriatric Population

Older adults, especially those living alone, with limited mobility, or in long-term care, are highly susceptible to malnutrition. The reasons are often a combination of physiological, psychological, and social factors.

Physiological changes: The natural aging process can lead to a diminished sense of taste and smell, poor dentition, and decreased appetite (anorexia of aging). Swallowing difficulties (dysphagia) also become more common, making eating a challenge.
Chronic health conditions: Many older adults live with chronic diseases like diabetes, dementia, or cancer, which all interfere with nutrient intake or metabolism. Cognitive decline can also cause an individual to forget to eat or neglect their well-being.
Social and economic isolation: Living alone, having limited social support, or experiencing bereavement can lead to depression and a lack of motivation to prepare and eat meals. Financial constraints may also limit access to nutritious food.

Patients with Chronic and Advanced Diseases

Chronic diseases, particularly those involving high inflammation or affecting the digestive system, place patients in a constant state of nutritional vulnerability.

Cancer patients: Malnutrition is extremely common in oncology, with some studies showing up to 70% of cancer patients being malnourished or at risk. Cachexia, a profound muscle wasting syndrome driven by systemic inflammation, is a particular concern, especially in advanced stages or with cancers of the gastrointestinal tract and head and neck.
Gastrointestinal disorders: Conditions like Crohn's disease, ulcerative colitis, and celiac disease can cause malabsorption, chronic diarrhea, and pain, preventing the body from absorbing necessary nutrients. Pancreatic diseases can also lead to malabsorption.
Neurological conditions: Patients with dementia, stroke, or Parkinson's disease often face severe swallowing difficulties and reduced cognitive ability to self-feed, significantly elevating their malnutrition risk.

Comparison of High-Risk Patient Groups


Risk Factor Category	Elderly Patient	Critically Ill Patient	Cancer Patient	GI Disorder Patient
Primary Cause	Anorexia of aging, social isolation, chronic conditions	Hypermetabolism, trauma, surgery, treatment effects	Cancer cachexia, systemic inflammation, treatment side effects	Malabsorption, chronic diarrhea, pain
Immediate Onset Risk	Gradual decline over time, often unnoticed	Very high risk immediately upon admission, rapid onset	Increases with cancer stage and aggressive treatment	Varies based on chronicity and severity of the disease
Key Vulnerability	Poor appetite, dysphagia, social factors, financial issues	Acute metabolic stress, restricted oral intake, reduced mobility	Systemic inflammation, anorexia, treatment side effects	Impaired nutrient absorption, GI symptoms
Screening Tools	Mini Nutritional Assessment (MNA)	Nutrition Risk Screening (NRS 2002), NUTRIC score	Subjective Global Assessment (SGA), Patient-Generated SGA	Diet history, symptom assessment

Assessment and Intervention Strategies

For high-risk patients, early identification and a tailored nutritional plan are critical for recovery and improving outcomes.

Routine screening: Hospitals and care facilities should implement routine nutritional screening for all admissions. Validated tools like the Malnutrition Screening Tool (MST) or Nutritional Risk Screening 2002 (NRS 2002) are recommended to identify patients at risk within the first 24-48 hours.
Comprehensive assessment: Patients identified as at risk should receive a comprehensive nutritional assessment by a qualified professional, such as a registered dietitian. This includes detailed diet history, physical examination, anthropometric measurements (e.g., weight, BMI), and relevant lab tests.
Nutritional support: Intervention depends on the severity and cause of malnutrition. It may include nutritional counseling, fortified foods, oral nutritional supplements, or, in severe cases, enteral or parenteral nutrition. Critically ill patients may need prompt enteral feeding to maintain lean body mass.
Multidisciplinary care: Management of high-risk patients should involve a multidisciplinary team, including dietitians, doctors, nurses, and social workers, to address the complex medical, psychosocial, and functional factors impacting nutrition.

Conclusion: Prioritizing Nutrition for Positive Outcomes

While malnutrition affects millions worldwide, specific patient groups—including the elderly, the chronically ill (especially cancer and GI patients), and those in hospital settings—face a significantly higher risk. The highest-risk patient is often a composite of several factors, such as advanced age, multiple chronic conditions, social isolation, and exposure to the metabolic stress of acute illness or surgery. Early identification through routine screening, followed by a comprehensive nutritional assessment and targeted intervention, is vital for improving health outcomes, reducing complications, and decreasing healthcare costs. By prioritizing nutritional care, healthcare systems can combat the often-overlooked epidemic of malnutrition among their most vulnerable patients.

Key Factors Contributing to Malnutrition Risk

Advanced Age: Adults over 65 are particularly vulnerable due to physical decline, chronic diseases, and potential social isolation.
Chronic Illness: Conditions like cancer, chronic kidney disease, and inflammatory bowel disease disrupt nutrient intake, absorption, and metabolism.
Hospitalization: Acute stress from illness, trauma, or surgery significantly increases metabolic demands and can decrease appetite.
Dysphagia: Difficulty chewing or swallowing, common in elderly or neurological patients, severely limits nutritional intake.
Socioeconomic Factors: Low income, limited mobility, and lack of social support can restrict access to adequate and nutritious food.
Systemic Inflammation: Conditions like cancer cachexia involve an inflammatory response that drives muscle and fat wasting, compounding nutritional issues.
Mental Health Issues: Depression and dementia can lead to poor appetite and neglect of nutritional needs.

Frequently Asked Questions

Malnutrition is an imbalance of nutrients, which can include deficiencies, excesses, or imbalances in intake. It is not limited to being underweight; a patient can be overweight or obese and still be malnourished due to deficiencies in essential vitamins and minerals.

Severe malnutrition is often caused by conditions that involve chronic inflammation or significantly impact food intake and absorption. These include cancer (especially GI cancers), chronic obstructive pulmonary disease (COPD), liver disease, and inflammatory bowel diseases like Crohn's disease.

Hospitalization increases malnutrition risk through several factors, including the hypermetabolic stress response to illness or surgery, decreased appetite from illness or medication side effects, and practical challenges like restricted oral intake and frequent meal interruptions.

Key signs in elderly patients include unintentional weight loss, a low BMI, reduced appetite, fatigue, and weakness. Psychological factors like depression, social isolation, and functional limitations like poor dentition or dysphagia are also important indicators.

Early identification is best done through routine nutritional screening upon hospital admission, using validated tools like the Malnutrition Screening Tool (MST) or the Mini Nutritional Assessment (MNA). A comprehensive assessment by a dietitian is then performed for at-risk patients.

Treatment varies by severity and cause. It can range from nutritional counseling and oral supplements to medically supervised enteral feeding (tube feeding) or parenteral nutrition (IV feeding) for critically ill patients. Addressing underlying medical conditions is also crucial.

Yes, cancer treatments like chemotherapy and radiation can cause significant side effects that lead to malnutrition, such as nausea, vomiting, loss of appetite, and changes in taste perception. These effects, combined with the metabolic stress of the cancer itself, contribute to a high risk of cachexia.