Thyroid function testing in primary care: overused and under-evidenced? A study examining which clinical features...

Area of Science:

• Endocrinology
• Primary Care Medicine
• Diagnostic Testing

Background:

• Diagnostic testing for thyroid disease is increasing in primary care settings.
• Identifying clinical features associated with abnormal thyroid stimulating hormone (TSH) results is crucial for efficient diagnosis.

Purpose of the Study:

• To examine clinical features associated with abnormal thyroid stimulating hormone (TSH) results in a primary care population.
• To determine the diagnostic yield of thyroid disease testing in general practice.

Main Methods:

• A cross-sectional study of 16,487 patients in a UK general practice.
• Analysis of primary care records for TSH tests conducted over one year, extracting symptoms and indications for testing.
• Multivariable logistic regression used to identify associations between clinical features and abnormal TSH results, followed by a cohort study.

Main Results:

• 12% of the patient population underwent TSH testing, with a diagnostic yield of 2.1% for thyroid disease.
• Clinical features associated with abnormal TSH included pregnancy, constipation, palpitations, hair loss, weight gain, and diarrhea.
• Pregnancy and constipation were linked to elevated TSH (hypothyroidism), while palpitations, hair loss, weight gain, and diarrhea were linked to low TSH (hyperthyroidism).

Conclusions:

• The diagnostic yield of thyroid disease testing in this primary care setting was 2.1%.
• Targeting TSH testing based on specific clinical features may improve diagnostic efficiency without missing cases.
• Observed symptoms associated with thyroid disease differed from commonly reported ones, potentially indicating fewer patients presenting with advanced disease.