The mainstay of evaluation for unintentional weight loss involves a detailed history, thorough clinical examination, and baseline laboratory investigations. It is important to first establish the extent of weight loss. While serial measurements of body weight offer the simplest screening tool, it may not always be possible, especially for frail patients who are no longer able to stand. If it is not possible to measure weight directly, a change in clothing size or corroboration of weight loss by a caregiver can be helpful. Questions about appetite may help elucidate whether the weight loss is caused by inadequate energy intake or has occurred despite an adequate intake. Several screening tools exist for identifying older adults at risk for poor nutrition.

Previous and current medical history can identify conditions that can lead to weight loss and drugs that may contribute via their side effects. Obtaining an accurate chief complaint is important, as it has been found to lead to etiology of weight loss in a considerable proportion of cases. A history that includes a review of systems may elicit additional symptoms (e.g., cough, nausea/vomiting, abdominal pain) that might direct further investigation. All elderly patients with weight loss should undergo screening for dementia and depression using standardized assessment tools [67]. A detailed social history can elicit information on alcohol intake and smoking and shed light on the patient’s living situations. With whom does she live? Who buys and prepares the food? Is there any help from aides or family members? Home-based medical providers have a unique opportunity to obtain this information firsthand by speaking with the caregivers during home visits and doing “refrigerator biopsy” and direct surveillance of the home.

In patients with unintentional weight loss, a full physical examination should aim to exclude major cardiovascular and respiratory illnesses, as well as abdominal masses, organomegaly, prostate enlargement, and breast masses that may indicate cancer. The physical examination can aid in evaluating concerns prompted by history findings. Evaluation of the oral cavity may indicate difficulty with chewing or swallowing. Baseline investigations should be guided by patients’/proxies’ goals of care and findings from history and physical exam and aim to identify reversible and easily treated causes.

Recommended laboratory tests include complete blood count, basic metabolic panel, liver function tests, thyroid function tests, C-reactive protein levels, erythrocyte sedimentation rate, lactate dehydrogenase measurement, and urinalysis [48]. Chest radiography, fecal occult blood testing, and abdominal ultrasonography can also be considered in the home setting if history and exam suggest pulmonary or gastrointestinal involvement, respectively. In one prospective study of 101 patients with an average age of 64 years, the etiology of unintentional weight loss was established in 72 % patients with the basic evaluation described above [65]. Organic disease was identified in 57 patients, and 16 patients had a psychiatric diagnosis. More importantly, all of the 22 patients with malignant disease had abnormal results in the baseline assessment. Tests with the highest yield were C-reactive protein, hemoglobin, lactate dehydrogenase, and albumin measurements. None of the 25 patients with negative findings on baseline evaluation had a malignancy on additional workup, such as computed tomography, endoscopy, colonoscopy, magnetic resonance imaging, or radionuclide examinations.

Therefore, if baseline test results are normal, close observation for 3–6 months is justified [57, 67]. Continued watchful waiting is a reasonable strategy. Undirected pan-body scanning is not recommended. There are no clear guidelines for how to proceed in the assessment of a patient with weight loss and negative initial findings. The diagnostic yield of a thoracic/abdominal/pelvic CT examination to assess for occult or metastatic disease has not been determined. Incidental findings are common, the studies are costly, and they may be inappropriate or impossible to obtain in patients who are frail or who have multiple comorbidities. Clear and prompt communications with the patient and family regarding the initial evaluation are critical, and conversations regarding risks/burdens vs. benefits of further testing and goals of care should be ongoing.

Common strategies to address unintentional weight loss in older homebound adults are dietary changes, environmental modifications, nutritional supplements, and flavor enhancers [68]. Examples include:

Physical therapy may help patients increase their amount of exercise, to thereby stimulate appetite and increase energy intake and muscle mass [72].

When weight loss becomes resistant to nutritional intervention at the end of life or when cachexia worsens as the underlying disease progresses, it is important to focus on the comfort measures that are consistent with the patient’s goals of care. These measures can include careful hand feeding for pleasure eating while minimizing aspiration risk, treating pain and nausea aggressively, and proper oral care. Home hospice referral not only can provide the patients the necessary support but is also invaluable in educating and supporting the families and caregivers. Watching loved ones lose weight and stop eating is inevitably difficult for family members. If patients start having difficulty swallowing or no longer care to eat, feeding tubes are often considered as a way to prolong life. Since the benefit of feeding tube varies in different medical conditions and the discussion of artificial nutrition and hydration is complex and often emotionally charged, we will not discuss it in depth in this chapter. But the evidence shows that feeding tubes do not provide adequate nutrition, prolong life, prevent aspiration, or improve comfort in patients with advanced dementia [73, 74]. In these difficult situations, home-based medical providers can provide important guidance to allow patients and families to make decisions that reflect their preferences and goals.

Several medications to stimulate appetite are available, but limited evidence exists to support the use of any pharmacologic agent for the treatment of weight loss. The existing literature is mostly small, uncontrolled studies, and benefits are generally restricted to a small gain in weight without evidence of decreased morbidity and mortality or improved function and quality of life [75]. Most of these agents have significant side effects, particularly in frail elderly people, which limit their usefulness. Thus, home-based medical providers should weigh the risks and benefits carefully with the patient and family. It is our general practice not to use appetite stimulants.

Megestrol, a progestational agent, has been shown to improve appetite and increase weight gain in patients with cancer and AIDS cachexia. Its use in AIDS patients is also associated with higher mortality rates [63]. However, studies in older patients are limited, and there are insufficient data to define an optimal dose. Adverse effects of megestrol include gastrointestinal upset, insomnia, impotence, hypertension, thromboembolic events, and adrenal insufficiency.

Mirtazapine, a serotonin antagonist used to treat depression, is another possible treatment for unintentional weight loss in older patients because 12 % of patients who take this drug for depression report weight gain [76]. Although no literature exists to support its use for unintentional weight loss, mirtazapine may be a good choice for treatment of depression in older patients who also have unintentional weight loss. Because dizziness and orthostatic hypotension are possible adverse effects of mirtazapine, caution is warranted in patients at risk of falls [46]. Dronabinol has been shown to improve appetite in patients with AIDS [77], but is associated with significant adverse effects, particularly central nervous system toxicity (sedation, fatigue, hallucination).