Cost effectiveness of screening for subclinical hypothyroidism in the elderly. A decision-analytical model

Hypothyroidism in Adult Women: The Utility of Targeted vs Universal Thyroid Screening

Hypothyroidism is a common disease that is more prevalent in female populations. The purpose of this paper is to discuss the evidence, risks, and benefits of screening asymptomatic women for hypothyroidism. There is lack of evidence to support clinical management of asymptomatic individuals with an elevated TSH and normal serum thyroxine levels. Patients with subclinical hypothyroidism, especially the elderly, are at risk of overtreatment. Given these considerations, the majority of US and UK professional organizations do not support universal screening. Many do offer caveats for special groups, including pregnant people, who may need screening if there are clinical symptoms or family history of autoimmune disease. In conclusion, targeted screening may be best recommended based on risk factors, symptoms, and clinical suspicion, rather than at a universal level.

Decision-Analytic Modeling Studies in Prevention and Treatment of Iodine Deficiency and Thyroid Disorders: A Systematic Overview

Background: Prevention and treatment of iodine deficiency-related diseases remain an important public health challenge. Iodine deficiency can have severe health consequences, such as cretinism, goiter, or other thyroid disorders, and it has economic implications. Our aim was to give an overview of studies applying decision-analytic modeling to evaluate the effectiveness and/or cost-effectiveness of iodine deficiency-related prevention strategies or treatments related to thyroid disorders. Methods: We performed a systematic literature search in PubMed/MEDLINE (Medical Literature Analysis and Retrieval System Online), EMBASE (Excerpta Medica Database), Tuft's Cost-Effectiveness Analysis Registry, and National Health System Economic Evaluation Database (NHS EED) to identify studies published between 1985 and 2018 comparing different prevention or treatment strategies for iodine deficiency and thyroid disorders by applying a mathematical decision-analytic model. Studies were required to evaluate patient-relevant health outcomes (e.g., remaining life years, quality-adjusted life years [QALYs]). Results: Overall, we found 3950 studies. After removal of duplicates, abstract/title, and full-text screening, 17 studies were included. Eleven studies evaluated screening programs (mainly newborns and pregnant women), five studies focused on treatment approaches (Graves' disease, toxic thyroid adenoma), and one study was about primary prevention (consequences of iodine supplementation on offspring). Most of the studies were conducted within the U.S. health care context (n = 7). Seven studies were based on a Markov state-transition model, nine studies on a decision tree model, and in one study, an initial decision tree and a long-term Markov state-transition model were combined. The analytic time horizon ranged from 1 year to lifetime. QALYs were evaluated as health outcome measure in 15 of the included studies. In all studies, a cost-effectiveness analysis was performed. None of the models reported a formal model validation. In most cases, the authors of the modeling studies concluded that screening is potentially cost-effective or even cost-saving. The recommendations for treatment approaches were rather heterogeneous and depending on the specific research question, population, and setting. Conclusions: Overall, we predominantly identified decision-analytic modeling studies evaluating specific screening programs or treatment approaches; however, there was no model evaluating primary prevention programs on a population basis. Conclusions deriving from these studies, for example, that prevention is cost-saving, need to be carefully interpreted as they rely on many assumptions.

Reference intervals for thyroid-stimulating hormone, free thyroxine, and free triiodothyronine in elderly Chinese persons

Background Thyroid hormone levels are essential for diagnosing and monitoring thyroid diseases. However, their reference intervals (RIs) in elderly Chinese individuals remain unclear. We aimed to identify factors affecting thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) levels using clinical "big data" to establish hormone level RIs for elderly Chinese individuals. Methods We examined 6781, 6772, and 6524 subjects aged ≥65 years who underwent FT3, FT4, and TSH tests, respectively, at the Peking Union Medical College Hospital between September 1, 2013, and August 31, 2016. Hormones were measured using an automated immunoassay analyzer (ADVIA Centaur XP). RIs were established using the Clinical Laboratory Standards Institute document C28-A3 guidelines. Results The median TSH was significantly higher in women than in men; the opposite was true for median FT3 and FT4 levels. No differences were observed in TSH or FT4 by age in either sex or overall; FT3 levels significantly decreased with age. Seasonal differences were observed in TSH and FT3 levels but not FT4 levels; the median TSH was the highest in winter and lowest in summer, whereas the median FT3 was the lowest in summer (albeit not significantly). RIs for TSH were 0.53-5.24 and 0.335-5.73 mIU/L for men and women, respectively; those for FT3 were 3.76-5.71, 3.60-5.42, and 3.36-5.27 pmol/L in 64- to 74-, 75- to 84-, and 85- to 96-year-old subjects, respectively. The RI for FT4 was 11.70-20.28 pmol/L. Conclusions RIs for TSH in elderly individuals were sex specific, whereas those for FT3 were age specific.

Hypothyroidism during pregnancy: Controversy over screening and intervention

Thyroid hormones are critical for foetal neurological development and maternal health. Maternal hypothyroidism during pregnancy is associated with adverse impact on health of the mother as well as the progeny. Reduced thyroid hormone levels predispose the child to develop mental retardation and cognitive delay in early life. In the mother, hypothyroidism during pregnancy is associated with spontaneous abortion, placental abruption, preterm delivery and hypertensive disorders. Therefore, screening and therapeutic intervention is justified to prevent foetal as well as maternal co-morbidities. In view of impact of such a large-scale screening and intervention program on limited healthcare resources, it is debatable if a targeted rather than universal screening program will result in comparable outcomes. In addition, there is an ongoing debate regarding best evidence-based practice for the management of isolated hypothyroxinaemia, subclinical hypothyroidism and euthyroid women with autoimmune hypothyroidism. We have carried out a review of the literature; firstly, to determine whether universal screening for asymptomatic women in early pregnancy would be cost-effective. Secondly, we have retrospectively reviewed the literature to analyse the evidence regarding the impact of therapeutic intervention in women with subclinical hypothyroidism.

Investigating the Generalizability of Economic Evaluations Conducted in Italy: A Critical Review

OBJECTIVES

To assess the methodological quality of Italian health economic evaluations and their generalizability or transferability to different settings.

METHODS

A literature search was performed on the PubMed search engine to identify trial-based, nonexperimental prospective studies or model-based full economic evaluations carried out in Italy from 1995 to 2013. The studies were randomly assigned to four reviewers who applied a detailed checklist to assess the generalizability and quality of reporting. The review process followed a three-step blinded procedure. The reviewers who carried out the data extraction were blind as to the name of the author(s) of each study. Second, after the first review, articles were reassigned through a second blind randomization to a second reviewer. Finally, any disagreement between the first two reviewers was solved by a senior researcher.

RESULTS

One hundred fifty-one economic evaluations eventually met the inclusion criteria. Over time, we observed an increasing transparency in methods and a greater generalizability of results, along with a wider and more representative sample in trials and a larger adoption of transition-Markov models. However, often context-specific economic evaluations are carried out and not enough effort is made to ensure the transferability of their results to other contexts. In recent studies, cost-effectiveness analyses and the use of incremental cost-effectiveness ratio were preferred.

CONCLUSIONS

Despite a quite positive temporal trend, generalizability of results still appears as an unsolved question, even if some indication of improvement within Italian studies has been observed.

Hypothyroidism and subclinical hypothyroidism in the older patient

OBJECTIVE

To review the etiology, precipitating factors, clinical findings, screening recommendations, and treatment for primary hypothyroidism and subclinical hypothyroidism in the older patient.

DATA SOURCES

A PubMed search of English language articles using a combination of words: elderly, thyroid, hypothyroid,* subclinical hypothyroid,* etiology, screening, diagnosis, and treatment to identify original studies, guidelines, and reviews on primary hypothyroidism and subclinical hypothyroidism published between 1979 and present.

STUDY SELECTION AND DATA EXTRACTION

Overall, 51 clinical reviews, original studies, references, and guidelines were obtained and evaluated on their clinical relevance to the older patient population.

DATA SYNTHESIS

The literature included guidelines and considerations for the diagnosis, screening, and management of subclinical and overt primary hypothyroidism in the older patient.

CONCLUSION

Females and individuals 60 years of age or older have a higher prevalence of primary hypothyroidism and subclinical hypothyroidism. While screening recommendations exist, the need or suggested age to initiate screening varies among organizations. TSH and free T4 values are used for diagnosing and monitoring. Levothyroxine remains the drug of choice for replacing endogenous thyroid hormone. Despite evidence to suggest its need, the treatment of subclinical hypothyroidism remains controversial.

Abnormal thyroid stimulating hormone (TSH) in psychiatric long-term care patients

The objective of the study was to find the prevalence of thyroid dysfunction in long-term care patients referred to psychiatry. We reviewed 868 charts of long-term care residents referred for psychiatric consultation to the university-based psychiatry outreach service. Data obtained were demographics, psychiatric and thyroid diagnoses, and TSH data. Of 868 patients, 10.8% had elevated TSH, 8% in those with a prior diagnosis of hypothyroidism. TSH was low in 0.07%. Elevated TSH was associated with female gender (p<0.001) and a trend with psychosis (p=0.056). No association was found with depression or behavioral disturbance in this study.

Screening pregnant women for autoimmune thyroid disease: a cost-effectiveness analysis

OBJECTIVE

Untreated maternal hypothyroidism during pregnancy can have adverse consequences on maternal health and child intelligence quotient (IQ). Our objective was to examine the cost-effectiveness of screening pregnant women for autoimmune thyroid disease.

DESIGN

We developed a state-transition Markov model and performed a cost-effectiveness analysis of screening pregnant US women, aged 15-45 years, with no known history of thyroid disease, in the first trimester.

METHODS

Three strategies were compared: 1) no screening, 2) one-time screening using anti-thyroid peroxidase (anti-TPO) antibodies, and 3) one-time screening using TSH. Screening tests were added to the laboratory tests of the first prenatal visit. Abnormal screening tests were followed by further testing and subsequent thyroxine treatment of hypothyroid women.

RESULTS

Screening pregnant women in the first trimester using TSH was cost-saving compared with no screening. Screening using anti-TPO antibodies was cost-effective compared with TSH screening with an incremental cost-effectiveness ratio of $15,182 per quality-adjusted life year. Screening using TSH remained cost-saving across a wide range of ages at screening, costs of treatment, and probabilities of adverse outcomes. The cost-effectiveness of anti-TPO screening compared with TSH screening was mostly influenced by the probability of diagnosing hypothyroidism in unscreened subjects or subjects with a normal screening test. Screening remained highly cost-effective in scenarios where we assumed no improvement of child IQ outcomes by levothyroxine treatment.

CONCLUSION

Screening all pregnant women for autoimmune thyroid disease in the first trimester is cost-effective compared with not screening.

[Hashimoto's hypothyroidism associated with insulin resistance in type 2 diabetes]

INTRODUCTION Thyroid peroxidase activity inhibiting immunoglobulins (anti-TPO Ab) is a sign of autoimmune process in the thyroid gland. Association of hyperthyroidism and diabetes mellitus has been classically described. However, hypometabolic state, as a consequence of hypothyroidism, is not frequently linked with the biological activity of insulin. CASE DESCRIPTION A 51-year old man was admitted to the Clinic with unregulated diabetes, untreated for 5 yrs. Insulin therapy was introduced one year before, with 96 units on admission. He had bowel movements every three days. BH 176cm, BW 120kg, a puffy face and swollen body. Fundus examination did not show specific diabetic leasions. Hepatic steatosis was present on ultrasound examination. Occlusion of coronary arteries and superficial femoral artreries was present on angiography, and stenosis of carotid artreies on doppler duplex examination. HbA1c 14.7%. TSH 85.7 mlU/l, FT4 1.6 pmol/l, FT3 1.4. Anti TPO Ab >600 IU/ml, triglycerides 2.26 mmol/l, HDL 1.15, cholesterolemia 10.0. Levothyroxine substitution was introduced starting with 25 mgr, gradually increasing up to 75 mgr. The need for insulin gradually decreased and finally it was switched to glibenclamide 5mg +0+2.5 mg. On discharge his FBG was 7.0 mmol/l. HOMA -B 52.3, HOMA-R 9.8. DISCUSSION We can conclude that in our patient secondary obesity caused deterioration of diabetes. After introduction of substitution therapy with levothyroxine, decrease of insulin resistance and of cholesterol level was established. The duration of undiagnosed hypothyroidism can be a matter of speculation. However, the beneficial effect of normalized metabolism on atherosclerotic process will be obvious in the future.

Cost-effectiveness of proton radiation in the treatment of childhood medulloblastoma

BACKGROUND

Radiation therapy is an important component in the treatment of medulloblastoma; however, in many patients, it is associated with risk of late adverse events. Proton radiation therapy has potential to reduce the risk of adverse events compared with conventional radiation, but it is associated with a higher treatment cost. The objective of the current study was to assess the cost-effectiveness of proton therapy compared with conventional radiation therapy in the treatment of childhood medulloblastoma.

METHODS

The consequences of radiation therapy were evaluated using a Markov simulation model. Children age 5 years with medulloblastoma were followed. The patients were at risk of several types of adverse events, including hearing loss, intelligence quotient (IQ) loss, hypothyroidism, growth hormone deficiency (GHD), osteoporosis, cardiac disease, and secondary malignancies. The patients also were at risk of death and were divided into risk groups for normal death, death due to tumor recurrence, treatment-related cardiac death, treatment-related subsequent tumor death, or treatment-related other death. A review of the literature was conducted to estimate the parameters in the model.

RESULTS

The base-case results showed that proton therapy was associated with 23,600 in cost savings and 0.68 additional quality-adjusted life-years per patient. The analyses showed that reductions in IQ loss and GHD contributed to the greatest part of the cost savings and were the most important parameters for cost-effectiveness.

CONCLUSIONS

The results of the current study indicated that proton radiation therapy can be cost-effective and cost-saving compared with conventional radiation therapy in the treatment of children with medulloblastoma if the appropriate patients are selected for the therapy. However, there have been few long-term follow-up studies, and more much information on the long-term consequences of radiation therapy is needed.

Radioiodine or surgery for toxic thyroid adenoma: dissecting an important decision. A cost-effectiveness analysis

OBJECTIVE

To examine the cost effectiveness of therapeutic strategies for toxic thyroid adenoma.

DESIGN

Markov state transition decision analytic model.

SETTING

Ambulatory and inpatient.

PATIENTS

Hypothetical cohort of 40- year-old women with toxic thyroid adenomas. Patient age was varied in sensitivity analyses. Data on the prevalence of coincident thyroid cancer, complications, and treatment efficacies were derived from a systematic review of the literature.

INTERVENTIONS

Thyroid lobectomy after a 3 month-course of antithyroid drugs (ATDs), high-dose (<555 MBq) radioactive iodine (RAI), low-dose (>555 MBq) RAI, and lifelong ATDs.

MEASUREMENTS AND MAIN RESULTS

Outcomes were measured in quality-adjusted life years (QALYs). Costs were estimated from the health care system perspective. Future costs and effectiveness were discounted at 3% per year. For a 40- year-old woman, surgery was the most effective, while low-dose RAI was the least costly. The marginal cost-effectiveness of surgery versus low-dose RAI was $13,183 per QALY. Surgery was less costly and more effective than lifelong ATDs. RAI was more effective than surgery if surgical mortality exceeded 0.90% (base-case 0.001%). Surgery provided relatively inexpensive gains (<$50,000 per QALY) in quality-adjusted life expectancy in patients less than 74 years of age.

CONCLUSIONS

For most patients less than 60 years of age, surgery is an effective strategy with a reasonable cost. However, for any given patient, surgical mortality, therapeutic costs and preference must be considered in choosing an appropriate therapy.

Hypothyroidism

Hypothyroidism is common, potentially serious, often clinically overlooked, readily diagnosed by laboratory testing, and eminently treatable. The condition is particularly prevalent in older women, in whom autoimmune thyroiditis is common. Other important causes include congenital thyroid disorders, previous thyroid surgery and irradiation, drugs such as lithium carbonate and amiodarone, and pituitary and hypothalamic disorders. Worldwide, dietary iodine deficiency remains an important cause. Hypothyroidism can present with nonspecific constitutional and neuropsychiatric complaints, or with hypercholesterolaemia, hyponatraemia, hyperprolactinaemia, or hyperhomocysteinaemia. Severe untreated hypothyroidism can lead to heart failure, psychosis, and coma. Although these manifestations are neither specific nor sensitive, the diagnosis is confirmed or excluded by measurements of serum thyrotropin and free thyroxine. Thyroxine replacement therapy is highly effective and safe, but suboptimal dosing is common in clinical practice. Patient noncompliance, drug interactions, and pregnancy can lead to inadequate treatment. Iatrogenic thyrotoxicosis can cause symptoms, and, even when mild, provoke atrial fibrillation and osteoporosis. We summarise present understanding of the history, epidemiology, pathophysiology, and clinical diagnosis and management of hypothyroidism.

Thyroid disease

Evaluation and treatment of thyroid disease is a common feature of primary care medicine. Nevertheless, the dose of thyroid hormone used to treat hypothyroidism is frequently not titrated to normalize the TSH, engendering the risks of under- or overtreatment. Other hypothyroid patients remain symptomatic even with normalized TSH on levothyroxine alone. Some of these patients improve symptomatically when liothyronine is added to the treatment regimen. Subclinical hypothyroidism and hyperthyroidism are also relatively common in primary care medical practice, and appropriately selected patients probably benefit from treatment. In the follow-up of patients treated for thyroid cancer, the use of rhTSH improves patient comfort considerably while allowing sensitive screening for persistent or recurrent cancer.

[Subclinical thyroid disease in institutionalised healthy geriatric population]

BACKGROUND

Our aim was to determine the prevalence of subclinical thyroid disease in a healthy institutionalised geriatric population.

PATIENTS AND METHOD

We determined TSH, free T4 and antithyroid antibodies from 242 healthy elderly subjects living in Andalusian public nursing homes.

RESULTS

Subclinical hypothyroidism was detected in 3.71% of cases; clinical hypothyroidism in 1.65%; subclinical hyperthyroidism in 0.82%,and autoimmune disease in 10.33%.

CONCLUSIONS

There is a high rate of clinically undetected thyroid dysfunction among the healthy institutionalised geriatric population. Therefore, a hormonal screening may be justified in this population.

When to treat mild hypothyroidism

The availability and wide acceptance of TSH assays for primary assessment of thyroid function has led to the recognition that mild thyroid hormone deficiency is characterized by elevation of the serum TSH concentration despite a normal free thyroxine level. Other conditions can also cause isolated serum TSH elevation, and these conditions can be distinguished from mild thyroid failure usually based-on clinical and circumstantial observations alone. Thyroxine treatment of patients with mild hypothyroidism has been shown in most, but not all, clinical trials to lower atherogenic lipid levels and relieve certain somatic and neuropsychiatric symptoms. Such treatment also prevents the progression to overt hypothyroidism, which is particularly likely in patients who are older, who have circulating thyroid autoantibodies, or who have a serum TSH greater than 10 mU/L. After the optimal thyroxine dose has been defined, long-term monitoring of patients with an annual clinical evaluation and serum TSH measurement is appropriate. The high prevalence of mild hypothyroidism, particularly in older women, and its subtle clinical presentation have led some authorities to recommend a low threshold for case-finding or routine population screening for the disorder.

Prevalence of subclinical hypothyroidism in a population living in the Milan metropolitan area

Subclinical hypothyroidism is a condition characterized by increased levels of thyroid-stimulating hormone (TSH) associated with normal levels of free triiodothyronine (FT3) and free thyroxine (FT4). The exact prevalence of this condition in Italy is not known. The aim of this study was to assess the presence of subclinical hypothyroidism in 1001 subjects living in the Milan area (age 17-89) and apparently free from thyroid pathology. This sample which had applied to a large laboratory centre (Centro Diagnostico Italiano, Milano) for a routine check-up was seen from April to July 1996. A serum TSH assay was performed using a highly sensitive immunoenzymatic method, while an FT3 and FT4 assay was performed by means of a radioimmunologic method using commercial kits. The prevalence of subclinical hypothyroidism in the total population proved to be 4.7% (95% CI-Confidence Interval: 3.4-6.0). Sex stratification showed a prevalence of 6.1% in females and 3.4% in males. Prevalence in patients up to 65 was 4.2%. This value increased up to 8.0% in subjects over 65. By combining these variables, in females >65 prevalence increased to 11.3%. Overall, symptoms typical of overt hypothyroidism were found in 58.3% of patients suffering from subclinical hypothyroidism and in 39.9% of healthy subjects (p<0.02). The results of this study show that there is a significant presence (about 5%) of subclinical hypothyroidism in this population and that its frequency is more than doubled in women over 65. Early treatment might reduce the progression to overt hypothyroidism. The benefits of such a procedure were recently suggested by a decision making modelling approach applied to the Italian environment.