Thyroid Work-Up for Patients With Obesity
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A new guideline from the European Society of Endocrinology recommends routine testing of thyroid function for patients with obesity. Testing for other endocrine-related conditions should be guided by the presence of symptoms.
The thyroid function and obesity are closely tied with each other. Some endocrine disorders, like hypothyroidism and Cushing’s syndrome, cause significant weight gain and push patients to develop complications related to obesity. Obesity, in turn, can push patients towards endocrine dysfunction.
This complex relationship often makes it hard for healthcare providers to determine which condition is the cause and the effect. Deciding on the most effective testing strategies to cover both endocrine problems and obesity also proves to be quite challenging. To help healthcare providers deal with these challenges, the European Society of Endocrinology recently weighed in with help.
“Endocrine Work-up in Obesity” is a new clinical practice guideline with evidence-based advice on testing in a variety of conditions. It was first published in the January issue of the
The guideline notes that increased BMI leads to a number of hormonal changes. “Concomitant hormonal diseases can be present in obesity and have to be properly diagnosed — which in turn might be more difficult due to alterations caused by body fatness itself.”
However, regardless of any testing strategies, the guideline underscores that weight loss is more effective in treating obesity-related conditions than attempting to treat endocrine conditions independently. The guideline says, “weight loss in obesity should be emphasized as key to the restoration of hormonal balances.”
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Thyroid Function in Obesity
Since hypothyroidism is highly prevalent in patients with obesity, the guideline recommends that all patients with obesity should be tested for thyroid function. This is the only condition for which it recommends testing without the need for signs and symptoms.
Thyroid screening in patients with obesity is recommended by the guideline not only because of its prevalence. It is also recommended because of hypothyroidism’s role in potentiating weight gain and worsening comorbidities in obesity. The screening is also “simple, and treatment is inexpensive and safe.”
Symptoms of hypothyroidism, such as fatigue, depression, cramps, menstrual disturbance, and weight gain, are nonspecific and can be confused with those of obesity. If hypothyroidism truly is present, it increases the risk of obesity to develop cardiovascular risk factors and metabolic syndrome. Hypothyroidism also contributes to an unfavorable lipid profile, which then increases vascular risk. Apart from that, hypothyroidism can also affect harmful attempts at losing weight.
Thyroid-stimulating hormone levels should be tested on patients with obesity. If TSH levels are elevated, free T4 and antibodies should also be measured.
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Hypercortisolism
In his commentary on the guideline, John P.H. Wilding, M.D., a professor at the University of Liverpool, shared that “with the exception for hypothyroidism, most thyroid testing is not recommended in the absence of clinical features of endocrine syndromes in obesity, and likewise hormone treatment is rarely needed.”
Testing for hypercortisolism should not be performed routinely, but it is recommended for patients suspected of the condition. The guideline also specifies that patients who use corticosteroids are not typically recommended for hypercortisolism. However, testing should be considered for patients using corticosteroids and also planning on undergoing bariatric surgery.
If testing for hypercortisolism is in order, an overnight dexamethasone suppression test is recommended as the first screening tool.
Male Hypogonadism
Although thyroid testing for hypogonadism is not routinely recommended in male patients with obesity, the guideline recommends investigating key clinical signs and symptoms, such as erectile dysfunction, reduced sexual desire, muscle weakness, changes in mood, fatigue, cognitive impairment, and more.
Testing for hypogonadism is not routinely recommended for male patients with obesity. However, the guideline recommends investigating key clinical signs and symptoms. Patients with hypogonadism often present with erectile dysfunction, reduced sexual desire, muscle weakness, changes in mood, and fatigue.
If clinical features of hypogonadism are present, the guideline suggests measuring total and free testosterone, sex hormone-binding globulin (SHBG), follicle-stimulating hormone (FSH), and luteinizing hormone (LH).
Gonadal Dysfunction in Women
The guideline recommends against routine testing for gonadal dysfunction among female patients with obesity. Testing is only recommended for those who exhibit symptoms of gonadal dysfunction, such as menstrual irregularities, chronic anovulation, and infertility.
Furthermore, the approach to testing depends on the suspected condition. Female patients with obesity who present with menstrual irregularity are recommended testing for LH, FSH, total testosterone, SHBG, androstenedione, estradiol, 17-hydroxyprogesterone, and prolactin. For those with irregular menstruation whose cycles are somewhat predictable, the assessment should take place during the early follicular phase. For evaluation of anovulation, the guideline suggests measuring LH, FSH, estradiol, progesterone, and prolactin.
When clinical features suggest polycystic ovarian syndrome, the guideline recommends assessing androgen excess. More specifically, the guideline suggests the measurement of the total testosterone, free testosterone, androstenedione, and SHBG. Ovarian morphology and blood glucose assessment are also recommended.
Other Hormones
Apart from the main endocrine conditions associated with obesity, the guideline also recommended against routine testing for the following:
Growth factor, or insulin-like growth factor 1, except for patients with suspected hypopituitarism
Vitamin D deficiency
Hyperparathyroidism
Leptin and Ghrelin, unless the patient is suspected with syndromic obesity
The guideline also suggested that secondary causes of hypertension should be considered in the context of therapy-resistant hypertension in obesity.
Thyroid Testing Guideline in US Patients with Obesity
Wilding notes in his commentary that “these guidelines should help reduce unnecessary endocrine testing in those referred for assessment of obesity and encourage clinicians to support patients with their attempts at weight loss, which if successful has a good chance of correcting any endocrine dysfunction.”
According to Dr. Robert F. Kushner, professor of medicine and medical education and director of the Center for Lifestyle Medicine at Northwestern University, these new guidelines “will be a welcome addition to the other existing obesity guidelines.”
“The guidelines are structured as a logical set of practical and clinically useful recommendations that apply to patients who present with obesity. They not only identify when an endocrinological workup and referral is recommended, but also provide specific guidance on commonly encountered medical co-morbid conditions that are seen in the obesity population, such as hypothyroidism, erectile dysfunction, and menstrual irregularity. They do not appear to conflict with recommendations and standards used in the U.S.,” Kushner says.