Appropriateness of Levothyroxine Prescription: A Multicenter Retrospective Study.

CONTEXT: Levothyroxine is one of the most prescribed medications in the United States. OBJECTIVE: This study explores the appropriateness of levothyroxine prescriptions. METHODS: A retrospective multicenter study was conducted on adult patients who were prescribed levothyroxine for the first time between 2017 and 2020 at three academic centers in the United States. We classified each case of levothyroxine initiation into one of three mutually exclusive categories: appropriate (clinically supported), indeterminate (clinically unclear), or nonevidence based (NEB, not clinically supported). RESULTS: A total of 977 participants were included. The mean age was 55 years (SD 19), there was female (69%) and White race predominance (84%), and 44% had possible hypothyroid symptoms. Nearly half of the levothyroxine prescriptions were considered NEB (528, 54%), followed by appropriate (307, 31%) and indeterminate (118, 12%). The most common reason for NEB prescription was an index thyrotropin (TSH) value of less than 10 mIU/L without previous TSH or thyroxine values (131/528, 25%), for appropriate prescription, was overt hypothyroidism (163/307, 53%), and for an indeterminate prescription was a nonconfirmed subclinical hypothyroidism with TSH greater than or equal to 10 mIU/L (no confirmatory testing) (51/118, 43%). In multivariable analysis, being female (odds ratio [OR]: 1.3; 95% CI, 1.0-1.7) and prescription by a primary care provider (OR: 1.5; 95% CI, 1.2-2.0) were associated with NEB prescriptions. CONCLUSION: There is a considerable proportion of NEB levothyroxine prescriptions. These results call for additional research to replicate these findings and to explore the perspective of those prescribing and receiving levothyroxine.

Real Practice Assessment of Persistent Symptoms After Initiation of Levothyroxine.

OBJECTIVE: Levothyroxine (LT4) is the standard treatment for hypothyroidism. However, certain patients experience persistent symptoms even after achieving euthyroid status with LT4 therapy. We aimed to determine the frequency of persistent or new symptoms in patients with hypothyroidism after initiating LT4. METHODS: This retrospective study included patients with hypothyroidism who started on LT4 between January 2017 and December 2019 at Mayo Clinic in Rochester, Minnesota, USA. Five hundred patient charts were randomly selected for review. Patients with at least 1 documented follow-up encounter after LT4 initiation were evaluated for ≤3 follow-up visits regarding their biochemical status and symptoms. RESULTS: We included 356 patients, a majority of whom were female (66.6%), white (92.3%), and obese (71.9%), with an average age of 59.5 years. At the baseline visit, approximately one-half of the patients (177/356, 47.7%) reported hypothyroid symptoms, with fatigue being the most common symptom. During the follow-up periods, we observed that 17.8% (28/157), 17.9% (19/106), and 19.3% (11/57) of patients had normal thyroid stimulating hormone (TSH) values but persistent symptoms, while 12.3% (19/156), 19.9% (16/107), and 8.9% (5/56) had normal TSH values but new symptoms. Overall, during each respective follow-up period, 26.7% (42/157), 27.3% (29/106), and 28% (16/57) of patients experienced persistent or new symptoms alongside normal TSH values, with fatigue being the most constant symptom. CONCLUSION: Our findings indicate that approximately 1 in every 4 patients with hypothyroidism receiving LT4 therapy and achieving normal TSH levels experience persistent or new hypothyroid symptoms. The cause of these symptoms remains unclear, emphasizing the need for a better understanding of their underlying causes and the development of effective management strategies.

Drivers of Thyroid Ultrasound Use: A Retrospective Observational Study.

OBJECTIVE: Excessive use of thyroid ultrasound (TUS) contributes to the overdiagnosis of thyroid nodules and thyroid cancer. In this study, we evaluated drivers of and clinical trajectories following TUS orders. METHODS: We conducted a retrospective review of 500 adult patients who underwent an initial TUS between 2015 and 2017 at Mayo Clinic in Rochester, MN. A framework was employed to classify the indication for TUS, and it was characterized as inappropriate when ordered without a guideline-based indication. Medical records were reviewed for up to 12 months following the TUS, and clinical outcomes were evaluated. RESULTS: The mean age mean age (SD) was 53.6 years (16.6), 63.8% female, and 86.6% white. TUS orders were triggered by incidental findings on unrelated imaging (31.6%), thyroid symptoms (20.4%), thyroid abnormalities on routine physical examination (17.2%), and thyroid dysfunction workup (11.8%). In females and males, the most common reason were incidental findings on imaging (female, 91/319, 28.5% and male, 67/181, 37.0%). In primary care practice, TUS orders were mostly triggered by symptoms (71/218, 32.5%), while thyroid dysfunction workup was the primary reason in endocrinology (28/100, 28.0%). We classified 11.2% (56/500) TUS orders as likely to have been ordered inappropriately based on current guidelines. Finally, 119 patients (119/500, 23.8%) had a thyroid biopsy with 11.8% had thyroid cancer (14/119. 11.8%). CONCLUSIONS: Incidental findings on imaging, symptoms, and routine physical exam findings in asymptomatic patients were the most prevalent drivers of TUS. Furthermore, 1 in 10 TUS were likely inappropriately ordered based on current practice guidelines.