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Premawardhana LD, Taylor PN, Okosieme OE, Adlan MA, Obuobie EK, Dayan CM. Designing a combined liothyronine (LT3), L- thyroxine (LT4) trial in symptomatic hypothyroid subjects on LT4 - the importance of patient selection, choice of LT3 and trial design. Front Endocrinol (Lausanne) 2023; 14:1282608. [PMID: 38034018 PMCID: PMC10687631 DOI: 10.3389/fendo.2023.1282608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 10/23/2023] [Indexed: 12/02/2023] Open
Abstract
Approximately 10%-15% of subjects with hypothyroidism on L-thyroxine (LT4) alone have persistent symptoms affecting their quality of life (QoL). Although the cause is unclear, there is evidence that "tissue T3 lack" may be responsible. If so, combining liothyronine (LT3) with LT4 would be helpful. However, randomized controlled trials (RCT), have not established greater efficacy for the LT3 + LT4 combination in these subjects than for LT4 alone. While the trial design may have been responsible, the use of unphysiological, short-acting LT3 preparations and non-thyroid-specific patient-reported outcome measures (PROMs) may have contributed. We recommend attention to the following aspects of trial design for future RCTs of LT3 + LT4 compared to LT4 alone: (a) Subject selection-(i) measurable symptoms (disadvantages should be recognized); (ii) using a validated thyroid specific PROM such as ThyPRO39 or the Composite scale derived from it; (iii) those taking over 1.2 μg/day or 100 μg/day (for pragmatic reasons) of LT4 defining a population likely without intrinsic thyroid activity who depend on exogenous LT4; (iv) recruiting a preponderance of subjects with autoimmune thyroiditis increasing generalisability; and (v) those with a high symptom load with a greater response to combination therapy e.g. those with the deiodinase 2 polymorphism. (b) The use of physiological LT3 preparations producing pharmacokinetic similarities to T3 profiles in unaffected subjects: two long-acting LT3 preparations are currently available and must be tested in phase 2b/3 RCTs. (c) The superiority of a crossover design in limiting numbers and costs while maintaining statistical power and ensuring that all subjects experienced the investigative medication.
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Affiliation(s)
- Lakdasa D. Premawardhana
- Thyroid Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Heath Park, Cardiff, United Kingdom
| | - Peter Nicholas Taylor
- Thyroid Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Heath Park, Cardiff, United Kingdom
| | - Onyebuchi E. Okosieme
- Thyroid Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Heath Park, Cardiff, United Kingdom
| | - Mohamed A. Adlan
- Section of Endocrinology, Ysbyty Ystrad Fawr and Royal Gwent Hospitals, Aneurin Bevan University Health Board, Newport, United Kingdom
| | - Emmanuel K. Obuobie
- Section of Endocrinology, Ysbyty Ystrad Fawr and Royal Gwent Hospitals, Aneurin Bevan University Health Board, Newport, United Kingdom
| | - Colin Mark Dayan
- Thyroid Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Heath Park, Cardiff, United Kingdom
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Biondi B, Celi FS, McAninch EA. Critical Approach to Hypothyroid Patients With Persistent Symptoms. J Clin Endocrinol Metab 2023; 108:2708-2716. [PMID: 37071856 PMCID: PMC10686697 DOI: 10.1210/clinem/dgad224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 04/07/2023] [Accepted: 04/13/2023] [Indexed: 04/20/2023]
Abstract
Hypothyroidism is a common condition, and numerous studies have been published over the last decade to assess the potential risks associated with this disorder when inappropriately treated. The standard of care for treatment of hypothyroidism remains levothyroxine (LT4) at doses to achieve biochemical and clinical euthyroidism. However, about 15% of hypothyroid patients experience residual hypothyroid symptoms. Some population-based studies and international population-based surveys have confirmed dissatisfaction with LT4 treatment in some hypothyroid patients. It is well established that hypothyroid patients treated with LT4 exhibit higher serum thyroxine:triiodothyronine ratios and can have a persistent increase in cardiovascular risk factors. Moreover, variants in deiodinases and thyroid hormone transporter genes have been associated with subnormal T3 concentrations, persistent symptoms in LT4-treated patients, and improvement in response to the addition of liothyronine to LT4 therapy. The American (ATA) and European Thyroid Association (ETA) guidelines have recently evolved in their recognition of the potential limitations of LT4. This shift is reflected in prescribing patterns: Physicians' use of combination therapy is prevalent and possibly increasing. Randomized clinical trials have recently been published and, while they have found no improvement in treating hypothyroid patients, a number of important limitations did not allow generalizability. Meta-analyses have reported a preference rate for combination therapy in 46.2% hypothyroid patients treated with LT4. To promote discussions about an optimal study design, the ATA, ETA, and British Thyroid Association have recently published a consensus document. Our study provides a useful counterpoint on the controversial benefits of treating hypothyroid patients with combination therapy.
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Affiliation(s)
- Bernadette Biondi
- Division of Internal Medicine and Cardiovascular Endocrinology, Department of Clinical Medicine and Surgery, University Federico II of Naples, 80131 Naples, Italy
| | - Francesco S Celi
- Division of Endocrinology and Metabolism, Department of Medicine UConn Health, Farmington, CT 06030-8075, USA
| | - Elizabeth A McAninch
- Division of Endocrinology, Metabolism and Gerontology, Stanford University Medical Center, Stanford, CA 94305, USA
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Jonklaas J. Is euthyroidism within reach for all? Expert Rev Endocrinol Metab 2023; 18:455-458. [PMID: 37811647 DOI: 10.1080/17446651.2023.2267120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Accepted: 10/02/2023] [Indexed: 10/10/2023]
Affiliation(s)
- Jacqueline Jonklaas
- Division of Endocrinology, Georgetown University, Washington, DC, United States
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Ahluwalia R, Baldeweg SE, Boelaert K, Chatterjee K, Dayan C, Okosieme O, Priestley J, Taylor P, Vaidya B, Zammitt N, Pearce SH. Use of liothyronine (T3) in hypothyroidism: Joint British Thyroid Association/Society for endocrinology consensus statement. Clin Endocrinol (Oxf) 2023; 99:206-216. [PMID: 37272400 DOI: 10.1111/cen.14935] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 05/18/2023] [Accepted: 05/19/2023] [Indexed: 06/06/2023]
Abstract
Persistent symptoms in patients treated for hypothyroidism are common. Despite more than 20 years of debate, the use of liothyronine for this indication remains controversial, as numerous randomised trials have failed to show a benefit of treatment regimens that combine liothyronine (T3) with levothyroxine over levothyroxine monotherapy. This consensus statement attempts to provide practical guidance to clinicians faced with patients who have persistent symptoms during thyroid hormone replacement therapy. It applies to non-pregnant adults and is focussed on care delivered within the UK National Health Service, although it may be relevant in other healthcare environments. The statement emphasises several key clinical practice points for patients dissatisfied with treatment for hypothyroidism. Firstly, it is important to establish a diagnosis of overt hypothyroidism; patients with persistent symptoms during thyroid hormone replacement but with no clear biochemical evidence of overt hypothyroidism should first have a trial without thyroid hormone replacement. In those with established overt hypothyroidism, levothyroxine doses should be optimised aiming for a TSH in the 0.3-2.0 mU/L range for 3 to 6 months before a therapeutic response can be assessed. In some patients, it may be acceptable to have serum TSH below reference range (e.g. 0.1-0.3 mU/L), but not fully suppressed in the long term. We suggest that for some patients with confirmed overt hypothyroidism and persistent symptoms who have had adequate treatment with levothyroxine and in whom other comorbidities have been excluded, a trial of liothyronine/levothyroxine combined therapy may be warranted. The decision to start treatment with liothyronine should be a shared decision between patient and clinician. However, individual clinicians should not feel obliged to start liothyronine or to continue liothyronine medication provided by other health care practitioners or accessed without medical advice, if they judge this not to be in the patient's best interest.
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Affiliation(s)
- Rupa Ahluwalia
- Department of Diabetes & Endocrinology, Norfolk and Norwich University Hospitals NHS Trust, Norwich, UK
| | - Stephanie E Baldeweg
- Department of Diabetes & Endocrinology, University College London, London, UK
- Centre for Obesity & Metabolism, Department of Experimental & Translational Medicine, Division of Medicine, University College London Hospitals, London, UK
- The RCP Joint Specialties Committee and The Clinical Committee, Society for Endocrinology, Bristol, UK
| | - Kristien Boelaert
- Institute for Applied Health Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Krishna Chatterjee
- Wellcome-MRC Institute of Metabolic Sciences, University of Cambridge, Cambridge, UK
| | - Colin Dayan
- Thyroid Research Group, Heath Park, Cardiff University, Cardiff, UK
| | | | | | - Peter Taylor
- Thyroid Research Group, Heath Park, Cardiff University, Cardiff, UK
| | - Bijay Vaidya
- Department of Endocrinology, Royal Devon University Hospital |University of Exeter Medical School, Exeter, UK
| | - Nicola Zammitt
- Edinburgh Centre for Endocrinology and Diabetes, Royal Infirmary of Edinburgh, Edinburgh, UK
| | - Simon H Pearce
- BioMedicine West, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
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Hennessey JV. Levothyroxine Monotherapy: What Works Better for the Individual With Hypothyroidism? Endocr Pract 2023; 29:572-580. [PMID: 37419564 DOI: 10.1016/j.eprac.2022.12.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 12/16/2022] [Indexed: 07/09/2023]
Abstract
OBJECTIVE I explore objective data not supporting the addition of liothyronine (medication) (LT3) to levothyroxine (medication) (LT4) in patients with hypothyroidism. Accurate identification of patients with symptomatic (almost exclusively overt) hypothyroidism is important in evaluating clinical outcomes of therapies. Recent studies have documented that nearly a third of individuals who are offered thyroid hormone are euthyroid at the time of initiation. Additionally, others are clinically diagnosed without biochemical confirmation, so a sizable proportion of those started on LT4 are not hypothyroid. The assumption that nonhypothyroid symptoms will resolve with LT4 is problematic. The true underlying cause of these symptoms remains unidentified and untreated. METHODS In a narrative fashion I will review the positive predictive value of and correlation of symptoms consistent with hypothyroidism and confirmed hypothyroidism likely to favorably respond to thyroid hormone replacement. RESULTS Following a review of the reliability of thyroid-stimulating hormone (TSH) in predicting a euthyroid state, the correlation of circulating triiodothyronine (serum measurement) (T3) levels with symptoms and predictive value of T3 to forecast the outcome of adding LT3 to LT4 will be reviewed. The utility of striving for high, middle, or low TSH set points within the expected range to predict changes in clinical quality of life and the ability of blinded patients to sense subtle differences along this spectrum will be documented. In addition, the clinical impact of single nucleotide polymorphisms in the type 2 deiodinase gene will be reviewed. Finally, the overall satisfaction of selected patients with their thyroid hormone treatments will be outlined and preferences for T3-containing treatments from blinded studies will be summarized. CONCLUSION Basing thyroid hormone treatment decisions on patient symptoms likely results in missed diagnoses We should encourage primary care physicians to assess a differential diagnosis, exclude other diagnoses, and not assume a thyroid etiology when TSH is normal. Modifying treatment to a particular TSH target or adjusting based on a low T3 level does not seem to enhance patient outcomes. Finally, pending further trials of "symptomatic" participants, using sustained release LT3 to mimic normal physiology, and including monocarboxylate 10 transporter and Type 2 deiodinase polymorphisms and objective outcomes, I will continue to depend on therapy with LT4 monotherapy and seek alternative explanations for my patients' nonspecific symptoms.
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Affiliation(s)
- James V Hennessey
- Department of Medicine, Harvard Medical School, Boston, Massachusetts.
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Perros P, Van Der Feltz-Cornelis C, Papini E, Nagy EV, Weetman AP, Hegedüs L. The enigma of persistent symptoms in hypothyroid patients treated with levothyroxine: A narrative review. Clin Endocrinol (Oxf) 2023; 98:461-468. [PMID: 33783849 DOI: 10.1111/cen.14473] [Citation(s) in RCA: 32] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Revised: 03/24/2021] [Accepted: 03/25/2021] [Indexed: 12/19/2022]
Abstract
A significant minority of patients with hypothyroidism report persistent symptoms despite achieving normal thyroid biochemistry after levothyroxine (L-T4) replacement. Four principal lines of thinking, which are not mutually exclusive, may explain this enigma. The 'low tissue liothyronine hypothesis' emphasizes the potential imperfections of L-T4 replacement therapy that may lead to hypothyroidism in some tissues such as the brain, while others (eg hypothalamus) are euthyroid. The 'Somatic Symptom and Related Disorders hypothesis' draws attention to an incidental coexistence of a diagnosis of Somatic Symptom and Related Disorders in patients with treated hypothyroidism. The 'autoimmune neuroinflammation hypothesis' highlights the potential consequences of inflammatory mediators due to thyroid autoimmunity (the commonest cause of hypothyroidism) on the brain. The 'comorbidities and psychosocial hypothesis' implicates a variety of physical and psychosocial factors that have been noted to be associated with a diagnosis of hypothyroidism, which may be primarily the cause of persistent complaints. Over the past twenty years, a great deal of time and effort has been expended pursuing the 'low tissue liothyronine hypothesis', which has failed to yield results that translate to patient benefits. This has skewed the balance in clinical practice, in favour of pursuing answers relating to L-T4 and liothyronine combination treatment, while the alternative explanations have been downplayed and potentially useful interventions have been given insufficient attention.
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Affiliation(s)
- Petros Perros
- Department of Endocrinology, Royal Victoria Infirmary, Newcastle upon Tyne, UK
| | | | - Enrico Papini
- Department of Endocrinology and Metabolism, Regina Apostolorum Hospital, Albano, Rome, Italy
| | - Endre V Nagy
- Division of Endocrinology, Department of Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Anthony P Weetman
- Department of Oncology and Metabolism, University of Sheffield, Sheffield, UK
| | - Laszlo Hegedüs
- Department of Endocrinology, Odense University Hospital, Odense, Denmark
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Liu H, Li W, Zhang W, Sun S, Chen C. Levothyroxine: Conventional and novel drug delivery formulations. Endocr Rev 2022; 44:393-416. [PMID: 36412275 PMCID: PMC10166268 DOI: 10.1210/endrev/bnac030] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 10/18/2022] [Accepted: 11/17/2022] [Indexed: 11/23/2022]
Abstract
Despite the fact that levothyroxine is one of the most prescribed medications in the world, its bioavailability has been reported to be impaired by many factors, including interfering drugs or foods and concomitant diseases, and persistent hypothyroidism with a high dose of levothyroxine is thus elicited. Persistent hypothyroidism can also be induced by noninterchangeability between formulations and poor compliance. To address these issues, some strategies have been developed. Novel formulations (liquid solutions and soft-gel capsules) have been designed to eliminate malabsorption. Some other delivery routes (injections, suppositories, sprays, and sublingual and transdermal administrations) are aimed at circumventing different difficulties in dosing, such as thyroid emergencies and dysphagia. Moreover, nanomaterials have been used to develop delivery systems for the sustained release of levothyroxine to improve patient compliance and reduce costs. Some delivery systems encapsulating nanoparticles show promising release profiles. In this review, we first summarize the medical conditions that interfere with the bioavailability of oral levothyroxine and discuss the underlying mechanisms and treatments. The efficacy of liquid solutions and soft-gel capsules are systematically evaluated. We further summarize the novel delivery routes for levothyroxine and their possible applications. Nanomaterials in the levothyroxine field are then discussed and compared based on their load and release profile. We hope the article provides novel insights into the drug delivery of levothyroxine.
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Affiliation(s)
- Hanqing Liu
- Department of Breast and Thyroid Surgery, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei, People's Republic of China
| | - Wei Li
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430060, Hubei, People's Republic of China
| | - Wen Zhang
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430060, Hubei, People's Republic of China
| | - Shengrong Sun
- Department of Breast and Thyroid Surgery, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei, People's Republic of China
| | - Chuang Chen
- Department of Breast and Thyroid Surgery, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei, People's Republic of China
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Lan H, Wen J, Mao Y, Huang H, Chen G, Lin W. Combined T4 + T3 therapy versus T4 monotherapy effect on psychological health in hypothyroidism: A systematic review and meta-analysis. Clin Endocrinol (Oxf) 2022; 97:13-25. [PMID: 35445422 DOI: 10.1111/cen.14742] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 04/06/2022] [Accepted: 04/16/2022] [Indexed: 11/28/2022]
Abstract
PURPOSE To evaluate whether T4 + T3 combination therapy had advantages in improving psychological health compared with T4 monotherapy. METHODS We searched PubMed, Embase, Cochrane Library, and Web of Science from January 2000 to March 2021, and updated in September 2021. The inclusion criteria (prospective study, published in English, had a T4 + T3 combination therapy test group and a T4 monotherapy control group, patients aged ≥18 years and with overt primary hypothyroidism, and published after January 2000) were applied by two reviewers; any disagreement was resolved by a third reviewer. The two reviewers independently extracted data using a standard data form and assessed the risk of bias using the Cochrane risk of bias tool. Coprimary outcomes included the psychological health measures of depression, fatigue, pain, anxiety and anger, measured using validated and reliable instruments. RESULTS Eighteen of 2029 studies (883 patients) were included in the meta-analysis. No significant difference was found between T4 + T3 combination therapy and T4 monotherapy with regard to depression (standardized mean difference [SMD]: -0.06, 95% confidence interval [CI]: -0.18; 0.07), fatigue (SMD: 0.06, 95% CI: -0.13; 0.26), pain (SMD: -0.01, 95% CI: -0.24; 0.22), anxiety (SMD: 0.01, 95% CI: -0.15; 0.17) and anger (SMD: 0.05, 95% CI: -0.15; 0.24). Methodological heterogeneity had no influence on the results. The patients preferred combination therapy significantly. CONCLUSIONS Compared with T4 monotherapy, T4 + T3 combination therapy had no significant advantage in improving psychological health. For patients who are unsatisfied with LT4 monotherapy, the patient and the physician should make a joint decision concerning therapy.
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Affiliation(s)
- Huiyu Lan
- Department of Endocrinology, Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, Fuzhou, Fujian, China
| | - Junping Wen
- Department of Endocrinology, Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, Fuzhou, Fujian, China
| | - Yaqian Mao
- Department of Endocrinology, Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, Fuzhou, Fujian, China
| | - Huibin Huang
- Department of Endocrinology, Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, Fuzhou, Fujian, China
| | - Gang Chen
- Department of Endocrinology, Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, Fuzhou, Fujian, China
- Fujian Provincial Key Laboratory of Medical Analysis, Fujian Academy of Medical, Fuzhou, Fujian, China
| | - Wei Lin
- Department of Endocrinology, Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, Fuzhou, Fujian, China
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Jonklaas J. Role of Levothyroxine/Liothyronine Combinations in Treating Hypothyroidism. Endocrinol Metab Clin North Am 2022; 51:243-263. [PMID: 35662440 DOI: 10.1016/j.ecl.2021.12.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Diverse causes potentially underlie decreased quality of life in biochemically euthyroid patients treated for hypothyroidism with levothyroxine. Once these contributing factors are addressed, if symptoms persist, there may be benefit to personalized use of combination therapy adding liothyronine. This approach should be carefully monitored: avoiding overtreatment and ensuring that therapy is only continued if it improves patient-reported quality of life. Most randomized clinical trials have not shown benefits, perhaps because of not targeting the most symptomatic patients. Sustained-release liothyronine preparations may soon be available for optimally designed studies assessing whether combination therapy provides superior therapy for hypothyroidism in select patients.
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Affiliation(s)
- Jacqueline Jonklaas
- Division of Endocrinology, Georgetown University, Washington, DC 20007, USA.
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10
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Abstract
Hypothyroidism is a common endocrinopathy, and levothyroxine is frequently prescribed. Despite the basic tenets of initiating and adjusting levothyroxine being agreed on, there are many nuances and complexities to consistently maintaining euthyroidism. Understanding the impact of patient weight and residual thyroid function on initial levothyroxine dosage and consideration of age, comorbidities, thyrotropin goal, life stage, and quality of life as levothyroxine is adjusted can be challenging and continually evolving. Because levothyroxine is a lifelong medication, it is important to avoid risks from periods of overtreatment or undertreatment. For the subset of patients not restored to baseline health with levothyroxine, causes arising from all aspects of the patient's life (coexistent medical conditions, stressors, lifestyle, psychosocial factors) should be broadly considered. If such factors do not appear to be contributing, and biochemical euthyroidism has been successfully maintained, there may be benefit to a trial of combination therapy with levothyroxine and liothyronine. This is not supported by the majority of randomized clinical trials, but may be supported by other studies providing lower-quality evidence and by animal studies. Given this discrepancy, it is important that any trial of combination therapy be continued only as long as a patient benefit is being enjoyed. Monitoring for adverse effects, particularly in older or frail individuals, is necessary and combination therapy should not be used during pregnancy. A sustained-release liothyronine preparation has completed phase 1 testing and may soon be available for better designed and powered studies assessing whether combination therapy provides superior therapy for hypothyroidism.
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Wiersinga WM. T4+T3 Combination Therapy: An Unsolved Problem of Increasing Magnitude and Complexity. Endocrinol Metab (Seoul) 2021; 36:938-951. [PMID: 34587734 PMCID: PMC8566135 DOI: 10.3803/enm.2021.501] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 08/30/2021] [Indexed: 12/29/2022] Open
Abstract
Thyroxine (T4)+triiodothyronine (T3) combination therapy can be considered in case of persistent symptoms despite normal serum thyroid stimulating hormone in levothyroxine (LT4)-treated hypothyroid patients. Combination therapy has gained popularity in the last two decades, especially in countries with a relatively high gross domestic product. The prevalence of persistent symptoms has also increased; most frequent are complaints about energy levels and fatigue (80% to 90%), weight management (70% to 75%), memory (60% to 80%), and mood (40% to 50%). Pathophysiological explanations for persistent problems are unrealistic patient expectations, comorbidities, somatic symptoms, related disorders (Diagnostic and Statistical Manual of Mental Disorders [DSM-5]), autoimmune neuroinflammation, and low tissue T3. There is fair circumstantial evidence for the latter cause (tissue and specifically brain T3 content is normalized by T4+T3, not by T4 alone), but the other causes are viewed as more relevant in current practice. This might be related to the 'hype' that has emerged surrounding T4+T3 therapy. Although more and better-designed trials are needed to validate the efficacy of T4+T3 combination, the management of persistent symptoms should also be directed towards alternative causes. Improving the doctor-patient relationship and including more and better information is crucial. For example, dissatisfaction with the outcomes of T4 treatment for subclinical hypothyroidism can be anticipated as recent trials have demonstrated that LT4 is hardly effective in improving symptoms associated with subclinical hypothyroidism.
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Affiliation(s)
- Wilmar M Wiersinga
- Department of Endocrinology, Amsterdam University Medical Center, Academic Medical Center, Amsterdam, the Netherlands
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12
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Dora JM, Scheffel RS, Maia AL. T3 therapy for hypothyroidism: choosing wisely still requires careful bench to bedside translation. ARCHIVES OF ENDOCRINOLOGY AND METABOLISM 2021; 65:394-395. [PMID: 34191412 PMCID: PMC10065335 DOI: 10.20945/2359-3997000000377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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13
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Planck T, Hedberg F, Calissendorff J, Nilsson A. Liothyronine Use in Hypothyroidism and its Effects on Cancer and Mortality. Thyroid 2021; 31:732-739. [PMID: 33040688 DOI: 10.1089/thy.2020.0388] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Background: The prescription of liothyronine (LT3) to treat hypothyroidism is increasing worldwide; however, the long-term safety of LT3 use has yet to be determined. Previous studies have suggested a possible association between LT3 use and breast cancer. The aim of this study was to examine the effects of LT3 use on cancer incidence and mortality. Methods: Our sample included the full adult population of individuals living in Sweden with at least three purchases of thyroid hormone therapy between July 2005 and December 2017. Individual-level data on drug purchases were linked to registry data on cancer incidence and mortality. There were 575,461 individuals with at least three purchases, of which 11,147 had made at least three purchases of LT3, including combinations of levothyroxine (LT4) and LT3. Individuals were followed for a median follow-up time of 8.1 years. We applied Cox regression with a time-varying exposure variable, comparing LT3 users (individuals with at least three cumulative purchases of LT3) with LT4-only users (the rest). Outcomes included breast cancer incidence, any cancer incidence, all-cause mortality, any cancer mortality, and breast cancer mortality. We adjusted for age, sex, previous thyroid cancer, previous other cancer, use of antithyroid preparations, use of sex hormones, and dose in multivariate analyses. Results: Multivariate analyses produced a hazard ratio of 0.93 (95% confidence interval [0.75-1.15]) for breast cancer incidence (only females), 0.97 (0.87-1.08) for any cancer incidence, 0.69 (0.61-0.77) for all-cause mortality, 0.78 (0.62-0.98) for any cancer mortality, and 0.91 (0.50-1.66) for breast cancer mortality (only females). Conclusions: In this large, Swedish, long-term registry-based study, the use of LT3 did not lead to increased breast cancer incidence, any cancer incidence, all-cause mortality, any cancer mortality, or breast cancer mortality compared with LT4 use. Somewhat surprisingly, there was evidence of lower mortality in LT3 users in models adjusting for dose, potentially an artifact of underlying associations between dose and health status/diagnosis.
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Affiliation(s)
- Tereza Planck
- Department of Endocrinology, Skåne University Hospital, Malmö, Sweden
- Department of Clinical Sciences Malmö, Lund University, Lund, Sweden
| | - Fredric Hedberg
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Endocrinology, Metabolism and Diabetes, Karolinska University Hospital, Stockholm, Sweden
| | - Jan Calissendorff
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Endocrinology, Metabolism and Diabetes, Karolinska University Hospital, Stockholm, Sweden
| | - Anton Nilsson
- EPI@LUND, Division of Occupational and Environmental Medicine, Lund University, Lund, Sweden
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Mitchell AL, Hegedüs L, Žarković M, Hickey JL, Perros P. Patient satisfaction and quality of life in hypothyroidism: An online survey by the british thyroid foundation. Clin Endocrinol (Oxf) 2021; 94:513-520. [PMID: 32978985 DOI: 10.1111/cen.14340] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 08/16/2020] [Accepted: 09/09/2020] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Dissatisfaction with treatment and impaired quality of life (QOL) are reported among people with treated hypothyroidism. We aimed to gain insight into this. DESIGN AND PATIENTS We conducted an online survey of individuals with self-reported hypothyroidism. RESULTS Nine hundred sixty-nine responses were analysed. Dissatisfaction with treatment was common (77.6%), and overall QOL scores were low. Patient satisfaction did not correlate with type of thyroid hormone treatment, but treatment with combination levothyroxine (L-T4) and liothyronine (L-T3) or with desiccated thyroid extract (DTE) was associated with significantly better reported QOL than L-T4 or L-T3 monotherapies (P < .001); however, multivariate analysis inclusive of other clinical parameters failed to confirm an association between type of thyroid hormone treatment and QOL or satisfaction. Multivariate analysis showed positive correlations between satisfaction and age (P = .026), male gender (P = .011), being under the care of a thyroid specialist (P < .001), family doctor (GP) prescribing DTE or L-T4 + L-T3 or L-T3 (P < .001) and being well informed about hypothyroidism (P < .001); negative correlations were observed between satisfaction and negative experiences with L-T4 (P < .001) and expectations for more support from the GP (P < .001), for L-T4 to resolve all symptoms (P = .004), and to be referred to a thyroid specialist (P < .001). For QOL, positive correlations were with male gender (P = .011) and duration of hypothyroidism (P = .002); negative correlations were with age (P = .027), visiting the GP more than 3 times before diagnosis (P < .001), sourcing DTE or L-T3 independently (P = .014), negative experiences with L-T4 (P = .013), having expectations for L-T4 to resolve all symptoms (P < .001) and of more support from the GP (P = .006). CONCLUSIONS Multiple parameters including prior healthcare experiences and expectations influence satisfaction with hypothyroidism treatment and QOL. Focusing on enhancing the patient experience and clarifying expectations at diagnosis may improve satisfaction and QOL.
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Affiliation(s)
- Anna L Mitchell
- Department of Endocrinology, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
- British Thyroid Foundation, Harrogate, UK
| | - Laszlo Hegedüs
- Department of Endocrinology, Odense University Hospital, Odense, Denmark
| | - Miloš Žarković
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | | | - Petros Perros
- Department of Endocrinology, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
- British Thyroid Foundation, Harrogate, UK
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Jonklaas J, Bianco AC, Cappola AR, Celi FS, Fliers E, Heuer H, McAninch EA, Moeller LC, Nygaard B, Sawka AM, Watt T, Dayan CM. Evidence-Based Use of Levothyroxine/Liothyronine Combinations in Treating Hypothyroidism: A Consensus Document. Eur Thyroid J 2021; 10:10-38. [PMID: 33777817 PMCID: PMC7983670 DOI: 10.1159/000512970] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 11/11/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Fourteen clinical trials have not shown a consistent benefit of combination therapy with levothyroxine (LT4) and liothyronine (LT3). Despite the publication of these trials, combination therapy is widely used and patients reporting benefit continue to generate patient and physician interest in this area. Recent scientific developments may provide insight into this inconsistency and guide future studies. METHODS The American Thyroid Association (ATA), British Thyroid Association (BTA), and European Thyroid Association (ETA) held a joint conference on November 3, 2019 (live-streamed between Chicago and London) to review new basic science and clinical evidence regarding combination therapy with presentations and input from 12 content experts. After the presentations, the material was synthesized and used to develop Summary Statements of the current state of knowledge. After review and revision of the material and Summary Statements, there was agreement that there was equipoise for a new clinical trial of combination therapy. Consensus Statements encapsulating the implications of the material discussed with respect to the design of future clinical trials of LT4/LT3 combination therapy were generated. Authors voted upon the Consensus Statements. Iterative changes were made in several rounds of voting and after comments from ATA/BTA/ETA members. RESULTS Of 34 Consensus Statements available for voting, 28 received at least 75% agreement, with 13 receiving 100% agreement. Those with 100% agreement included studies being powered to study the effect of deiodinase and thyroid hormone transporter polymorphisms on study outcomes, inclusion of patients dissatisfied with their current therapy and requiring at least 1.2 µg/kg of LT4 daily, use of twice daily LT3 or preferably a slow-release preparation if available, use of patient-reported outcomes as a primary outcome (measured by a tool with both relevant content validity and responsiveness) and patient preference as a secondary outcome, and utilization of a randomized placebo-controlled adequately powered double-blinded parallel design. The remaining statements are presented as potential additional considerations. DISCUSSION This article summarizes the areas discussed and presents Consensus Statements to guide development of future clinical trials of LT4/LT3 combination therapy. The results of such redesigned trials are expected to be of benefit to patients and of value to inform future thyroid hormone replacement clinical practice guidelines treatment recommendations.
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Affiliation(s)
- Jacqueline Jonklaas
- Division of Endocrinology, Georgetown University, Washington, District of Columbia, USA
- *Jacqueline Jonklaas, Division of Endocrinology, Georgetown University, 4000 Reservoir Road, NW, Washington, DC 20007 (USA),
| | - Antonio C. Bianco
- Section of Adult and Pediatric Endocrinology and Metabolism, University of Chicago, Chicago, Illinois, USA
| | - Anne R. Cappola
- Division of Endocrinology, Diabetes, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Francesco S. Celi
- Division of Endocrinology, Diabetes and Metabolism, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Eric Fliers
- Department of Endocrinology and Metabolism, Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Heike Heuer
- Department of Endocrinology, Diabetes and Metabolism, University Duisburg-Essen, Essen, Germany
| | | | - Lars C. Moeller
- Department of Endocrinology, Diabetes and Metabolism, University Duisburg-Essen, Essen, Germany
| | - Birte Nygaard
- Center for Endocrinology and Metabolism, Department of Internal Medicine, Herlev and Gentofte Hospitals, Herlev, Denmark
| | - Anna M. Sawka
- Division of Endocrinology, University Health Network and University of Toronto, Toronto, Ontario, Canada
| | - Torquil Watt
- Department of Endocrinology, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Colin M. Dayan
- Thyroid Research Group, School of Medicine, Cardiff University, Cardiff, United Kingdom
- **Colin M. Dayan, Thyroid Research Group, School of Medicine, Cardiff University, C2 Link, Heath Park, Cardiff CF14 4XN (UK),
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16
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Jonklaas J, Bianco AC, Cappola AR, Celi FS, Fliers E, Heuer H, McAninch EA, Moeller LC, Nygaard B, Sawka AM, Watt T, Dayan CM. Evidence-Based Use of Levothyroxine/Liothyronine Combinations in Treating Hypothyroidism: A Consensus Document. Thyroid 2021; 31:156-182. [PMID: 33276704 PMCID: PMC8035928 DOI: 10.1089/thy.2020.0720] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Background: Fourteen clinical trials have not shown a consistent benefit of combination therapy with levothyroxine (LT4) and liothyronine (LT3). Despite the publication of these trials, combination therapy is widely used and patients reporting benefit continue to generate patient and physician interest in this area. Recent scientific developments may provide insight into this inconsistency and guide future studies. Methods: The American Thyroid Association (ATA), British Thyroid Association (BTA), and European Thyroid Association (ETA) held a joint conference on November 3, 2019 (live-streamed between Chicago and London) to review new basic science and clinical evidence regarding combination therapy with presentations and input from 12 content experts. After the presentations, the material was synthesized and used to develop Summary Statements of the current state of knowledge. After review and revision of the material and Summary Statements, there was agreement that there was equipoise for a new clinical trial of combination therapy. Consensus Statements encapsulating the implications of the material discussed with respect to the design of future clinical trials of LT4/LT3 combination therapy were generated. Authors voted upon the Consensus Statements. Iterative changes were made in several rounds of voting and after comments from ATA/BTA/ETA members. Results: Of 34 Consensus Statements available for voting, 28 received at least 75% agreement, with 13 receiving 100% agreement. Those with 100% agreement included studies being powered to study the effect of deiodinase and thyroid hormone transporter polymorphisms on study outcomes, inclusion of patients dissatisfied with their current therapy and requiring at least 1.2 μg/kg of LT4 daily, use of twice daily LT3 or preferably a slow-release preparation if available, use of patient-reported outcomes as a primary outcome (measured by a tool with both relevant content validity and responsiveness) and patient preference as a secondary outcome, and utilization of a randomized placebo-controlled adequately powered double-blinded parallel design. The remaining statements are presented as potential additional considerations. Discussion: This article summarizes the areas discussed and presents Consensus Statements to guide development of future clinical trials of LT4/LT3 combination therapy. The results of such redesigned trials are expected to be of benefit to patients and of value to inform future thyroid hormone replacement clinical practice guidelines treatment recommendations.
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Affiliation(s)
- Jacqueline Jonklaas
- Division of Endocrinology, Georgetown University, Washington, District of Columbia, USA
- Address correspondence to: Jacqueline Jonklaas, MD, PhD, Division of Endocrinology, Georgetown University, 4000 Reservoir Road, NW, Washington, DC 20007, USA
| | - Antonio C. Bianco
- Section of Adult and Pediatric Endocrinology and Metabolism, University of Chicago, Chicago, Illinois, USA
| | - Anne R. Cappola
- Division of Endocrinology, Diabetes, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Francesco S. Celi
- Division of Endocrinology, Diabetes and Metabolism, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Eric Fliers
- Department of Endocrinology and Metabolism, Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam University Medical Center, Netherlands
| | - Heike Heuer
- Department of Endocrinology, Diabetes and Metabolism, University Duisburg-Essen, Essen, Germany
| | | | - Lars C. Moeller
- Department of Endocrinology, Diabetes and Metabolism, University Duisburg-Essen, Essen, Germany
| | - Birte Nygaard
- Center for Endocrinology and Metabolism, Department Internal Medicine, Herlev and Gentofte Hospitals, Herlev, Denmark
| | - Anna M. Sawka
- Division of Endocrinology, University Health Network and University of Toronto, Toronto, Canada
| | - Torquil Watt
- Department of Endocrinology, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Colin M. Dayan
- Thyroid Research Group, School of Medicine, Cardiff University, Cardiff, United Kingdom
- Address correspondence to: Colin M. Dayan, MD, PhD, Thyroid Research Group, School of Medicine, Cardiff University, C2 Link, Heath Park, Cardiff CF14 4XN, UK
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Planck T, Lantz M, Perros P, Papini E, Attanasio R, Nagy EV, Hegedüs L. Use of Thyroid Hormones in Hypothyroid and Euthyroid Patients: A 2020 THESIS Questionnaire Survey of Members of the Swedish Endocrine Society. Front Endocrinol (Lausanne) 2021; 12:795111. [PMID: 34938274 PMCID: PMC8687360 DOI: 10.3389/fendo.2021.795111] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 11/15/2021] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND The standard treatment of hypothyroidism is levothyroxine (LT-4). However, there are several controversies regarding treatment of hypothyroid patients. AIM To investigate the Swedish endocrinologists' use of thyroid hormones in hypothyroid and euthyroid individuals. METHODS Physician members of the Swedish Endocrine Society (SEF) were invited by e-mail to participate in an online survey investigating this topic. RESULTS Out of the eligible 411 members, 116 (28.2%) responded. The majority (98.9%) stated that L-T4 is the treatment of choice. However, around 50% also prescribed liothyronine (L-T3) or a combination of L-T4+L-T3 in their practice. Combination therapy was mostly (78.5%) used in patients with persistent hypothyroid symptoms despite biochemical euthyroidism on L-T4 treatment. Most respondents prescribed L-T4 tablets and did not expect any major changes with alternative formulations such as soft-gel capsules or liquid formulations in situations influencing the bioavailability of L-T4. In euthyroid patients, 49.5% replied that treatment with thyroid hormones was never indicated, while 47.3% would consider L-T4 for euthyroid infertile women with high thyroid peroxidase (TPO) antibody levels. CONCLUSION The treatment of choice for hypothyroidism in Sweden is L-T4 tablets. Combination therapy with L-T4+L-T3 tablets was considered for patients with persistent symptoms despite biochemical euthyroidism. Soft-gel capsules and liquid solutions of L-T4 were infrequently prescribed. Swedish endocrinologists' deviation from endocrine society guidelines merits further study.
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Affiliation(s)
- Tereza Planck
- Department of Endocrinology, Skåne University Hospital, Malmö, Sweden
- Department of Clinical Sciences Malmö, Lund University, Lund, Sweden
- *Correspondence: Tereza Planck,
| | - Mikael Lantz
- Department of Endocrinology, Skåne University Hospital, Malmö, Sweden
- Department of Clinical Sciences Malmö, Lund University, Lund, Sweden
| | - Petros Perros
- Department of Endocrinology, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom
| | - Enrico Papini
- Department of Endocrinology and Metabolism, Regina Apostolorum Hospital, Rome, Italy
| | - Roberto Attanasio
- Endocrine Unit, Institutes for Care and Scientific Research (IRCCS) Orthopedic Institute Galeazzi, Milan, Italy
| | - Endre V. Nagy
- Division of Endocrinology, Department of Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Laszlo Hegedüs
- Department of Endocrinology and Metabolism, Odense University Hospital, Odense, Denmark
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Razvi S, Mrabeti S, Luster M. Managing symptoms in hypothyroid patients on adequate levothyroxine: a narrative review. Endocr Connect 2020; 9:R241-R250. [PMID: 33112818 PMCID: PMC7774765 DOI: 10.1530/ec-20-0205] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 10/05/2020] [Indexed: 12/20/2022]
Abstract
The current standard of care for hypothyroidism is levothyroxine (LT4) monotherapy to reduce levels of thyrotropin (thyroid-stimulating hormone, TSH) within its reference range and amelioration of any symptoms. A substantial minority continues to report hypothyroid-like symptoms despite optimized TSH, however. These symptoms are not specific to thyroid dysfunction and are frequent among the euthyroid population, creating a therapeutic dilemma for the treating clinician as well as the patient. We present a concise, narrative review of the clinical research and evidence-based guidance on the management of this challenging population. The clinician may endeavor to ensure that the serum TSH is within the target range. However, the symptomatic patient may turn to alternative non-evidence-based therapies in the hope of obtaining relief. Accordingly, it is important for the clinician to check for conditions unrelated to the thyroid that could account for the ongoing symptoms such as other autoimmune conditions, anemia or mental health disorders. Systematic and thorough investigation of the potential causes of persistent symptoms while receiving LT4 therapy will resolve the problem for most patients. There may be some patients that may benefit from additional treatment with liothyronine (LT3), although it is unclear as yet as to which patient group may benefit the most from combined LT4 + LT3 therapy. In the future, personalized treatment with LT4 + LT3 may be of benefit for some patients with persistent symptoms of hypothyroidism such as those with polymorphisms in the deiodinase enzyme 2 (DIO2). For now, this remains a subject for research.
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Affiliation(s)
- Salman Razvi
- Translational and Clinical Research Institute, University of Newcastle, Newcastle-upon-Tyne, UK
- Correspondence should be addressed to S Razvi:
| | - Sanaa Mrabeti
- Medical Affairs EMEA, Merck Serono Middle East FZ-LLC, Dubai, United Arab Emirates
| | - Markus Luster
- Department of Nuclear Medicine, University Hospital Marburg, Marburg, Germany
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19
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Abstract
Background: The basis for the treatment of hypothyroidism with levothyroxine (LT4) is that humans activate T4 to triiodothyronine (T3). Thus, while normalizing serum thyrotropin (TSH), LT4 doses should also restore the body's reservoir of T3. However, there is evidence that T3 is not fully restored in LT4-treated patients. Summary: For patients who remain symptomatic on LT4 therapy, clinical guidelines recommend, on a trial basis, therapy with LT4+LT3. Reducing the LT4 dose by 25 mcg/day and adding 2.5-7.5 mcg liothyronine (LT3) once or twice a day is an appropriate starting point. Transient episodes of hypertriiodothyroninemia with these doses of LT4 and LT3 are unlikely to go above the reference range and have not been associated with adverse drug reactions. Trials following almost a 1000 patients for almost 1 year indicate that similar to LT4, therapy with LT4+LT3 can restore euthyroidism while maintaining a normal serum TSH. An observational study of 400 patients with a mean follow-up of ∼9 years did not indicate increased mortality or morbidity risk due to cardiovascular disease, atrial fibrillation, or fractures after adjusting for age when compared with patients taking only LT4. Desiccated thyroid extract (DTE) is a form of combination therapy in which the LT4/LT3 ratio is ∼4:1; the mean daily dose of DTE needed to normalize serum TSH contains ∼11 mcg T3, but some patients may require higher doses. The DTE remains outside formal FDA oversight, and consistency of T4 and T3 contents is monitored by the manufacturers only. Conclusions: Newly diagnosed hypothyroid patients should be treated with LT4. A trial of combination therapy with LT4+LT3 can be considered for those patients who have unambiguously not benefited from LT4.
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Affiliation(s)
- Thaer Idrees
- Section of Adult and Pediatric Endocrinology, Diabetes and Metabolism, University of Chicago, Chicago, Illinois, USA
| | - Scott Palmer
- Department of Medicine, Rush University Medical Center, Chicago, Illinois, USA
| | - Rui M.B. Maciel
- Division of Endocrinology, Universidade Federal de Sao Paulo, Sao Paulo, Brazil
| | - Antonio C. Bianco
- Section of Adult and Pediatric Endocrinology, Diabetes and Metabolism, University of Chicago, Chicago, Illinois, USA
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