Approach to weight loss in adults

Opening Vignette

Mr. Chan is a 67-year-old man with a past medical history of well-controlled hypertension and hyperlipidaemia. He visited your practice with concerns about weight loss from 65.8 kg to 59.2 kg over the past 6 months, after having lost his wife to cancer. He reported that he has no other symptoms.

WHAT IS SIGNIFICANT WEIGHT LOSS?

Weight loss of more than 5% of usual body weight over 6–12 months is considered significant.[1] It is important to clarify with patients whether the weight loss is unintentional or intentional. Intentional weight loss can be due to a controlled diet, increase in physical activity, and medications such as diuretic therapy in patients with heart failure or diabetes oral therapy (e.g. sodium-glucose cotransporter-2).

HOW COMMON IS THIS IN MY PRACTICE?

Unintentional weight loss occurs in 15%–20% of adults aged above 65 years.[1] It may present as a patient’s main complaint or may be observed as an incidental finding during weight screening when compared to previous weight records or reported by family members. It is pertinent to find the cause of unintentional weight loss, as it can lead to functional decline[2] and hip fractures,[3] and is associated with increased morbidity and mortality.[4]

WHAT CAN I DO IN MY PRACTICE?

Detailed history and clinical examination

A detailed history and clinical examination are necessary to guide the appropriate investigations to determine the cause of unintentional weight loss. The list of differentials can be broadly categorised into psychosocial and common organic causes.[5,6,7,8] Psychological causes include conditions such as dementia or depression, while social factors such as poverty or physical disability may compromise food security. Organic causes can be further divided into malignant and nonmalignant causes. Causes for nonmalignant weight loss include endocrinological disorders, rheumatological diseases and chronic heart disease or chronic kidney disease. These are further described in Figure 1. Box 1 shows a useful mnemonic for the causes of unintentional weight loss.[9]

Figure 1.

Chart shows the causes for unintentional weight loss.[5,6,7,8] HIV: human immunodeficiency virus

Box 1.

‘Meals on Wheels’ mnemonic for weight loss.[9]

Medication effects

Emotional problems

Anorexia nervosa, alcoholism

Late-life paranoia

Swallowing disorders

Oral factors (e.g. poorly fitting dentures, caries)

No money

Wandering and other dementia-related behaviour

Hyperthyroidism, hypothyroidism, hyperparathyroidism and hypoadrenalism

Enteric problems

Eating problems (e.g. inability to feed oneself)

Low-salt and low-cholesterol diet

Stones and social problems (e.g. isolation, inability to obtain preferred foods)

History-taking should start with the duration and amount of weight loss.[5,6,7,8] It may be useful to have a corroborative history from a family member or caregiver, especially if the patient is unable to independently provide a history. Previous health records, if available, can be used to determine if there has been objective weight loss.[7] A dietary history and systematic review should be done to identify any systemic disorders. This can help guide a targeted clinical examination and relevant investigations. A social history should be obtained to exclude any psychosocial cause of unintentional weight loss. A thorough family history may give a clue to certain diseases that a patient may be predisposed to. A comprehensive clinical examination, including examination of the cardiovascular, respiratory, gastrointestinal and neurological systems, should be done.[7] Often forgotten are the thyroid, breast, oral (e.g. dentition) and digital rectal examinations, as conditions related to these may not be symptomatic (other than weight loss) early on in the disease.

Diagnostic studies

While there is no universal tool to screen for causes of weight loss, there are specific questionnaires for individual conditions, such as the Patient Health Questionnaire-9[10] and the Abbreviated Mental Test,[11] which screen for depression and cognitive impairment, respectively. Diagnostic investigations include simple blood tests and radiological imaging such as a chest X-ray.[5,6,7,8,12,13] This is further described in Table 1. Cancer markers are not routinely performed due to low specificity leading to false positives.[14,15] Age-appropriate malignancy screening, such as mammogram and faecal immunological test, should be offered to all eligible patients [Table 2].[16]

Table 1.

Diagnostic studies for weight loss.[5,6,7,8,12,13]

Diagnostic test	Condition
Blood test
Full blood count	• Anaemia (blood loss, nutritional deficiency from low iron/B12 levels) • Haematological malignancies
Renal function	Chronic kidney disease
Liver function	• Hypoalbuminaemia may indicate poor nutrition and/or underlying organic pathology • Transaminitis, e.g., chronic liver disease
Thyroid function	Hyperthyroidism
FBG/HbA1c	Diabetes mellitus
Rheumatological markers	If rheumatological disease is suspected
Radiological imaging
Chest X-ray	• Lung masses • Cavitating lesions, e.g., tuberculosis • Congestive cardiac failure
Mammogram	Breast masses

FBG: fasting blood glucose

Table 2.

Adapted from MOH Screening Test Review Committee Guidelines 2019 — category 1 test.[14]

Screening test	Disease	Whom to screen
Colonoscopya	Colorectal cancer	Individuals aged ≥ 50 years
FITa	Colorectal cancer	Individuals aged ≥ 50 years
HPV DNA test	Cervical dysplasia/cervical intraepithelial lesion/cervical cancer	Women aged ≥ 30 years who ever had sexual intercourse
Pap smear	Cervical dysplasia/cervical intraepithelial lesion/cervical cancer	Women aged 25–29 years who ever had sexual intercourse
Mammogram	Breast cancer	Women aged 50–69 years Every 2 years

Category 1 screening tests are suitable for population-level screening; there is good and robust evidence that these tests are clinically effective and cost effective for use at the population level. ^aEither an annual faecal immunochemical test (FIT) or a 10-yearly colonoscopy is recommended for colorectal cancer screening in an average-risk individual aged ≥ 50 years. HPV: human papillomavirus, MOH: Ministry of Health

Management of abnormal weight loss

The management of abnormal weight loss requires a multidisciplinary approach, which may include a dietician, community nurses, psychologists and social workers. Community nurses may engage the patient’s caregiver or family member, especially when the patient is at home or in the community. Once a thorough history and clinical examination are performed, any reversible and treatable conditions confirmed through diagnostic studies should be managed accordingly. Dietitian and social worker reviews should be considered. If no cause is found or if the weight loss is less than 5% of the usual body weight, close follow-up, depending on clinical suspicion, is recommended. If there is further unintentional weight loss, the aforementioned proposed algorithm should be revisited to evaluate for occult pathology that may not have been present earlier.

WHEN SHOULD I REFER TO A SPECIALIST?

If initial investigations are unrevealing or if there are symptoms suggestive of an underlying pathology, a referral to the appropriate specialist may be warranted. This may include the need for computed tomography, endoscopic studies or nasoendoscopic evaluation.

TAKE-HOME MESSAGES

1. Weight loss of more than 5% of usual body weight over 6–12 months is considered significant.

2. Causes of weight loss can be classified as psychosocial, organic (malignant and nonmalignant) and unknown.

3. A comprehensive evaluation with a detailed history and clinical examination is necessary to guide the appropriate investigations needed to determine the cause of unintentional weight loss.

4. Other than treating the underlying cause , management of weight loss involves a multidisciplinary team approach. If no cause is found, close follow-up every 1–4 months depending on clinical suspicion is recommended.

5. A referral to a specialist is warranted if dedicated imaging or diagnostic procedures are required.

Closing Vignette

Initial examination and investigations were unremarkable. On further consultation, Mr. Chan reported low mood since the passing of his wife. He was diagnosed with reactive depression. After several months of counselling and a review by a dietician, Mr. Chan’s appetite starts to improve and he regains the weight he had lost.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

SMC CATEGORY 3B CME PROGRAMME

Online Quiz: https://www.sma.org.sg/cme-programme

Deadline for submission: 6 pm, 10 June 2024

Question: Answer True or False
1. Significant weight loss is defined as loss of more than 15% of body weight.
2. Patients presenting with unintentional weight loss would need to undergo a computed tomography scan and scopes to rule out malignancy.
3. Patients presenting with unintentional weight loss require sputum tests for tuberculosis as it is endemic in Singapore.
4. Hypothyroidism is not a cause for unintentional weight loss.
5. The human papillomavirus DNA test is done every 3 years.
6. The first step in the evaluation of unintentional weight loss is blood tests.
7. Patients with weight loss should have tumour markers done.
8. A colonoscopy needs to be repeated every 5 years after the age of 50 years for a low-risk individual.
9. Screening for colorectal cancer starts at 40 years of age.
10. Women aged ≥ 35 years presenting with unintentional weight loss should undergo a mammogram.
11. Women aged 25–29 years who ever had sexual intercourse should undergo a pap smear test.
12. Liver function tests should be done as part of the first-line tests in a patient presenting with unintentional weight loss.
13. Women aged 50–69 years should undergo annual mammogram screening.
14. Patients with significant weight loss should be referred to a specialist for further evaluation.
15. Patients presenting with unintentional weight loss should have an oral examination for dentition.
16. There is no role in screening for depression or cognitive impairment in a patient presenting with unintentional weight loss.
17. Rheumatological markers should be routinely checked in a person with significant unintentional weight loss.
18. The management of weight loss involves a multidisciplinary team that includes the dietician, social worker and community nurses.
19. If no cause of weight loss is found, the patient can be discharged from follow-up.
20. Patients with anaemia and unintentional weight loss always require scopes.