Quando rastrear alterações dos hormônios tiroidianos?

Screening in nonpregnant adults:

• thyroid screening guidelines
o American Association of Clinical Endocrinologists/American Thyroid Association (AACE/ATA) recommendations on screening in nonpregnant adults(7)
• consider screening for hypothyroidism in patients > 60 years old (AACE/ATA Grade B, Level 1)
 strong evidence that hypothyroidism is common in patients > 60 years old
 insufficient evidence of benefit or cost-effectiveness for screening
• consider aggressive case finding in patients at increased risk for hypothyroidism (AACE/ATA Grade B, Level 2)

o United States Preventive Services Task Force (USPSTF) finds insufficient evidence to recommend for or against routine screening for thyroid disease in adults (USPSTF Grade I recommendation)
• fair evidence that thyroid-stimulating hormone (TSH) screening can identify subclinical thyroid disease in asymptomatic patients
• poor evidence that treatment of subclinical thyroid disease improves clinically important outcomes
• Reference - Ann Intern Med 2004 Jan 20;140(2):125, supporting evidence review can be found in Ann Intern Med 2004 Jan 20;140(2):128, summary can be foundin Am Fam Physician 2004 May 15;69(10):2415 full-text

o American College of Physicians recommendations for asymptomatic patients
• mass screening of asymptomatic patients generally not recommended
• screen only in women > 50 years old with ≥ 1 symptom that could be caused by thyroid disease
• 71 patients need to be screened for 1 to be identified
• Reference - American College of Physicians guidelines on screening for thyroid disease (Ann Intern Med 1998 Jul 15;129(2):144 full-text), correction can be found inAnn Intern Med 1999 Feb 2;130(3):246, commentary can be found in Ann Intern Med 1998 Jul 15;129(2):135, Ann Intern Med 1999 Jan 19;130(2):161

• offer annual screening to patients with conditions or exposures associated with high risk of developing hypothyroidism, including(1)
o Down syndrome
o Turner syndrome
o certain medications, for example amiodarone, lithium, thalidomide, interferons, sunitinib, and rifampicin
o radiation therapy to neck
o radioiodine treatment
o subtotal thyroidectomy
o diabetes mellitus type 1
o autoimmune Addison disease

• insufficient evidence to determine benefits and harms of screening for thyroid dysfunction in nonpregnant asymptomatic adults
o based on systematic review for United States Preventive Services Task Force
o systematic review of 14 studies (13 randomized trials, 1 cohort study) evaluating screening and treatment of subclinical and screening-detected overt hypothyroidism and hyperthyroidism in adults without goiter or thyroid nodules
o each identified randomized trial included 14-120 adults, all studies excluded pregnant women
o no study directly compared
• clinical benefits and harms of screening for thyroid dysfunction to no screening
• treatment of screen-detected overt thyroid dysfunction to no treatment or waiting for symptomatic presentation to initiate treatment
o for treatment of subclinical hypothyroidism, comparing treatment to control (no treatment or placebo)
• treatment associated with decreased risk for coronary heart disease events in 1 fair-quality cohort study with 4,735 adults
• no clear benefit associated with treatment for quality of life, cognitive function, blood pressure, or body mass index in identified randomized trials
o for treatment of subclinical hyperthyroidism, no study evaluated clinical outcomes with treatment vs. no treatment
o Reference - Ann Intern Med 2014 Oct 28 early online full-text

• no randomized or controlled trials found evaluating screening for subclinical thyroid dysfunction
o based on systematic review
o Reference - AHRQ Comparative Effectiveness Review 2011 Nov:24 PDF

• routine screening appears unwarranted in hospitalized patients
o in unselected general medical, geriatric, or psychiatric inpatient populations, TSH testing has many false-positive results and low yield of true-positive
o based on systematic literature review
o 1%-2% prevalence of thyroid disease among inpatients similar to outpatient population
o positive likelihood ratio associated with abnormal TSH test result (cutpoint of TSH > 20 microunits/mL) in ill inpatients is about 10 compared with about 100 in outpatients
o Reference - Arch Intern Med 1999 Apr 12;159(7):658, commentary can be found in Evidence-Based Medicine 2000 Jan-Feb;5(1):29

• normal TSH likely to remain normal for at least 5 years, while abnormal TSH often normal with repeat testing
o based on health management organization data for 422,242 outpatients without thyroid disease or pregnancy who had TSH levels measured and had 5-year follow-up
o 95% initial serum TSH levels were normal (0.35-5.5 milliunits/L) of which 98% remained normal
o 1.2% initial TSH levels were decreased (< 0.35 milliunits/L) of which 62% of patients not taking thyroid-specific medications had subsequent normal TSH levels
o 3% initial TSH levels were increased (5.5-10 milliunits/L) of which 51% of patients not taking thyroid-specific medications had subsequent normal TSH levels
o 0.7% initial TSH levels were highly increased (> 10 milliunits/L) of which 27% of patients not taking thyroid-specific medications had subsequent normal TSH levels
o Reference - Arch Intern Med 1999 Apr 12;159(7):658, commentary can be found in Evidence-Based Medicine 2000 Jan-Feb;5(1):29