Appropriateness of Levothyroxine Prescription: A Multicenter Retrospective Study
Ivan Nicolas Ayala, Cristian Soto Jacome, David Toro-Tobon, Elizabeth Golembiewski, Andrea E Garcia Bautista, Jessica Hidalgo, Sandra Cordova-Madera, Raghda Al Anbari, Jessica R Sohn, Naykky Singh Ospina, Spyridoula Maraka, Marina Joseph, Juan P Brito- Biochemistry (medical)
- Clinical Biochemistry
- Endocrinology
- Biochemistry
- Endocrinology, Diabetes and Metabolism
Abstract
Background
Levothyroxine is one of the most prescribed medications in the United States. This study explores the appropriateness of levothyroxine prescriptions.
Methods
A retrospective multicenter study conducted on adult patients who were prescribed levothyroxine for the first time between 2007 and 2020 within 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 non-evidence based (NEB, not clinically supported).
Results
977 participants were included. The mean age was 55 years old (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 thyroid stimulating hormone (TSH) value of < 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 non-confirmed subclinical hypothyroidism with TSH ≥ 10 mIU/L (no confirmatory testing) (51/118, 43%). In multivariate analysis, being female (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.