Hypothyroidism: an update

Area of Science:

• Endocrinology
• Internal Medicine
• Primary Care

Background:

• Hypothyroidism is a prevalent endocrine disorder affecting approximately 1 in 300 individuals in the United States.
• Untreated hypothyroidism is associated with significant comorbidities including hypertension, dyslipidemia, infertility, cognitive impairment, and neuromuscular dysfunction.
• Prevalence increases with age and is notably higher in females.

Purpose of the Study:

• To provide a comprehensive overview of hypothyroidism for primary care physicians.
• To discuss the etiology, diagnosis, and management of hypothyroidism.
• To identify patient subgroups who may benefit from therapy for subclinical hypothyroidism.

Main Methods:

• Review of data from the National Health and Nutrition Examination Survey for prevalence estimation.
• Discussion of clinical presentation, diagnostic laboratory assessments (serum thyroid-stimulating hormone), and common etiologies (autoimmune thyroid disease).
• Evaluation of treatment strategies, including levothyroxine monotherapy and combination therapy, and criteria for treating subclinical hypothyroidism.

Main Results:

• Serum thyroid-stimulating hormone (TSH) is the primary laboratory test for assessing thyroid function.
• Levothyroxine monotherapy is the recommended treatment for hypothyroidism, with most patients requiring lifelong administration.
• Subclinical hypothyroidism patients with TSH > 10 mIU/L or positive thyroid peroxidase antibodies may be candidates for therapy.

Conclusions:

• Hypothyroidism is a common condition manageable with synthetic levothyroxine, often necessitating lifelong treatment.
• Screening asymptomatic adults for hypothyroidism is not supported by current evidence regarding improved outcomes.
• Careful consideration for therapy in subclinical hypothyroidism is warranted for high-risk individuals.