Adherence to thyroid hormone replacement therapy: a retrospective, claims database analysis

Effect of Ramadan fasting on thyroid functions in hypothyroid patients taking levothyroxine: a systematic review and meta-analysis

BACKGROUND

The major changes in the timing of meals during Ramadan may be challenging for hypothyroid patients on levothyroxine. We aimed to study the effect of Ramadan fasting on thyroid functions in hypothyroid patients taking levothyroxine.

METHODS

We did a comprehensive search of 8 databases for Randomized controlled studies (RCTs) and observational studies investigating the effect of Ramadan fasting on thyroid functions in hypothyroid individuals taking levothyroxine. Relevant data was extracted and analyzed. Mean difference (MD) and standard deviation (SD) were used to evaluate the continuous data. Risk ratios (RR) with a 95% confidence interval were used for outcomes constituting dichotomous data. National Institutes of Health (NIH) tools were used to assess the risk of bias.

RESULTS

Fourteen studies met our inclusion criteria, 3 RCTs, and 11 observational studies, all designed as pre-post studies. Ramadan fasting was associated with a statistically significant increase in TSH in patients who were euthyroid before Ramadan (MD = -0.76 [95% CI; -1.27, -0.25]). However, free thyroxine (FT4) was found to be stable (MD = 0.01, [95% CI; -0.03, 0.06]). All timing points were associated with a significant increase in TSH levels after Ramadan, pre-iftar (MD = -0.69 [95% CI; -1.03, -0.36]), post-iftar (MD = -0.76 [95% CI; -1.12, -0.39]), and pre-suhoor (MD = -1.19 [95% CI; -2.18, -0.19]).

CONCLUSION

TSH increases significantly after Ramadan. No timing point has superiority in maintaining thyroid control. However, choosing the timing should be individualized according to the patient's preference to guarantee the most possible compliance.

Adherence of patients with schizophrenia to hypothyroidism treatment

Adherence to prescription medications is critical for both remission from schizophrenia and control of physical comorbidities. While schizophrenia with comorbid hypothyroidism is common, there is little research on adherence to hypothyroidism treatment in this population. The current study used a retrospective, matched case-control design. The cohort included 1,252 patients diagnosed with schizophrenia according to ICD-10 and 3,756 controls matched for gender, age, socioeconomic status and ethnicity without diagnosis of schizophrenia. All data were retrieved from the electronic medical database of a large health maintenance organization. Retrieved data included demographics, thyroid functionality test results and prescribed medications. Measures of adherence to therapy were used for analyses as were data from follow-ups of patients with hypothyroidism. A diagnosis of hypothyroidism was found in 299 patients, 115 of whom were also diagnosed with schizophrenia. The 184 without schizophrenia constituted the control group. No statistically significant differences were found between the two groups regarding prescriptions for L-thyroxin and TSH levels and number of TSH tests. Adherence of patients with schizophrenia to hypothyroidism treatment was found to be as good as that of individuals without a schizophrenia diagnosis.

Refractory Hypothyroidism: Unraveling the Complexities of Diagnosis and Management

INTRODUCTION

Refractory hypothyroidism (RH) represents a challenge in the diagnosis and treatment within the field of thyroidology. It is defined as the inability to achieve disease control despite using levothyroxine (LT4) doses of 1.9 μg/kg/d or higher.

METHODS

A comprehensive review, encompassing 103 articles, was conducted using the Scielo, Scopus, and EMBASE databases, providing an approach to evaluation and diagnosis of this condition.

RESULTS

LT4 disintegrates and dissolves within an acidic gastric environment before being absorbed in the jejunum and ileum. It then extensively binds to serum transporter proteins and undergoes deiodination to yield tri-iodothyronine, the biologically active hormone. There are various nonpathological causes of RH, such as noncompliance with treatment, changes in the brand of LT4, food and drug interferences, as well as pregnancy. Pathological causes include lactose intolerance, Helicobacter pylori infection, giardiasis, among others. The diagnosis of RH involves conducting a thorough medical history and requesting relevant laboratory tests to rule out causes of treatment resistance. The LT4 absorption test allows for the identification of cases of malabsorption. The treatment of RH involves identifying and addressing the underlying causes of noncompliance or malabsorption. In cases of pseudomalabsorption, supervised and weekly administration of LT4 may be considered.

DISCUSSION

Early recognition of RH and correction of its underlying cause are of utmost importance, as this avoids the use of excessive doses of LT4 and prevents cardiovascular and bone complications associated with this condition.

Adherence to levothyroxine treatment among patients with hypothyroidism in Oman: a national cross-sectional study

OBJECTIVE

Hormone replacement therapy with levothyroxine is considered the treatment of choice for hypothyroidism; however, non-adherence is a major contributor to poor treatment outcomes. This study aimed to evaluate levels of drug adherence (DA) to levothyroxine therapy among Omani adults with hypothyroidism and to explore related sociodemographic and clinical factors.

METHODS

A national, multi-center, cross-sectional survey was carried out from August to December 2021 at 18 primary healthcare centers across all governorates of Oman. A total of 415 Omani adults were recruited. Data were collected using a pre-tested, Arabic-language questionnaire completed by trained researchers during face-to-face interviews with the participants. Level of DA was determined using the 8-item Morisky Medication Adherence Scale (MMAS-8).

RESULTS

A total of 400 Omani adults participated in the study (response rate: 96.4%). The mean age was 41.9 ± 12.4 years old (range: 18-78 years) and 90.3% were female. According to their MMAS-8 scores, 157 (39.2%), 139 (34.8%), and 104 (26.0%) participants demonstrated low, medium, and high DA, respectively. No significant correlations were observed between level of DA and any sociodemographic or clinical characteristics, including age, gender, education, duration of treatment, and family history of thyroid disease (p > 0.050).

CONCLUSIONS

Only a quarter of Omani patients with hypothyroidism reported high levels of adherence to levothyroxine treatment, likely as a result of lack of awareness of the disease and the importance of maintaining an euthyroid state. Further studies using more objective measures of DA are recommended to determine correlates of non-compliance to levothyroxine therapy among Omani patients.

Abnormal TSH Prior to Surgery in Children with Graves' Disease Predicts Abnormal TSH Following Thyroidectomy

OBJECTIVE

To identify variables that are associated with poor compliance to thyroid hormone replacement therapy in children after total thyroidectomy.

METHOD

A retrospective cohort study of children who underwent total thyroidectomy by high-volume pediatric otolaryngologists between 1/2014 and 9/2021. Postoperative poor compliance was characterized by at least three separate measurements of high TSH levels not associated with radioactive iodine treatment.

RESULTS

There were 100 patients, ages 3-20 years old who met inclusion criteria; 44 patients underwent thyroidectomy for cancer diagnosis, and 56 for Graves' disease. The mean follow-up time was 36.5 months (range 3.0-95.6 months). Overall, 42 patients (42%) were found to have at least three measurements of high TSH during follow-up, and 29 patients (29%) were diagnosed with clinical hypothyroidism. Sex, race, income, insurance type, and benign versus malignant etiology for thyroidectomy were not associated with adherence to therapy. Multivariate regression analysis identified patients with Graves' disease and hyperthyroidism at the time of surgery and Hispanic ethnicity to be associated with postoperative clinical hypothyroidism (OR 9.38, 95% CI 2.16-49.2, p = 0.004 and OR 6.15, 95% CI 1.21-36.0, p = 0.033, respectively).

CONCLUSIONS

Preoperative hyperthyroidism in patients with Graves' disease and Hispanic ethnicity were predictors of postoperative TSH abnormalities. Preoperative counseling for patients and their families on the implications of total thyroidectomy and the need for life-long medications postoperatively is necessary. Efforts should be made to evaluate and improve adherence to therapy pre-and postoperatively in patients with Graves' disease.

LEVEL OF EVIDENCE

4 Laryngoscope, 133:2402-2406, 2023.

Investigating Levothyroxine Use and Its Association with Thyroid Health in Patients with Hypothyroidism: A Community Pharmacy Study

Background: To gain maximum therapeutic effect while minimizing side effects, it is imperative for patients with hypothyroidism to use their levothyroxine (LT4) correctly, such as adhering to the prescribed regimen. Little is currently known about how patients actually use LT4 in real life. We investigated the use of LT4, as well as the thyroid health (thyrotropin [TSH] and health-related quality of life [HR-QoL]), and evaluated if proper LT4 use is associated with better thyroid health. Methods: A cross-sectional observational study was conducted in a Belgian community sample of adults using LT4 for hypothyroidism since ≥2 years. Participants completed a self-administered questionnaire on patient characteristics, self-reported adherence to LT4, timing of intake, and co-medication. They also completed the thyroid-specific patient-reported outcome (ThyPRO-39) questionnaire, measuring the HR-QoL. Pharmacy dispensing data were used to calculate the medication possession ratio (MPR). Results: We included 856 participants (mean age 61.4 ± 14.3 years, 86% [740/856] females). Approximately one in four participants (138/563) had out-of-range TSH levels. Generally, ThyPRO-39 scores were in the lower part of the range (indicating better HR-QoL), with the scales "emotional susceptibility" and "tiredness" showing the worst scores. Approximately 28% (178/632) of the participants were classified as non-adherent (MPR <80%), corresponding to at least 73 cumulative days per year without LT4 intake. Twenty-five percent (212/854) of participants self-reported non-adherence, with unintentional non-adherence (forgetfulness) most frequently reported (21.9%, 187/854). Only 39% (329/836) of participants complied with the recommendation of ingesting LT4 ≥ 30 minutes before eating. Additionally, 7% (58/856) of participants concurrently used molecules that bind to LT4, without applying the recommended dosing interval. There was no significant correlation between LT4 usage (adherence, timing of intake, and interaction with complex forming drugs) and TSH or HR-QoL. Conclusions: We found that many participants with hypothyroidism did not use their LT4 as effectively as possible, particularly with respect to timing of administration. However, the participants' HR-QoL seemed largely satisfactory, and there was no significant correlation between correctly using LT4 and thyroid health.

Suboptimal adherence to food restrictions requirements related to drug regimens for chronic diseases

BACKGROUND

Oral medications for chronic conditions often involve a variety of instructions, including time of day/dosing, drug interactions, and food intake restrictions. However, the extent to which patients follow these instructions is unclear.

METHODS

We surveyed patients from the US and Europe (UK, France, Germany, Italy, Spain) who were prescribed sulfonylureas (SU: glimepiride, glipizide, or gliclazide) for diabetes or levothyroxine for hypothyroidism. Patients kept a daily diary for 3-5 days documenting their adherence to three criteria: dosing regimen including time of day, warning labels including drug interactions, and food restrictions.

RESULTS

A total of 421 US and 493 European patients took the study medications; 546 patients took SU and 368 took levothyroxine. Overall, 48% of patients were males; 46% were age 65 years or older. Despite most patients having received instructions on medication requirements (US 71%, EU 75%), most patients reported being only somewhat knowledgeable (US 69%; EU 71%). Adherence, measured by the proportion of the days a participant was adherent to each category out of the observational period (ranging from 3-5 days), varied by type of instruction, with the poorest adherence observed for food restriction requirements (US 34% of the observation days, EU 26%) compared to warning labels (US 77%, EU 67%) and dosing regimen (US 85%, EU 87%).

CONCLUSIONS

Patients adhered to dosing and cautionary instructions across the majority of the study period but were largely non-adherent to food intake restrictions. Improved communication and increased emphasis on food intake restrictions is needed when advising patients on their medications.

Comparative Bioavailability of a Novel Solution and a Tablet Formulation of Levothyroxine

Levothyroxine (LT4) is the standard of care for treating hypothyroidism. Despite the established efficacy of LT4, 50% of treated patients fail to achieve normal thyrotropin levels. Oral formulations of LT4 that bypass the gastric phase of dissolution may offset some of the therapeutic shortcomings observed with tablets. An oral solution of LT4 can be administered to patients who are unable to swallow tablets; allows flexibility to individualize dosing; and may mitigate interference with LT4 absorption caused by food, coffee, increased gastric pH from atrophic gastritis, and malabsorption from bariatric surgery. The bioavailability of a novel LT4 oral solution and a reference LT4 tablet were compared in a randomized, laboratory-blinded, single-dose, 2-period, 2-sequence, crossover study in healthy euthyroid subjects. A single 600-μg oral dose of LT4 solution (30 mL × 100 μg/5 mL) or tablet (2 × 300-μg tablet) was administered under fasting conditions in each study period, and total thyroxine concentrations were measured for 72 hours after administration. The ratio of geometric least-squares means and 90% confidence intervals for area under the concentration-time curve from time 0 to 72 hours and maximum plasma concentration were calculated. Among 42 subjects in the pharmacokinetic population, the geometric least-squares mean ratio of area under the concentration-time curve from time 0 to 72 hours and maximum plasma concentration for baseline-adjusted thyroxine was 109.1% and 107.9%, respectively, meeting Food and Drug Administration bioequivalence criteria. Adverse events (AEs) were similar between treatment groups with no serious AEs or discontinuations for AEs. Comparable bioavailability was observed between the LT4 oral solution and reference tablet after a single oral 600-μg dose under fasting conditions.

Impact of fasting on thyrotropin and thyroid status during Ramadan in 292 previously well controlled hypothyroid patients. IFTAR study

PURPOSE

Fasting during Ramadan affects thyrotropin both in healthy subjects and hypothyroid patients on adequate levothyroxine replacement. Few studies have addressed this effect in hypothyroid patients with pre-Ramadan euthyroidism. This study aims to report the impact of fasting in a relatively large cohort.

METHODS

This was a prospective study including hypothyroid patients who fasted Ramadan during the years 2018, 2019, and 2020 in Alexandria, Egypt. All patients were euthyroid. Patients chosen one of three levothyroxine regimens during Ramadan, regimen 1: 60 min before Iftar, regimen 2: 3-4 h after Iftar, 60 min before Suhor, regimen 3: before the start of next fast, 3-4 h after an early Suhor. Thyroid status was assessed in pre-Ramadan visit and reassessed in post-Ramadan visit within 6 weeks from the end of Ramadan.

RESULTS

The study included 292 hypothyroid patients. Most patients were adherent, 249 patients (85.3%), one sixth of patients were non-adherent, 43 patients (14.7%). Post-Ramadan TSH was 2.13 ± 1.88 mIU/L versus 1.60 ± 0.96 mIU/L pre-Ramadan [P = 0.001]. Most patients were still euthyroid post-Ramadan, 233 patients (79.8%), while 59 patients (20.2%) were dysthyroid. Post-Ramadan TSH significantly correlated to pre-Ramadan TSH [P < 0.001]. Post-Ramadan TSH was significantly higher in non-adherent patients, 3.57 ± 3.11 mIU/L compared to adherent patients, 1.88 ± 1.44 mIU/L [P < 0.001].

CONCLUSION

Fasting Ramadan in well controlled hypothyroid patients resulted in a significant increase in post-Ramadan TSH, yet 80% the patients remain euthyroid after Ramadan. Post-Ramadan TSH and euthyroidism are related to adherence and pre-Ramadan TSH.

Levothyroxine Absorption Test - Results and Follow Up of Patients from a Single Center

Introduction

Treating primary hypothyroidism with appropriate weight-based dosing is usually straightforward. When supraphysiologic doses of thyroxine are required, it is important to know the reason behind the increased requirement. When compliance with medication is assured and when there are no drug interactions resulting in increased thyroxine requirements, a levothyroxine absorption test (LT4AT) could be performed to diagnose the coexistence of malabsorption.

Materials and Methods

This was a single-center, retrospective chart review. Patients who had undergone LT4AT between 2018 and 2020 with a complete evaluation and follow-up records were reviewed. LT4AT and further evaluation (if necessary) were standardized, and details until the last review were obtained.

Results

In all, 11 patients had complete records and follow-up details. The median age (range) of the cohort was 24 years (19 to 46), and the duration of hypothyroidism was 8 years (4 to 24). Seven had low absorption (<60%) in LT4AT of which two each had celiac disease and Helicobacter pylori infection; one had autoimmune gastritis, and in two the reasons of malabsorption was not known. The median follow-up duration was 13 months. Nine of 11 (81%) achieved euthyroid state with/without thyroxine dose reduction on follow-up.

Conclusion

A high proportion of patients requiring supraphysiological doses of levothyroxine had occult malabsorptive states, some of which were curable. Even in those with pseudo-malabsorption, LT4AT helped in reinforcing compliance and thereby thyroxine dose reduction.

Long-Term Adherence to Levothyroxine Replacement Therapy in Thyroidectomized Patients

(1) Background: We evaluated the long term adherence to two distinct formulations of levothyroxine (L-T4), liquid or solid, which are differently influenced by concomitant food ingestion. (2) Methods: A total of 106 thyroidectomized patients (82 female, mean age 58.2 ± 13.3 years) on L-T4 replacement therapy in either liquid (n = 52) or solid formulation (n = 54) were administered the four-item Medication Adherence Questionnaire (MAQ). (3) Results: The study population had 59.4% adherers and 40.6% non-adherers. The global MAQ score was significantly better in patients under liquid L-T4 in comparison to those under solid L-T4 (0.42 ± 0.82 vs. 0.83 ± 0.95, respectively, p = 0.0085). The patients on tablet L-T4 forgot to take their medication more frequently than those on liquid LT4 treatment (p = 0.0159) and were more often careless at times about taking their medication (p = 0.007), whilst about one in two thyroidectomized patients preferred tablets for lifetime medication therapy. The global MAQ score was directly correlated with the circulating TSH levels in the whole study population (0.700, p < 0.0001) and inversely correlated with both the FT3 (−0.220, p = 0.0232) and FT4 (−0.327, p = 0.0006) serum concentrations. (4) Conclusions: Long-term adherence to L-T4 treatment was globally satisfactory although it was better for the liquid formulation, which appears to represent an easier-to-manage L-T4 replacement therapy for most thyroidectomized patients, particularly for those with difficulties in taking L-T4 while fasting.

Twice or Thrice Weekly versus Daily Thyroxine in Hypothyroid Fasting Ramadan: A Pilot Study

CONTEXT

Hypothyroid patients require to take levothyroxine (L-T4) on an empty stomach, 60 min before next meal which is difficult to achieve while fasting Ramadan, on a daily basis. This pilot study aimed to assess the effect of twice or thrice weekly versus standard daily L-T4 dosing during Ramadan on adherence, post-Ramadan TSH, and thyroid status.

METHODS AND MATERIALS

The study included 2 groups; group 1 included 11 patients assigned to take L-T4 twice or thrice a week, and group 2 included 113 patients assigned to take L-T4 daily. Patients chose between three L-T4 regimens: regimen 1 - 60 min before Iftar; regimen 2 - 60 min before Suhor, on empty stomach for 3-4 h; regimen 3 - before the next fast, on empty stomach for 3-4 h. Thyroid status was assessed before and within 6 weeks after Ramadan. Only euthyroid patients were included.

RESULTS

No significant differences between the two groups regarding adherence, post-Ramadan TSH, or post-Ramadan thyroid status. 90.9% in group 1 and 88.5% in group 2 were adherent [p = 1.000]. Post-Ramadan TSH in group 1 was 1.9 ± 1.5 mIU/L, in group 2 was 2 ± 1.6 mIU/L [p = 0.809]. 81.8% in group 1 and 82.3% in group 2 were euthyroid post-Ramadan [p = 0.209].

CONCLUSIONS

In this pilot study, taking L-T4 twice or thrice weekly during Ramadan achieved similar adherence and metabolic control to standard daily L-T4, making it an easier option for hypothyroid patients wishing to fast Ramadan.

Comparative Effectiveness of Persistent Use of a Name-Brand Levothyroxine (Synthroid®) vs. Persistent Use of Generic Levothyroxine on TSH Goal Achievement: A Retrospective Study Among Patients with Hypothyroidism in a Managed Care Setting

Introduction

Levothyroxine monotherapy (Synthroid® or multiple generic levothyroxine [GL] formulations) is standard treatment for hypothyroidism. Our objective was to compare effectiveness (as measured by achievement of thyroid-stimulating hormone [TSH] levels) and economic outcomes of Synthroid vs. any one of multiple GLs in patients with hypothyroidism.

Methods

Data for this retrospective cohort study were obtained from the HealthCore Integrated Research Database®. All study patients had ≥ 2 claims between 1 January 2006 and 31 December 2017 with ICD-9/10-CM diagnosis codes for hypothyroidism; were persistent users of Synthroid vs. any GL; and had ≥ 1 TSH laboratory result during 12-month follow-up. Patients were divided into one of two cohorts based on index medication and were 1:1 matched using propensity scores. The primary outcome was the proportion of patients with last TSH laboratory result during follow-up within the reference range (0.3–4.12 mIU/L). Secondary outcomes included all-cause and hypothyroidism-related healthcare resource utilization (HCRU) and costs.

Results

After propensity score matching, the Synthroid and GL cohorts each contained 18,382 patients. At follow-up, significantly more patients receiving Synthroid were in the TSH reference range vs. GL (78.5% vs. 77.2%, respectively, p =  0.002). HCRU and costs were broadly similar between the cohorts in terms of all-cause inpatient hospitalizations, emergency department visits, outpatient services, and pharmacy fills. Irrespective of index medication, patients with TSH within the reference range had significantly lower hypothyroidism-related medical and total costs compared to those outside the range.

Conclusions

This real-world data study showed Synthroid was associated with better TSH target achievement vs. GL in a US managed care population. Achieving TSH goals may provide substantial economic value by reducing hypothyroidism-related HCRU and costs.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-021-01969-3.

Real world evidence in effectiveness, safety, and cost savings of generic levothyroxine: a systematic review

PURPOSE

Generic levothyroxine, approved through Abbreviated New Drug Application (ANDA), is available for generic substitution. But ANDA does not require nonclinical or clinical data to establish safety and efficacy. Post-marketing evidence in generic equivalence for marketed levothyroxine products is limited. We conducted a systematic review to synthesize evidence in effectiveness, safety, and cost savings between patients using generic and branded levothyroxine.

METHODS

We systematically searched published literature from Medline, International Pharmaceutical Abstracts, APA PsycInfo, and CINAHL from inception through 04/18/2021. Included studies were limited to post-marketing empirical studies including patients who used levothyroxine products, with direct comparison between generic and brand levothyroxine, and published in English. Risk of bias was assessed using the National Institute of Health Study Quality Assessment Tools. Two reviewers independently extracted data and conducted quality assessment for included studies. Given that the nine studies are so diverse, a meta-analysis was not possible. Therefore we provided a narrative review of the included studies.

RESULTS

Of 349 studies identified, nine met the inclusion criteria. Six studies compared thyrotropin levels and adverse events between generic and brand users and provided mixed findings. In addition, generic users may generate prescription cost savings for payers but had suboptimal medication adherence than brand users.

CONCLUSION

Findings from this systematic review highlighted the limited and mixed evidence in real-world clinical and economic outcomes for generic levothyroxine. Continuous post-marketing monitoring and assessment of generic drugs are warranted to ensure treatment effectiveness, patient safety, and achieve financial savings in prescription costs.

The Relationship Between Brain Fog and Medication Adherence for Individuals With Hypothyroidism

Individuals with hypothyroidism suffer from symptoms including impairments to cognition (i.e., "brain fog"). Medication can help reduce symptoms of hypothyroidism; however, brain fog may hinder adherence. The aim of this study was to determine if memory impairment and cognitive failures are related to treatment nonadherence in 441 individuals with hypothyroidism. Participants with a diagnosis of hypothyroidism and currently prescribed a thyroid hormone replacement medication were placed in two groups according to adherence level and compared on validated scales assessing impairments to memory and cognition. Results indicated a significant association between treatment nonadherence and self-reported brain fog, represented by greater cognitive and memory impairments. Nonadherent individuals indicated impairments with prospective, retrospective, and short- and long-term memory; and more cognitive failures, compared to adherent individuals. Findings suggest the importance of interventions to enhance adherence for individuals with brain fog, such as encouraging the use of reminders.

Evaluation of adherence to levothyroxine and out-of-range thyroid-stimulating hormone levels in pregnant women with primary hypothyroidism

PURPOSE

Adherence to levothyroxine (LT4) and attaining thyroid-stimulating hormone (TSH) goal in pregnancy has not been well-defined yet. We aimed to investigate adherence to LT4, success to reach TSH goal, and association between them in pregnant women with primary hypothyroidism.

MATERIALS AND METHODS

Eight-item Morisky Medication Adherence Scale (MMAS-8) was applied in third trimester in pregnant women with primary hypothyroidism (Hashimoto's thyroiditis, surgical hypothyroidism or iodine deficiency) whom LT4 was given for at least 3 months. Those with chronic illness or thyroid cancer were excluded. We grouped the patients according to MMAS-8 score (<6, low adherence vs ≥6, medium/high adherence), and TSH measurement in third trimester (in-range vs out-of-range).

RESULTS

Of total (n = 85), 57.64% (n = 49) had medium/high adherence to LT4, and 41.17% (n = 35) out-of-range TSH, but no association was found among them (P = .937). LT4 initiation in pregestational period, surgical hypothyroidism, high LT4 dose in second/third trimester and alternate-day dosing were associated with medium/high adherence. Age, number of visits, and less time between ingestion of LT4 and breakfast were associated with medium/high adherence. LT4 dose in second trimester and dose increment at the beginning of pregnancy were positively associated with in-range TSH.

CONCLUSION

Non-adherence and treatment failure are frequent in LT4-treated pregnant women. Adherence seems not to be associated with treatment success. Regular follow-up may improve adherence. Our study is the first to analyse both treatment success and adherence to LT4 in pregnancy.

New Formulations of Levothyroxine in the Treatment of Hypothyroidism: Trick or Treat?

Background: Levothyroxine (LT4) as a medication is used by up to 5.3% of the adult population. For optimal efficacy, the traditional tablet formulation (LT4tab) requires that patients avoid concomitant ingestion with food, drinks, and certain medications, as well as excellent patient compliance. Some comorbidities influence bioavailability of LT4 and may mandate repeated dose adjustments. Summary: New LT4 formulations (soft gel [LT4soft] and liquid [LT4liq]) containing predissolved LT4 are claimed to improve bioavailability, presumably by facilitating absorption. Thus, these formulations may well be more suitable than LT4tab for patients whose daily requirements are subjected to variations in bioavailability. Here, we review the evidence and indications for use of new LT4 formulations and highlight areas of uncertainty that are worthy of further investigation. While bioequivalence is established for LT4soft and LT4liq administered to healthy volunteers compared with LT4tab in pharmacokinetic (PK) studies, therapeutic equivalence of the new formulations seems to be different in several clinical settings. Some evidence suggests that new formulations of LT4 may mitigate against the strict requirements relating to concomitant ingestion with food, drinks, and certain medications, which apply to traditional LT4 tablets. The principal indication is in selected patients with disease fluctuations and intermittent therapies with interfering medications, where the need for frequent dose adjustments and office visits may be diminished. Whether the use of LT4soft or LT4liq in patients with impaired gastric acid secretion results in better control of hypothyroidism than LT4tab remains unclear. Conclusions: The evidence in favor of using LT4soft and LT4liq in clinical practice over LT4tab is weak, and the underlying putative PK mechanisms unclear. Additional studies to investigate these potential benefits, define the cost-effectiveness, and understand the PK mechanisms involved with new LT4 formulations are needed.

The Association Between Switching from Synthroid® and Clinical Outcomes: US Evidence from a Retrospective Database Analysis

Introduction

Clinical guidelines recommend levothyroxine as the standard of care for hypothyroidism and that patients should be treated with a consistent preparation of synthetic levothyroxine without switching among formulations. This study examines the likelihoods of negative clinical outcomes between continuous users of Synthroid^® (AbbVie, Inc.) and patients who switch from Synthroid^® to an alternative formulation of levothyroxine.

Methods

This retrospective cohort analysis utilized data from Optum Clinformatics™ DataMart covering May 1, 2000 to March 30, 2016. After 6 months of consistent use of Synthroid^®, patients were categorized as continuous users or as switchers (by filling a prescription for an alternative formulation). Key outcomes included the likelihood of a thyroid-stimulating hormone (TSH) laboratory value out of a guideline recommended range and/or an adverse clinical composite endpoint identified by ICD codes in the patient’s claims data over the following 2 years for any of the following: chronic kidney disease, depression, fatigue, heart failure, hyperlipidemia, hypertension, or obesity. Individual components of the composite endpoint were also examined. Outcomes were analyzed using multivariable logistic models on propensity score matched cohorts. Analyses controlled for patient characteristics using SAS 9.4 software. Chi-square and t tests were employed and P < 0.05 was pre-specified as statistically significant.

Results

Propensity score matching resulted in a sample of 9925 continuous users and 9925 switchers. Switchers were significantly more likely than continuers to have a TSH laboratory value out-of-range in the post-period [odds ratio (OR) 1.15; 95% confidence interval (CI) (1.08–1.23)]. Switchers were also more likely to have the composite clinical endpoint [OR 1.23; CI (1.12–1.37)] and to have individual diagnoses of chronic kidney disease, depression, fatigue, hypertension, or obesity in the post-period.

Conclusions

Results of this large retrospective study over an extended time horizon support clinical guideline recommendations that switching among alternative formulations of synthetic levothyroxine should generally be avoided. Continuous use of Synthroid^® was associated with a significantly higher likelihood of maintaining the TSH laboratory value within a guideline recommended range and a significantly lower likelihood of being diagnosed with adverse clinical outcomes.

Managing symptoms in hypothyroid patients on adequate levothyroxine: a narrative review

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.

Levothyroxine Replacement in Obese Adults: The Role of Metabolic Variables and Aging on Thyroid Testing Abnormalities

CONTEXT

General rates of over- and underreplacement in levothyroxine (LT4) users with primary hypothyroidism are variably high. No information on LT4 adequacy exists in obesity.

OBJECTIVE

We explored rates and factors relating to LT4 adequacy in obese patients with primary hypothyroidism.

SETTING

Tertiary care center.

DESIGN

Among 4954 consecutive obese patients admitted between 2011 and 2014, 691 hypothyroid patients receiving LT4 therapy and 691 body mass index (BMI)-, age-, and sex-matched euthyroid controls underwent analysis of thyroid function, glucolipid profile, body composition, and indirect calorimetry. LT4 users were classified into low TSH (<0.27 mU/L), euthyroid (0.27 to 4.2 mU/L), and high TSH (>4.2 mU/L).

RESULTS

LT4 users constituted 13.9% of the incident population. TSH was low in 7.5%, high in 17.2%, and normal in 75.2% of LT4 users. Overtreatment decreased with aging and more LT4 users ≥65 years of age had normal TSH than those <65 years of age (P < 0.05). Compared with the euthyroid obese group, LT4 users showed higher adiposity, similar insulin resistance, but a healthier lipid profile. In multivariable analyses, LT4 dose was predicted by fat-free mass, hypothyroidism cause, and sex (P < 0.0001 to < 0.05). Risk of LT4 overreplacement increased with younger age (OR 0.96; 95% CI 0.94 to 0.99), higher LT4 dose (OR 2.98; 95% CI 1.44 to 6.14), and lower BMI (OR 0.93; 95% CI 0.88 to 0.99). Male sex increased the likelihood of LT4 underreplacement (OR 2.37; 95% CI 1.10 to 5.11).

CONCLUSIONS

Obesity is associated with milder rates of inadequate LT4 treatment compared with nonobese populations. LT4 adequacy increases with aging. Age, body composition, and sex are main determinants of LT4 requirements in obesity.

Adherence to Levothyroxine Treatment Among Patients With Hypothyroidism: A Northeastern Italian Survey

Background: A significant number of patients show sub-optimal adherence to levothyroxine (LT4) therapy, mainly because they have to postpone their breakfast by at least 30 min. The aim of this observational cross-sectional study was to assess the therapeutic compliance of patients on LT4 treatment and to verify the preference of a lifetime treatment in tablet or liquid form. Patients and Methods: Ambulatory care patients aged 18 years or older, affected by hypothyroidism and on LT4 treatment (in tablet or liquid form) were administered the eight-item Morisky Medication Adherence Scale (MMAS-8). The MMAS-8 questionnaire was supplemented with 3 further items to specifically evaluate preference between tablet and liquid forms of LT4 for lifetime treatment. Results: A total of 320 patients (272 female), median age 47.9 ± 15.6 years (range, 20-78 years), completed the MMAS-8 questionnaire. Eighty-seven percent of the participants were adhering to their treatment for both tablet and liquid LT4 formulations, although significant differences emerged. Patients on LT4 tablets forgot to take their medication more frequently (p < 0.001), felt hassled about sticking to their treatment plan (p < 0.001), and had difficulty remembering to take all their medication(s) (p < 0.001) than those on liquid LT4 treatment. Conclusions: Adherence to LT4 treatment was high for both tablet and liquid formulations. Taking LT4 at breakfast was the most convenient option for most patients.