A 2013 survey of clinical practice patterns in the management of primary hypothyroidism

Context: In 2012, comprehensive clinical practice guidelines (CPGs) were published regarding the management of hypothyroidism. Objective: We sought to document current practices in the management of primary hypothyroidism and compare these results with recommendations made in the 2012 American Thyroid Association (ATA)/American Association of Clinical Endocrinologists (AACE) hypothyroidism CPGs. In addition, we sought to examine differences in management among international members of U.S.-based endocrine societies and to compare survey results with those obtained from a survey of ATA members performed 12 years earlier. Methods: Clinical members of The Endocrine Society (TES), the ATA, and the AACE were asked to take a web-based survey consisting of 30 questions dealing with testing, treatment, and modulating factors in the management of primary hypothyroidism. Results: In total, 880 respondents completed the survey, including 618 members of TES, 582AACEmembers, and 208 ATA members. North American respondents accounted for 67.6%, Latin American 9.7%, European 9.2%,AsiaandOceania8.1%,andAfricaandMiddleEast5.5%. Overthypothyroidismwouldbetreatedusing L-T4 aloneby99.2%of respondents;0. 8%wouldusecombinationL-T4andliothyronine (L-T3) therapy. Generic L-T4wouldbeused by49.3%anda brandnameby 49.9%.Therate of replacementwouldbegradual (38.5%); an empiric dose, adjusted to achieve target (33.6%); or a calculated full replacement dose (27.8%). A target TSH of 1.0 to 1.9 mU/L was favored in the index case, but 3.0 to 3.9 mU/L was the most commonly selected TSH target for an octogenarian. Persistent hypothyroid symptoms despite achieving a target TSH would prompt testing for other causes by 84.3% of respondents, a referral to primary care by 11.3%, and a change to L-T4 plus L-T3 therapy by 3.6%. Evaluation of persistent symptoms would include measurement of T3 levels by 21.9% of respondents. Subclinical disease with a TSH 5.0 to 10.0 mU/L would be treated without further justification by 21.3% of respondents, or in the presence of positive thyroid peroxidase antibodies (62.3%), hypothyroid symptoms (60.9%), high low-density lipoprotein (52.9%), or goiter (46.6%). The TSH target for a newly pregnant patient was2.5 mU/L for 96.1% of respondents, with 63.5% preferring a TSH target1.5 mU/L. Thyroidhormonelevelswouldbecheckedevery4weeksduringpregnancyby67. 7%andevery8weeks by an additional 21.4%. A hypothyroid patient with TSH of 0.5 mU/L who becomes pregnant would receive an immediate L-T4 dose increase by only 36.9% of respondents. Conclusion: The current survey of clinical endocrinologists catalogs current practice patterns in the management of hypothyroidism and demonstrates 1) a nearly exclusive preference for L-T4 alone as initial therapy, 2) the widespread use of age-specific TSH targets for replacement therapy, 3) a low threshold for treating mild thyroid failure, 4) meticulous attention to TSH targets in the pregnant and prepregnant woman, and 5) a highly variable approach to both the rate and means of restoring euthyroidism for overt disease. Both alignment and focal divergence from recent CPGs are demonstrated.