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Unintentional weight loss is a common problem, especially in older adults, and is associated with increased mortality.
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The most common causes are malignancy, nonmalignant gastrointestinal diseases, and psychiatric disorders in community-dwelling adults; psychiatric disorders are the most common cause identified in institutionalized older adults.
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Treatment of unintentional weight loss is aimed at managing the underlying causes.
Approach to Patients with Unintentional Weight Loss
Section snippets
Key points
Nature of the problem
Several large studies have shown an association between unintentional weight loss and mortality in specific populations, including American women aged 55 to 69,4 British men aged 56 to 75,5 and overweight and obese American people aged 35 and over.6
The connection between unintentional weight loss and mortality is especially important given that unintentional weight loss is not uncommon. One large survey study among people 45 years of age and older found that 5% of participants reported
Definitions
Beginning in the third decade of life, physiologic changes to body mass composition as a result of the normal process of aging leads to lean body mass decline at a rate of 0.3 kg/y with a simultaneous increase in body fat. The net result of these changes is an increase in total body weight that peaks in the fifth to sixth decade of life, with weight remaining stable until age 65 to 70.9 By the seventh decade, patients begin to lose weight at a rate of 0.1 to 0.2 kg/y; unintentional weight loss
Pathophysiology
Cancer cachexia may provide insight into the biological mechanisms behind unintentional weight loss. The proinflammatory cytokines, tumor necrosis factor alpha, interleukin-1, and interleukin-6, are implicated in driving cancer cachexia by promoting anorexia as well as muscle and fat catabolism.12
In order to maintain body weight homeostasis, energy intake must be equivalent to energy expenditure. In cancer cachexia, however, the decreased caloric intake does not result in decreased energy
Causes of unintentional weight loss
Unintentional weight loss is a marker for serious underlying pathologic condition. Several studies that investigated causes of unintentional weight loss found that malignancy is the most common cause, found in 15% to 37% of patients.16, 17, 18 Nonmalignant gastrointestinal causes (particularly malabsorption disorders) constitute 10% to 20% of cases,17, 18, 19, 20 whereas psychiatric disorders (particularly depression) make up another 10% to 23% of cases of unintentional weight loss.16, 17, 18
Causes of weight loss in older adults
Unintentional weight loss is common in older adults and occurs in about 15% to 20% of geriatric patients.44 It is even more prevalent in high-risk populations, such as nursing home residents, with estimates of up to 60%.45 Unintentional weight loss in older adults is associated with an increased risk of mortality even when controlling for potential confounders like smoking and alcohol use,46 sedentariness,44 and comorbidities.44,46,47 It is also associated with a decline in activities of daily
Approach
The workup of unintentional weight loss relies on a thorough history and physical examination to diagnose disease and guide testing (Fig. 1). A clinical history should include the amount and pace of weight loss; dietary assessment; psychosocial factors; and associated symptoms, such as joint pain, dyspnea, diarrhea, gastrointestinal bleeding, dental problems, and depressed mood. Clinicians should review all medications, supplements, and chronic medical conditions. A physical examination can
Therapeutic options
Treatment of patients with unintentional weight loss involves treating the underlying cause. A thorough history and physical examination are vital in order to identify the cause of weight loss and can be supplemented by laboratory tests as well as age-appropriate cancer screening. An interprofessional approach, including dietitians, speech therapists (for evaluation of oropharyngeal dysphagia), and social services, is imperative in treating unintentional weight loss.40
Several medications, most
Summary
Clinically significant weight loss is defined as a loss of at least 5% of body weight over 6 to 12 months. There is an increase in morbidity and mortality associated with unintentional weight loss. The differential diagnosis of involuntary weight loss is broad and requires consideration of physiologic, pathologic, and psychosocial factors. Treatment largely depends on targeting the underlying cause; therefore, clinicians must perform a thorough history and physical examination and consider
Clinics care points
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Many studies define clinically significant weight loss as at least 5% of usual body weight over 6 to 12 months (source 11).
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Weight loss is associated with many chronic diseases.
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A careful medication history is essential in the workup of weight loss; medications may lead to weight loss through several mechanisms.
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Nutritional supplements should be used to supplement rather than replace regular meals (source 59).
Disclosure
Dr. Shaw supported in part by a Joachim Silbermann Family Clinical Scholar Award in Geriatrics from the Rosanne H. Silbermann Foundation.
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