What is the appropriate work‑up for an adult older than 65 years who has unintentionally lost >5 % of body weight over the past 6–12 months?

Work-Up for Unintentional Weight Loss in Older Adults

Initial Clinical Evaluation

For an adult over 65 with >5% unintentional weight loss over 6-12 months, begin with a focused history targeting the most common causes: depression, malignancy (especially gastrointestinal and lung), cardiac disease, gastrointestinal disorders, and medication effects. 1, 2, 3

History Components

• Document precise weight trajectory: Confirm >5% loss in 6 months or >10% beyond 6 months, as this threshold indicates clinically significant malnutrition requiring urgent evaluation 4, 1
• Screen for depression using Geriatric Depression Scale (GDS-15): Score ≥5 requires follow-up, as depression accounts for a substantial proportion of cases, particularly in long-term care residents 1, 3
• Assess cognitive function with Mini-Cog or Blessed Orientation-Memory-Concentration test: Cognitive impairment strongly associates with weight loss and affects nutritional intake 1
• Evaluate functional status using Instrumental Activities of Daily Living (IADLs): Functional decline commonly accompanies weight loss and impacts ability to shop, cook, and feed oneself 1
• Review constitutional symptoms: Fever, night sweats, pain, and fatigue suggest malignancy, which accounts for 16-33% of cases 1, 2, 5
• Assess gastrointestinal symptoms: Dysphagia, nausea, vomiting, diarrhea, abdominal pain, and bowel habit changes—gastrointestinal disease causes weight loss in approximately 30% of patients 1, 6
• Conduct comprehensive medication review: Polypharmacy, hypoglycemic agents, antidepressants, and medications causing dysgeusia or nausea are frequently implicated 1, 2, 3
• Evaluate social factors: Isolation, financial constraints, and inability to access or prepare food contribute significantly 2, 7

Physical Examination

• Calculate BMI: BMI <21 kg/m² indicates significant nutritional risk requiring immediate intervention 1
• Examine for malnutrition signs: Temporal wasting, muscle wasting, prominent skeletal structures (ribs, spine, hip bones), and loss of subcutaneous fat 1, 8
• Assess volume status: Postural pulse changes ≥30 beats/min from lying to standing or severe postural dizziness indicate dehydration 1
• Measure handgrip strength: Reduced strength indicates functional muscle impairment and sarcopenia 8

Laboratory and Diagnostic Testing

Initial Laboratory Panel

• Complete blood count: Screen for anemia, infection, and hematologic malignancy 2, 3
• Basic metabolic panel: Evaluate electrolytes, renal function, and glucose 2
• Liver function tests: Assess for hepatobiliary disease 2
• Thyroid-stimulating hormone (ultrasensitive): Rule out hyperthyroidism 2, 3
• C-reactive protein and erythrocyte sedimentation rate: Identify inflammatory conditions 2
• Lactate dehydrogenase: Screen for malignancy and tissue breakdown 2
• Ferritin: Assess iron stores and inflammatory state 2
• Protein electrophoresis: Detect monoclonal gammopathies 2
• Urinalysis: Screen for renal disease and infection 2, 3
• Hemoglobin A1c: Evaluate for diabetes 1

Important caveat: Do not rely solely on serum albumin (<3.5 g/dL) as a nutritional marker—it primarily reflects inflammatory response rather than nutritional depletion, though low levels do correlate with increased morbidity and mortality 8

Age-Appropriate Cancer Screening

• Fecal occult blood testing: Mandatory given high prevalence of gastrointestinal malignancy 2, 3
• Chest radiography: Screen for lung cancer and other thoracic pathology 2

Tumor Markers (Selective Use)

While commonly ordered (CEA in 81%, PSA in 82%, CA 19-9 in 65% of cases), tumor markers should be used judiciously based on clinical suspicion rather than routine screening 5

Endoscopic Evaluation

• Upper gastrointestinal endoscopy: Has reasonably high yield in selected patients; used in approximately 71% of cases 3, 5
• Colonoscopy: Consider when gastrointestinal symptoms present or fecal occult blood positive; used in approximately 43% of cases 5

Rationale: Gastrointestinal disease accounts for 30% of all cases and 53% of malignant causes 6

Advanced Imaging

• Computed tomography: Consider based on initial findings; used in approximately 44% of cases 5

Nutritional Assessment

Use validated screening tools systematically: Malnutrition Universal Screening Tool (MUST), Nutritional Risk Screening 2002 (NRS-2002), or Short Nutritional Assessment Questionnaire (SNAQ) to evaluate nutritional risk 1

Diagnostic Yield and Follow-Up Strategy

Expected outcomes: A specific cause will be identified in 72-84% of patients 2, 6, 5

• Non-malignant diseases: 60% of diagnosed cases 6
• Malignancy: 16-24% of cases 6, 5
• Neuropsychiatric disorders: 11-24% of cases 6, 5
• Unknown cause: 16-28% of cases despite thorough evaluation 2, 3, 6

When Initial Evaluation is Unremarkable

Implement a 3-6 month observation period with regular weight monitoring and reassessment if new symptoms develop or weight loss continues 1, 2

The prognosis for unknown causes approximates that of non-malignant causes, which is significantly better than malignant causes 6

Critical Management Principles

Do not implement intentional weight loss strategies in patients with unintentional weight loss—the cardiovascular benefits of intentional ≥5% weight loss do not apply to unintentional weight loss, and dietary restriction without resistance exercise causes sarcopenia and bone loss, accelerating functional impairment and disability 1

Nutritional Intervention

• Provide 30 kcal/kg body weight per day with protein intake 1.2-1.5 g/kg/day for malnourished patients 1
• Add oral nutritional supplements providing ≥400 kcal/day with ≥30g protein when dietary measures are insufficient 1
• Ensure consistent meal timing with carbohydrates at each meal, particularly for diabetic patients 1
• Provide meals that are enjoyed by the patient and consider dietitian support for simplified meal planning 1

Exercise Considerations

If resistance training is implemented, schedule 2-5 times per week for 45-90 minutes per session to preserve muscle mass—but only if the patient's condition allows 1

Avoid Common Pitfalls

• Do not prescribe appetite stimulants or high-calorie supplements routinely—they lack FDA approval and clear evidence for weight loss treatment in elderly 3, 7
• Do not overlook medication review—polypharmacy and medication-induced dysgeusia or nausea are frequently reversible causes 2, 3
• Do not assume weight loss is normal aging—it almost always results from disease, disuse, or psychosocial factors 1