Juan P Brito1, Yihong Deng2, Joseph S Ross3,4,5, Nam Hee Choi6, David J Graham7, Yandong Qiang7, Elena Rantou6, Zhong Wang8, Liang Zhao8, Nilay D Shah9, Kasia J Lipska5,10. 1. Division of Endocrinology, Diabetes, Metabolism, Nutrition, Department of Internal Medicine, Mayo Clinic, Rochester, MN, USA. brito.juan@mayo.edu. 2. Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery, Mayo Clinic, Rochester, MN, USA. 3. Section of General Internal Medicine and the National Clinician Scholars Program, Yale School of Medicine, New Haven, CT, USA. 4. Department of Health Policy and Management, Yale School of Public Health, New Haven, CT, USA. 5. Center for Outcomes Research and Evaluation, Yale-New Haven Hospital, New Haven, CT, USA. 6. Office of Biostatistics, Office of Translational Sciences, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, White Oak, MD, USA. 7. Office of Surveillance and Epidemiology, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, White Oak, MD, USA. 8. Office of Research and Standards, Office of Generic Drugs, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, White Oak, MD, USA. 9. Delta Airlines, Atlanta, GA, USA. 10. Section of Endocrinology, Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA.
Abstract
IMPORTANCE: Some practice guidelines warn against generic L-thyroxine preparation switching. OBJECTIVE: To examine the rates of generic L-thyroxine preparation switching within one year of initiating L-thyroxine, and to examine factors associated with switching. DESIGN AND SETTING: Retrospective study using national data from a large administrative claims database from January 2008 through November 2018. PATIENTS: Medicare or commercially insured adults (≥18 years) who filled a generic L-thyroxine preparation. MAIN OUTCOME MEASURES: At least one switch from one generic L-thyroxine preparation to another within 1 year of L-thyroxine initiation defined by prescription fills. RESULTS: From January 2008 to November 2018, we included 483,390 patients who initiated generic L-thyroxine: mean (SD) age was 61.4 years (15.2), 75.2% were female, 72.6% were white. Within 1 year of initiating therapy, 98,013 (20%) switched to another L-thyroxine generic preparation at least once. In a multivariate logistic regression analysis, factors associated with switching included the number of pharmacies visited to fill L-thyroxine (>2 vs 1 adjusted OR [aOR] 7.15, 95% confidence interval [CI] 6.97-7.34), age ≥75 vs. <45 years (aOR 1.29, 95% CI 1.26-1.33), history of thyroid surgery (aOR 1.22, 95% CI 1.13-1.31), and first L-thyroxine fill date in 2018 vs. 2008 (aOR 3.32, 95% CI 3.14-3.51). CONCLUSIONS AND RELEVANCE: One in five patients switched among generic L-thyroxine manufacturers within one year of treatment initiation. Generic L-thyroxine switching occurred more often when more pharmacies were used to fill L-thyroxine. Given existing guideline recommendations, additional studies should clarify the impact of generic L-thyroxine switching on thyroid hormone values.
IMPORTANCE: Some practice guidelines warn against generic L-thyroxine preparation switching. OBJECTIVE: To examine the rates of generic L-thyroxine preparation switching within one year of initiating L-thyroxine, and to examine factors associated with switching. DESIGN AND SETTING: Retrospective study using national data from a large administrative claims database from January 2008 through November 2018. PATIENTS: Medicare or commercially insured adults (≥18 years) who filled a generic L-thyroxine preparation. MAIN OUTCOME MEASURES: At least one switch from one generic L-thyroxine preparation to another within 1 year of L-thyroxine initiation defined by prescription fills. RESULTS: From January 2008 to November 2018, we included 483,390 patients who initiated generic L-thyroxine: mean (SD) age was 61.4 years (15.2), 75.2% were female, 72.6% were white. Within 1 year of initiating therapy, 98,013 (20%) switched to another L-thyroxine generic preparation at least once. In a multivariate logistic regression analysis, factors associated with switching included the number of pharmacies visited to fill L-thyroxine (>2 vs 1 adjusted OR [aOR] 7.15, 95% confidence interval [CI] 6.97-7.34), age ≥75 vs. <45 years (aOR 1.29, 95% CI 1.26-1.33), history of thyroid surgery (aOR 1.22, 95% CI 1.13-1.31), and first L-thyroxine fill date in 2018 vs. 2008 (aOR 3.32, 95% CI 3.14-3.51). CONCLUSIONS AND RELEVANCE: One in five patients switched among generic L-thyroxine manufacturers within one year of treatment initiation. Generic L-thyroxine switching occurred more often when more pharmacies were used to fill L-thyroxine. Given existing guideline recommendations, additional studies should clarify the impact of generic L-thyroxine switching on thyroid hormone values.
Authors: Jacqueline Jonklaas; Antonio C Bianco; Andrew J Bauer; Kenneth D Burman; Anne R Cappola; Francesco S Celi; David S Cooper; Brian W Kim; Robin P Peeters; M Sara Rosenthal; Anna M Sawka Journal: Thyroid Date: 2014-12 Impact factor: 6.568
Authors: Joseph S Ross; Stefanie Rohde; Lindsey Sangaralingham; Juan P Brito; Lauren Choi; Sarah K Dutcher; David J Graham; Marjorie R Jenkins; Kasia J Lipska; Martin Mendoza; Yandong Qiang; Zhong Wang; Yute Wu; Xiaoxi Yao; Nilay D Shah Journal: J Clin Endocrinol Metab Date: 2019-06-01 Impact factor: 5.958
Authors: Hude Quan; Vijaya Sundararajan; Patricia Halfon; Andrew Fong; Bernard Burnand; Jean-Christophe Luthi; L Duncan Saunders; Cynthia A Beck; Thomas E Feasby; William A Ghali Journal: Med Care Date: 2005-11 Impact factor: 2.983
Authors: Paul J Wallace; Nilay D Shah; Taylor Dennen; Paul A Bleicher; Paul D Bleicher; William H Crown Journal: Health Aff (Millwood) Date: 2014-07 Impact factor: 6.301