Lessons Learned from Community Based Thyroid Screening
Sunday, November 04, 2007
A retrospective analysis of the computerized database of a large health medical organization in Tel Aviv, Israel that included 2800 primary care physicians and 2.3 million insured persons, recently revealed some very interesting findings about routine thyroid screening (Arch Intern Med 2007;167(14):1533-38). A total of 422,242 persons aged 21 years and older with no known thyroid disease or previous treatment with thyroid medications, who had at least one TSH measurement during 2002 and were available for follow-up through 2006, were included in the study. The TSH reference range used for this study was 0.35-5.5 mIU/L.
Ninety five percent of the initial TSH concentrations were within normal limits, whereas 3.7% were elevated and 1.2% were decreased. Thirty seven percent of patients with abnormal initial TSH levels were treated with medication and excluded from further analysis. The remaining patients had an average of 3.7 additional TSH measurements during the 5 year follow-up.
- Of the patients with initially normal TSH results, 98% remained normal at the end of 5 years.
- Of the patients with initially elevated TSH results, 38% remained elevated and 62% returned to normal.
- Of the patients with initially decreased TSH results, 47% remained decreased and 52% reverted to normal.
Two important conclusions can be drawn from this study. When TSH concentration is normal and there are no new clinical indications of a thyroid disorder, the likelihood of a subsequent abnormal TSH level within 5 years is only 2%. This finding supports recent evidence based recommendations against population based TSH screening. Secondly, more than 50% of patients with abnormal TSH results revert to normal without medical intervention, suggesting that at least two TSH measurements should be obtained before considering treatment.
posted by Fred Plapp @ 8:52 PM,
