Treatment of benign nodular goitre with mildly suppressive doses of L-thyroxine: effects on bone mineral density and on nodule size

Network analysis of osteoporosis provides a global view of associated comorbidities and their temporal relationships

We performed comorbidity-network analysis to obtain global view of comorbidity related with osteoporosis. We selected 10000-patients with osteoporosis registered in the National-Health-Insurance Service cohort-database. We found 45-significant disease-clusters. Of these, 14-disease-clusters were related to fra, while 10 were related to musculoskeletal diseases. Our findings will serve as basic data for further studies.

PURPOSE

Osteoporosis causes devastating fractures; however, its exact etiology remains unknown. Elucidating associated comorbidities and their temporal relationships could provide better insights into its pathogenesis. Comorbidity-network analysis was performed to obtain global view of these associations.

METHODS

We randomly selected 10000-patients with osteoporosis registered in the National-Health-Insurance Service cohort-database. These patients were identified using ICD-10 codes M81-M82, which represent osteoporosis without pathological fractures. Control group was created through propensity score matching. The comorbidities in each group were grouped into similar classifications to form "disease cluster"; 126 such clusters were identified. To create a comorbidity network, we selected disease clusters with high associations (i.e., odds ratios and relative risks ranked in the upper 50^th percentile). To identify the temporal relationships between these clusters and osteoporosis, trajectories of directions were identified.

RESULTS

Finally, we found 45 significant disease clusters. Of these, 14 disease clusters were related to fractures or injuries, while 10 were related to musculoskeletal diseases. Temporal analysis revealed that 15 disease clusters preceded osteoporosis; these included the following three with the strongest associations: "other fracture", "disorders of bone density and structure (M83-M85)", and "sequelae of injuries of neck and trunk (T91)". Thirty disease clusters followed osteoporosis; these included the following three with the strongest associations: "spine fracture," "spondylopathies (M45-M49)", and "pelvic region and thigh fracture,".

CONCLUSION

We obtained a global view of the osteoporosis comorbidity network, which is otherwise difficult to achieve through study of individual diseases. Our findings will serve as the basic data for further studies.

Effect of Thyroxine and Thyrotropin on Bone Mineral Density in Postmenopausal Women: A Systematic Review

The effect of thyroid hormones on bone mineral density in postmenopausal women has been reported but is not completely established. To better understand this relationship, this systematic review of the reported association, differences, and effects of thyroxine and/or thyrotropin levels on bone mineral density was conducted. An electronic literature search was conducted on MEDLINE, PMC, Google Scholar, Cochrane Library, and Science Direct from inception to April 2022; 20 studies were identified which include five quasi-experimental studies, three community cohort studies, and 12 hospital-based cross-sectional studies. Following an extensive evaluation, it was difficult to conclusively determine the association or effect of thyroxine or thyrotropin levels on bone mineral density in postmenopausal women. It is therefore suggested to conduct additional non-randomized or randomized control studies on this topic for the benefit of postmenopausal women. Particular attention should be given to the adjustment of age, body mass index, smoking status, alcohol consumption, and dietary calcium in future research on this topic for rigorous analysis.

[Clinical practice guidelines for evaluation and treatment of osteoporosis associated to endocrine and nutritional conditions. Bone Metabolism Working Group of the Spanish Society of Endocrinology]

OBJECTIVE

To provide practical recommendations for evaluation and treatment of osteoporosis associated to endocrine diseases and nutritional conditions.

PARTICIPANTS

Members of the Bone Metabolism Working Group of the Spanish Society of Endocrinology, a methodologist, and a documentalist.

METHODS

Recommendations were formulated according to the GRADE system (Grading of Recommendations, Assessment, Development, and Evaluation) to describe both the strength of recommendations and the quality of evidence. A systematic search was made in MEDLINE (Pubmed), using the following terms associated to the name of each condition: AND "osteoporosis", "fractures", "bone mineral density", and "treatment". Papers in English with publication date before 18 October 2011 were included. Current evidence for each disease was reviewed by two group members, and doubts related to the review process or development of recommendations were resolved by the methodologist. Finally, recommendations were discussed in a meeting of the Working Group.

CONCLUSIONS

The document provides evidence-based practical recommendations for evaluation and management of endocrine and nutritional diseases associated to low bone mass or an increased risk of fracture. For each disease, the associated risk of low bone mass and fragility fractures is given, recommendations for bone mass assessment are provided, and treatment options that have shown to be effective for increasing bone mass and/or to decreasing fragility fractures are listed.

Bone demineralization in postmenopausal women: role of anamnestic risk factors

This study evaluated the effects of LT4 administration on the bone mineral density (BMD) in physiological postmenopausal women after two years of continuative treatment. 110 postmenopausal women with nodular goiter aged between 50 and 55 years were examined before and after 2 years of therapy with a fixed dose of LT4 (1.6 mcg/kg/die) for the treatment of nodular thyroid disease. The results showed that the patients on treatment with LT4 have a slight, but significant reduction of the BMD after 2 years of treatment, associated with increased serum levels of alkaline phosphatase and urinary excretion of hydroxyproline, confirming our data conducted on the same group after one year of therapy. Comparison between patients receiving LT4 (group A) or not (group B) showed that group A patients had significantly lower BMD. We demonstrated the statistically significant influence of the following risk factors on BMD: (1) body mass index <19 kg/m(2); (2) the onset of menarche after the age of 15 years; (3) positive history for period of amenorrhoea; (4) nulliparity.

Thyroxine suppression therapy for benign, non-functioning solitary thyroid nodules: a quality-effects meta-analysis

Levothyroxine (LT4) suppressive therapy for solitary thyroid nodules is not popularly advocated presently because its clinical efficacy and safety are currently considered controversial. This meta-analysis aims to address efficacy issues by using rigorous methods to arrive at a pooled estimate. On the basis of the analysis, it is estimated that LT4 therapy is clearly associated with up to a two-fold increase in the chance of nodule reduction. This translates to a number needed to treat (NNT) of 6 or a 50% decrease in the risk of cancer given nodule reduction. Keeping this definition of efficacy in mind and a low incidence of adverse events with low level LT4 suppression, such an intervention might be appropriate in patients selected on the basis of a low risk for adverse effects.

Osteoporosis and thyrotropin-suppressive therapy: reduced effectiveness of alendronate

BACKGROUND

Many reports of the effect of exogenous thyroxine therapy on bone mineral density (BMD) show a relationship between excess thyroid hormone administration and osteoporosis. The aim of this study was to evaluate the effect of antibone resorptive agents, in particular alendronate (ALN) on BMD in postmenopausal osteoporotic women with thyroid carcinoma who were receiving long-term thyrotropin (TSH)-suppressive therapy with thyroxine.

METHODS

Seventy-four postmenopausal women with low BMD (T-score < or =-2.5) and differentiated thyroid carcinoma on long-term TSH-suppressive therapy (TSH > or =0.05 and < or =0.1 microU/mL) for about 3-9 years were selected for the study. The patients were divided into three groups according to the length of levothyroxine (LT(4)) treatment prior to the beginning of the study: group A (TSH-suppressive therapy for about 3 years), group B (for about 6 years), and group C (for about 9 years). These patients were compared with 74 matched women not taking LT(4). All patients and controls were treated with bisphosphonates, calcium, and vitamin D for 2 years and evaluated.

RESULTS

After 24 months of treatment group A showed a 7.8% increase in lumbar BMD; group B, a 4.6% increase; and group C, a 0.86% increase. In the control group BMD increased 8.2%. A significant difference was found in both lumbar and femoral BMD increase among the three groups: group C had a lower BMD increase than group A (p < 0.001) and B (p < 0.001).

CONCLUSIONS

In postmenopausal women who were receiving adequate amounts of calcium and vitamin D in their diet ALN was less effective for those who were also receiving TSH-suppressive doses of LT(4) for either 6 or 9 years. The positive effect of ALN on BMD was less for longer periods of LT(4) treatment. It seems likely that other bisphosphonates would also be less effective in increasing BMD in postmenopausal women receiving TSH-suppressing doses of LT(4).

Levothyroxine therapy in preventing nodular recurrence after hemithyroidectomy: a retrospective study

AIM

To determine the effect of levothyroxine (L-T4) therapy on the recurrence rate of nodular disease in patients previously treated with lobectomy for benign nodular goiter.

METHODS

Two hundred and thirty-tree patients (38 males, 195 females; age 49.9+/-13.1 yr) with no post-surgical evidence of nodular disease in the remnant, were followed- up yearly with serum TSH and ultrasound (US). Nodular recurrence was defined as a lesion of at least 5 mm at US. Patients were divided in 2 groups based on whether or not they had been treated with L-T4 after surgery: Group 1 (45 patients) who did not receive any L-T4, and Group 2 (188 patients) treated with L-T4. Group 2 was further subdivided in Group 2a (123 patients) receiving L-T4 substitutive therapy (TSH>or=0.5 and <or=3 mUI/l) and Group 2b (65 patients) receiving L-T4 at TSH-suppressive dose (TSH<0.5 mUI/l).

RESULTS

Mean observation period was 5.8+/-4.7 yr. Overall, 71 out of 233 (30.5%) patients experienced recurrence of thyroid nodular disease: 29 patients (64.4%) in Group 1, 24 (19.5%) patients in Group 2a, and 18 (27.7%) patients in Group 2b. The recurrence rate was significantly lower (p<0.001) in Group 2 compared with Group 1, but no significant difference was observed between Groups 2a and 2b.

CONCLUSION

In patients who have undergone hemithyroidectomy for benign monolobar nodular disease, L-T4 therapy may prevent recurrence of nodular disease. TSH suppression may not be required for prevention of recurrence in the remnant thyroid tissue.

The clinical significance of subclinical thyroid dysfunction

Subclinical thyroid disease (SCTD) is defined as serum free T(4) and free T(3) levels within their respective reference ranges in the presence of abnormal serum TSH levels. SCTD is being diagnosed more frequently in clinical practice in young and middle-aged people as well as in the elderly. However, the clinical significance of subclinical thyroid dysfunction is much debated. Subclinical hyper- and hypothyroidism can have repercussions on the cardiovascular system and bone, as well as on other organs and systems. However, the treatment and management of SCTD and population screening are controversial despite the potential risk of progression to overt disease, and there is no consensus on the thyroid hormone and thyrotropin cutoff values at which treatment should be contemplated. Opinions differ regarding tissue effects, symptoms, signs, and cardiovascular risk. Here, we critically review the data on the prevalence and progression of SCTD, its tissue effects, and its prognostic implications. We also examine the mechanisms underlying tissue alterations in SCTD and the effects of replacement therapy on progression and tissue parameters. Lastly, we address the issue of the need to treat slight thyroid hormone deficiency or excess in relation to the patient's age.

Thyroid and bone

This article provides a summary of the numerous interactions between the thyroid gland and the skeleton, in the normal state, in disorders of thyroid function and as a result of thyroid malignancy. It recaps the current understanding of bone growth and development in the endochondral growth plate and the normal mechanisms of mature bone remodeling. The actions of thyroid hormones on these processes are described, and the clinical impact of thyroid disorders and their treatments on the bone are summarized. Finally, our current understanding of the physiology of bone metastases from thyroid cancer is covered.

Need for an Individualized and Aggressive Management of Multinodular Goiters of Endemic Zones by Specially Trained Surgeons: Experience in Western Nepal

BACKGROUND

The goals of the present study were to explore the presentation of multinodular goiter (MNG) and solitary thyroid nodules (STN) in the sub-Himalayan belt, including the risk of malignancy, and to evaluate whether specialized surgeon training in endocrine surgery has an effect on reducing complications.

METHODS

This retrospective study (1998-2003) analyzed 624 patients with thyroid disorders seen in the thyroid clinic of a tertiary care hospital in western Nepal. The findings included 67.7% (n = 423: euthyroid, 297, toxic, 126) multinodular goiters (MNG) and 18.5% (n = 116) STN. Rest of patients of other thyroid disorders were excluded from the study. Ultrasonography and fine-needle aspiration cytology (FNAC) were the available diagnostic adjuncts. To evaluate the role of surgeon training, outcomes were compared between patients cared for by surgeons specially trained in endocrine surgery and those who were not. Prognostic markers indicated aggressiveness of cancers.

RESULTS

Of the 539 MNG and STN patients in this series, 236 underwent operation. Of these, 25.7% (139/539) were toxic, and 11.31% had associated carcinoma. Aggressive cancers, like poorly differentiated (4.9%) and anaplastic types (18%), were more common than in series of patients from iodine-sufficient regions. Patients 40-55 years of age were more likely to have toxicity, and those > 60 years of age were more likely to have aggressive cancers. Postoperative complication rates were lower in the group treated by surgeons who had special training in endocrine surgery.

CONCLUSIONS

There is a higher incidence of toxicity and malignancy in MNG in an endemic goiter zone. The limited diagnostic and therapeutic facilities in the region under study warrant a high degree of clinical suspicion and judgment, sound knowledge of thyroid physiology, thorough interpretation of hormone test results, and meticulous surgical techniques. The treatment must be individualized with consideration of humanitarian and socioeconomic factors, without compromising the quality of care and its long-term consequences. Aggressive management of malignancy and toxicity with total thyroidectomy is needed as primary therapy in many instances. However, subtotal excision is more useful in carefully selected cases with a small remnant. Specialized training in thyroid surgery appears to be valuable in reducing complications.

A clinical and therapeutic approach to thyrotoxicosis with thyroid-stimulating hormone suppression only

Subclinical hyperthyroidism is defined as normal serum free thyroxine (T4) and triiodothyronine (T3) concentrations and persistently suppressed thyroid stimulating hormone (TSH) concentrations. The most common cause of subclinical hyperthyroidism is the use of suppressive doses of L-thyroxine for treatment of hypothyroidism or, less commonly, diffuse nontoxic goiter or thyroid carcinoma (exogenous subclinical hyperthyroidism). Endogenous subclinical hyperthyroidism may be caused by a variety of thyroid disorders that result in overproduction and release of thyroid hormones from the gland with normal/high 24-hour thyroid radioiodine uptake or by inflammation in the thyroid resulting in release of excess thyroid hormones and low 24-hour thyroid radioiodine uptake. Several groups have investigated whether persistent endogenous or exogenous subclinical hyperthyroidism, like overt hyperthyroidism, causes symptoms, adverse effects on the cardiovascular and the skeletal systems, and increased mortality, whether endogenous subclinical hyperthyroidism evolves to overt thyrotoxicosis, and whether or not it should be treated. The present report reviews the most important and recent studies of subclinical hyperthyroidism and attempts to draw conclusions based upon the literature and the authors' experience.

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.

The molecular actions of thyroid hormone in bone

Thyroid hormone (T(3)) is essential for the normal development of endochondral and intramembranous bone and plays an important role in the linear growth and maintenance of bone mass. Childhood T(3) deficiency results in retardation of skeletal development and growth arrest, whereas T(3) excess leads to accelerated growth and bone formation. In adult thyrotoxicosis, there is increased bone remodelling, characterized by an imbalance between bone resorption and formation, which results in net bone loss and an increased risk for posteoporotic fracture. These clinical observations demonstrate the importance of T(3) in skeletal development and metabolism. Nevertheless, the molecular mechanisms of T(3) action in bone are poorly understood. Here, we provide an overview of T(3) regulation of chondrocytes, osteoblasts and osteoclasts, and the actions of thyroid hormone receptor (TR) isoforms in skeletal development. The possible roles of T(3) and TRs in nuclear receptor crosstalk, prereceptor ligand metabolism, heparan sulfate proteoglycan synthesis and angiogenesis are also considered.