BACKGROUND: Subclinical thyroid disease is common; however, screening recommendations using serum thyrotropin (TSH) level determinations are controversial. METHODS: To study the use of serum TSH by primary care physicians and define populations at risk for having an abnormal TSH level at follow-up, based on initial TSH levels, we conducted an observational study of a large health care database in the setting of a health management organization. All outpatients without thyroid disease or pregnancy or taking medication that may alter thyroid function in whom the TSH level was measured in 2002 and during 5-year follow-up were included in this study. Repeated TSH level determinations were compared with the initial TSH level values. RESULTS: In 422 242 patients included, 95% of the initial serum TSH concentrations were within normal limits (0.35-5.5 mIU/L), 1.2% were decreased (<0.35 mIU/L), 3.0% were elevated (>5.5 to <or=10 mIU/L) and 0.7% were highly elevated (>10 mIU/L). In 346 549 patients without thyroid-specific medications, the TSH levels became normal in 27.2%, 62.1%, and 51.2%, whose initial serum TSH level was highly elevated, elevated, and decreased, respectively, and remain normal in 98% of the patients with normal initial TSH levels. When the initial serum TSH level was elevated, patients in the highest quintile of this group, who had a shorter interval between the first and second measurements, had a higher probability of a second highly elevated TSH concentration (P < .001). CONCLUSIONS: When the serum TSH level is normal, the likelihood of an abnormal level within 5 years is low (2%). More than 50% of patients with elevated or decreased serum TSH levels have normal levels in repeated measurements.
BACKGROUND: Subclinical thyroid disease is common; however, screening recommendations using serum thyrotropin (TSH) level determinations are controversial. METHODS: To study the use of serum TSH by primary care physicians and define populations at risk for having an abnormal TSH level at follow-up, based on initial TSH levels, we conducted an observational study of a large health care database in the setting of a health management organization. All outpatients without thyroid disease or pregnancy or taking medication that may alter thyroid function in whom the TSH level was measured in 2002 and during 5-year follow-up were included in this study. Repeated TSH level determinations were compared with the initial TSH level values. RESULTS: In 422 242 patients included, 95% of the initial serum TSH concentrations were within normal limits (0.35-5.5 mIU/L), 1.2% were decreased (<0.35 mIU/L), 3.0% were elevated (>5.5 to <or=10 mIU/L) and 0.7% were highly elevated (>10 mIU/L). In 346 549 patients without thyroid-specific medications, the TSH levels became normal in 27.2%, 62.1%, and 51.2%, whose initial serum TSH level was highly elevated, elevated, and decreased, respectively, and remain normal in 98% of the patients with normal initial TSH levels. When the initial serum TSH level was elevated, patients in the highest quintile of this group, who had a shorter interval between the first and second measurements, had a higher probability of a second highly elevated TSH concentration (P < .001). CONCLUSIONS: When the serum TSH level is normal, the likelihood of an abnormal level within 5 years is low (2%). More than 50% of patients with elevated or decreased serum TSH levels have normal levels in repeated measurements.
Authors: Richard Birtwhistle; Kate Morissette; James A Dickinson; Donna L Reynolds; Marc T Avey; Francesca Reyes Domingo; Rachel Rodin; Brett D Thombs Journal: CMAJ Date: 2019-11-18 Impact factor: 8.262
Authors: J Todd Kuenstner; William Chamberlin; Saleh A Naser; Michael T Collins; Coad Thomas Dow; John M Aitken; Stuart Weg; Grzegorz Telega; Kuruvilla John; David Haas; Torsten M Eckstein; Maher Kali; Christine Welch; Thomas Petrie Journal: World J Gastroenterol Date: 2015-04-07 Impact factor: 5.742
Authors: Peter N Taylor; Diana Albrecht; Anna Scholz; Gala Gutierrez-Buey; John H Lazarus; Colin M Dayan; Onyebuchi E Okosieme Journal: Nat Rev Endocrinol Date: 2018-03-23 Impact factor: 43.330