Subclinical hypothyroidism: Difference between revisions

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==Treatment==
==Treatment==
"In current RCTs, levothyroxine  replacement therapy for subclinical hypothyroidism did not result in  improved survival or decreased cardiovascular morbidity" according to a [[meta-analysis]] by the [[Cochrane Collaboration]]. <ref  name="pmid17636722">{{cite journal| author=Villar HC, Saconato H,  Valente O, Atallah AN| title=Thyroid hormone replacement for subclinical  hypothyroidism. | journal=Cochrane Database Syst Rev | year= 2007 |  volume=  | issue= 3 | pages= CD003419 | pmid=17636722 |  doi=10.1002/14651858.CD003419.pub2 | pmc= | url= }}  [http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=18170994  Review in: ACP J Club. 2008 Jan-Feb;148(1):7]  [http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=18170993  Review in: ACP J Club. 2008 Jan-Feb;148(1):6]  [http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=18234930  Review in: Evid Based Med. 2008 Feb;13(1):22] </ref>
"In current RCTs, levothyroxine  replacement therapy for subclinical hypothyroidism did not result in  improved survival or decreased cardiovascular morbidity" according to a [[meta-analysis]] by the [[Cochrane Collaboration]]. <ref  name="pmid17636722">{{cite journal| author=Villar HC, Saconato H,  Valente O, Atallah AN| title=Thyroid hormone replacement for subclinical  hypothyroidism. | journal=Cochrane Database Syst Rev | year= 2007 |  volume=  | issue= 3 | pages= CD003419 | pmid=17636722 |  doi=10.1002/14651858.CD003419.pub2 | pmc= | url= }}  [http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=18170994  Review in: ACP J Club. 2008 Jan-Feb;148(1):7]  [http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=18170993  Review in: ACP J Club. 2008 Jan-Feb;148(1):6]  [http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=18234930  Review in: Evid Based Med. 2008 Feb;13(1):22] </ref> Subsequent [[randomized controlled trial]]s have been positive<ref name="pmid17299073">{{cite journal| author=Razvi S, Ingoe L, Keeka G, Oates C, McMillan C, Weaver JU| title=The beneficial effect of L-thyroxine on cardiovascular risk factors, endothelial function, and quality of life in subclinical hypothyroidism: randomized, crossover trial. | journal=J Clin Endocrinol Metab | year= 2007 | volume= 92 | issue= 5 | pages= 1715-23 | pmid=17299073 | doi=10.1210/jc.2006-1869 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=17299073  }} </ref> and negative<ref name="pmid20501682">{{cite journal| author=Parle J, Roberts L, Wilson S, Pattison H, Roalfe A, Haque MS et al.| title=A randomized controlled trial of the effect of thyroxine replacement on cognitive function in community-living elderly subjects with subclinical hypothyroidism: the Birmingham Elderly Thyroid study. | journal=J Clin Endocrinol Metab | year= 2010 | volume= 95 | issue= 8 | pages= 3623-32 | pmid=20501682 | doi=10.1210/jc.2009-2571 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20501682  }} </ref>.


==Screening==
==Screening==

Revision as of 09:18, 19 April 2012

In medicine, subclinical hypothyroidism is an elevated thyrotropin (TSH) concentration can maintain a normal or near normal thyroxine (T4) concentration.[1][2]

Prognosis

Thyrotropin level

Evolution of thyrotropin values over 5 years.[3]
  Follow-up TSH value
TSH > 10 TSH < 10
TSH > 10 35% 64%
TSH 5.5 - 10 3% 97%

The thyrotropin level helps predict progression to overt hypothyroidism.[3]

Antithyroid peroxidase antibodies

Antithyroid peroxidase (also called antithyroid microsomal) antibodies my help predict progression to overt hypothyroidism.[4][5][6]

Diagnostic accuracy for predicting over hypothyroidism has been reported.

Diez et al found that among patients with TSH > 5, antibodies > 20 U/ml were significant predictors of hypothyrodism after 3.5 years of follow-up in which 26% developed overt hypothyroidism, but not after controlling for initial thyrotropin level.[6]

  • Sensitivity 93%
  • Specificity 30%
  • Positive predictive value 32%
  • Negative predictive value 92%

Walsh et al found that among patients with TSH> 4, antibodies > 35 U/ml were significant predictors of hypothyrodism after 13 years of follow-up in which 31% developed overt hypothyroidism, but not after controlling for initial thyrotropin level.[4]

  • Sensitivity 84%
  • Specificity 30%
  • Positive predictive value 60%
  • Negative predictive value 60%

Treatment

"In current RCTs, levothyroxine replacement therapy for subclinical hypothyroidism did not result in improved survival or decreased cardiovascular morbidity" according to a meta-analysis by the Cochrane Collaboration. [7] Subsequent randomized controlled trials have been positive[8] and negative[9].

Screening

The US Preventive Services Task Force states:[10]

"t is uncertain whether treatment will improve quality of life in otherwise healthy patients who have abnormal TSH levels and normal free thyroxine levels."

References

  1. Surks MI, Ortiz E, Daniels GH, Sawin CT, Col NF, Cobin RH et al. (2004). "Subclinical thyroid disease: scientific review and guidelines for diagnosis and management.". JAMA 291 (2): 228-38. DOI:10.1001/jama.291.2.228. PMID 14722150. Research Blogging.
  2. Cooper DS, Biondi B (2012). "Subclinical thyroid disease.". Lancet 379 (9821): 1142-54. DOI:10.1016/S0140-6736(11)60276-6. PMID 22273398. Research Blogging.
  3. 3.0 3.1 Meyerovitch J, Rotman-Pikielny P, Sherf M, Battat E, Levy Y, Surks MI (2007). "Serum thyrotropin measurements in the community: five-year follow-up in a large network of primary care physicians.". Arch Intern Med 167 (14): 1533-8. DOI:10.1001/archinte.167.14.1533. PMID 17646608. Research Blogging. Cite error: Invalid <ref> tag; name "pmid17646608" defined multiple times with different content
  4. 4.0 4.1 Walsh JP, Bremner AP, Feddema P, Leedman PJ, Brown SJ, O'Leary P (2010). "Thyrotropin and thyroid antibodies as predictors of hypothyroidism: a 13-year, longitudinal study of a community-based cohort using current immunoassay techniques.". J Clin Endocrinol Metab 95 (3): 1095-104. DOI:10.1210/jc.2009-1977. PMID 20097710. Research Blogging. Cite error: Invalid <ref> tag; name "pmid20097710" defined multiple times with different content
  5. Li Y, Teng D, Shan Z, Teng X, Guan H, Yu X et al. (2008). "Antithyroperoxidase and antithyroglobulin antibodies in a five-year follow-up survey of populations with different iodine intakes.". J Clin Endocrinol Metab 93 (5): 1751-7. DOI:10.1210/jc.2007-2368. PMID 18270254. Research Blogging.
  6. 6.0 6.1 Díez JJ, Iglesias P (2004). "Spontaneous subclinical hypothyroidism in patients older than 55 years: an analysis of natural course and risk factors for the development of overt thyroid failure.". J Clin Endocrinol Metab 89 (10): 4890-7. DOI:10.1210/jc.2003-032061. PMID 15472181. Research Blogging. Cite error: Invalid <ref> tag; name "pmid15472181" defined multiple times with different content
  7. Villar HC, Saconato H, Valente O, Atallah AN (2007). "Thyroid hormone replacement for subclinical hypothyroidism.". Cochrane Database Syst Rev (3): CD003419. DOI:10.1002/14651858.CD003419.pub2. PMID 17636722. Research Blogging. Review in: ACP J Club. 2008 Jan-Feb;148(1):7 Review in: ACP J Club. 2008 Jan-Feb;148(1):6 Review in: Evid Based Med. 2008 Feb;13(1):22
  8. Razvi S, Ingoe L, Keeka G, Oates C, McMillan C, Weaver JU (2007). "The beneficial effect of L-thyroxine on cardiovascular risk factors, endothelial function, and quality of life in subclinical hypothyroidism: randomized, crossover trial.". J Clin Endocrinol Metab 92 (5): 1715-23. DOI:10.1210/jc.2006-1869. PMID 17299073. Research Blogging.
  9. Parle J, Roberts L, Wilson S, Pattison H, Roalfe A, Haque MS et al. (2010). "A randomized controlled trial of the effect of thyroxine replacement on cognitive function in community-living elderly subjects with subclinical hypothyroidism: the Birmingham Elderly Thyroid study.". J Clin Endocrinol Metab 95 (8): 3623-32. DOI:10.1210/jc.2009-2571. PMID 20501682. Research Blogging.
  10. Helfand M, U.S. Preventive Services Task Force (2004). "Screening for subclinical thyroid dysfunction in nonpregnant adults: a summary of the evidence for the U.S. Preventive Services Task Force.". Ann Intern Med 140 (2): 128-41. PMID 14734337[e]