The impact of age on quality of life and frailty outcomes after parathyroidectomy in patients with primary hyperparathyroidism

OBJECTIVE

Parathyroidectomy (PTx) improves quality of life (QoL) in patients with primary hyperparathyroidism (PHPT). Whether this effect is modified according to the patients' age is unknown. The aim of this study was to evaluate the impact of age on the effect of PTx on QoL and frailty in patients with PHPT, six months post-PTx.

METHODS

This was a prospective cohort study, including patients with PHPT, admitted from January 2016 to December 2019, divided into two categories: younger (≤ 65 years old) and older (> 65 years old). QoL was assessed with the Pasieka questionnaire (PAS-Q) two days pre- and six months post-operatively. Frailty was also assessed at the same time intervals, with the Frailty Index (FI).

RESULTS

One hundred and thirty-four patients (younger group: 96 patients, mean age 50.4 ± 9.8 years; older group: 38 patients, mean age 72.1 ± 4.9 years) were included. PTx resulted in a significant reduction in PAS-Q score in both groups. Notably, a greater reduction in "mood swings", "irritability", "itchy skin" and "feeling thirsty" PAS-Q domains was observed in the younger group. In contrast, a greater decrease in "bone pain", "tiredness", "weakness", "joint pain", "getting off chair" and "headaches" items was observed in the older group. Moreover, PTx led to a decrease in FI only in this group.

CONCLUSIONS

PTx leads to an improvement in QoL both in older (> 65 years) and younger (≤ 65 years) patients with PHPT, attributed to a differential effect on PAS-Q items. Frailty improves only in the older group.

Outcomes of Thyroid Dysfunction in People Aged Eighty Years and Older: An Individual Patient Data Meta-Analysis of Four Prospective Studies (Towards Understanding Longitudinal International Older People Studies Consortium)

Background: Subclinical and overt thyroid dysfunction is easily detectable, often modifiable, and, in younger age groups, has been associated with clinically relevant outcomes. Robust associations in very old persons, however, are currently lacking. This study aimed to investigate the associations between (sub-)clinical thyroid dysfunction and disability in daily living, cognitive function, depressive symptoms, physical function, and mortality in people aged 80 years and older. Methods: Four prospective cohorts participating in the Towards Understanding Longitudinal International older People Studies (TULIPS) consortium were included. We performed a two-step individual participant data meta-analysis on source data from community-dwelling participants aged 80 years and older from the Netherlands, New Zealand, United Kingdom, and Japan. Outcome measures included disability in daily living (disability in activities of daily living [ADL] questionnaires), cognitive function (Mini-Mental State Examination [MMSE]), depressive symptoms (Geriatric Depression Scale [GDS]), physical function (grip strength) at baseline and after 5 years of follow-up, and all-cause five-year mortality. Results: Of the total 2116 participants at baseline (mean age 87 years, range 80-109 years), 105 participants (5.0%) were overtly hypothyroid, 136 (6.4%) subclinically hypothyroid, 1811 (85.6%) euthyroid, 60 (2.8%) subclinically hyperthyroid, and 4 (0.2%) overtly hyperthyroid. Participants with thyroid dysfunction at baseline had nonsignificantly different ADL scores compared with euthyroid participants at baseline and had similar MMSE scores, GDS scores, and grip strength. There was no difference in the change of any of these functional measures in participants with thyroid dysfunction during five years of follow-up. Compared with the euthyroid participants, no 5-year survival differences were identified in participants with overt hypothyroidism (hazard ratio [HR] 1.0, 95% confidence interval [CI 0.6-1.6]), subclinical hypothyroidism (HR 0.9 [CI 0.7-1.2]), subclinical hyperthyroidism (HR 1.1 [CI 0.8-1.7]), and overt hyperthyroidism (HR 1.5 [CI 0.4-5.9]). Results did not differ after excluding participants using thyroid-influencing medication. Conclusions: In community-dwelling people aged 80 years and older, (sub-)clinical thyroid dysfunction was not associated with functional outcomes or mortality and may therefore be of limited clinical significance.

Incidence and Mortality of Myocardial Infarction and Stroke in Patients with Hyperthyroidism: A Nationwide Cohort Study in Korea

Background: Hyperthyroidism is associated with various cardiovascular risk factors. However, the relationship between hyperthyroidism and myocardial infarction (MI) or stroke has not been fully elucidated; only a few studies have investigated the association of hyperthyroidism with survival after MI or stroke. Methods: We included 59,021 hyperthyroid patients and a control cohort with 1,180,420 age- and sex-matched subjects from the Korean National Health Insurance database. Blood pressure, body mass index (BMI), glucose and cholesterol levels, and smoking history were obtained during National Health screening examination. We compared the incidence of MI, stroke, and survival after cardiovascular events between subjects with hyperthyroidism and the control cohort. Results: Subjects with hyperthyroidism had higher blood pressure, fasting glucose, and smoking rate, but lower cholesterol levels and a lower obesity rate compared with the control cohort. After adjusting these differences, as well as atrial fibrillation, hyperthyroidism was associated with increased risk of MI and ischemic stroke. Adjusted hazard ratios (HRs) for MI and ischemic stroke with hyperthyroidism was 1.16 [95% confidence interval, CI 1.03-1.30] and 1.12 [CI 1.04-1.20], respectively. In age-, sex-, and BMI-stratified analyses, an increased risk of MI and ischemic stroke remained significant in females, the older age group (≥50 years), and nonobese subjects (BMI <25 kg/m²), but not in males, the younger age group (<50 years), and obese subjects (BMI ≥25 kg/m²). The risk of hemorrhagic stroke was not different between subjects with hyperthyroidism and controls. Adjusted HRs for mortality in subjects with hyperthyroidism who developed MI, ischemic stroke, and hemorrhagic stroke were 1.11 ([CI 0.86-1.43], p = 0.44), 0.89 ([CI 0.75-1.05], p = 0.16), and 1.13 ([CI 0.88-1.47], p = 0.34), respectively. Conclusions: Hyperthyroidism is associated with increased risk of MI and ischemic stroke, independent of cardiovascular risk factors. This association is prominent in subjects with age ≥50 years, in females, and in the nonobese group. Hyperthyroidism did not significantly affect the mortality secondary to cardiovascular events.

Thyroid Status and Death Risk in US Veterans With Chronic Kidney Disease

OBJECTIVE

Given that patients with non-dialysis-dependent chronic kidney disease (NDD-CKD) have a disproportionately higher prevalence of hypothyroidism compared with their non-CKD counterparts, we sought to determine the association between thyroid status, defined by serum thyrotropin (TSH) levels, and mortality among a national cohort of patients with NDD-CKD.

PATIENTS AND METHODS

Among 227,422 US veterans with stage 3 NDD-CKD with 1 or more TSH measurements during the period October 1, 2004, to September 30, 2012, we first examined the association of thyroid status, defined by TSH categories of less than 0.5, 0.5 to 5.0 (euthyroidism), and more than 5.0 mIU/L, with all-cause mortality. We then evaluated 6 granular TSH categories: less than 0.1, 0.1 to less than 0.5, 0.5 to less than 3.0, 3.0 to 5.0, more than 5.0 to 10.0, and more than 10.0 mIU/L. We concurrently examined thyroid status, thyroid-modulating therapy, and mortality in sensitivity analyses.

RESULTS

In expanded case-mix adjusted Cox analyses, compared with euthyroidism, baseline and time-dependent TSH levels of more than 5.0 mIU/L were associated with higher mortality (adjusted hazard ratios [aHRs] [95% CI], 1.19 [1.15-1.24] and 1.23 [1.19-1.28], respectively), as were baseline and time-dependent TSH levels of less than 0.5 mIU/L (aHRs [95% CI], 1.18 [1.15-1.22] and 1.41 [1.37-1.45], respectively). Granular examination of thyroid status showed that incrementally higher TSH levels of 3.0 mIU/L or more were associated with increasingly higher mortality in baseline and time-dependent analyses, and TSH categories of less than 0.5 mIU/L were associated with higher mortality (reference, 0.5-<3.0 mIU/L) in baseline analyses. In time-dependent analyses, untreated and undertreated hypothyroidism and untreated hyperthyroidism were associated with higher mortality (reference, spontaneous euthyroidism), whereas hypothyroidism treated-to-target showed lower mortality.

CONCLUSION

Among US veterans with NDD-CKD, high-normal TSH (≥3.0 mIU/L) and lower TSH (<0.5 mIU/L) levels were associated with higher death risk. Interventional studies identifying the target TSH range associated with the greatest survival in patients with NDD-CKD are warranted.

Excess Mortality in Treated and Untreated Hyperthyroidism Is Related to Cumulative Periods of Low Serum TSH

INTRODUCTION AND AIM

Cumulative time-dependent excess mortality in hyperthyroid patients has been suggested. However, the effect of antithyroid treatment on mortality, especially in subclinical hyperthyroidism, remains unclarified. We investigated the association between hyperthyroidism and mortality in both treated and untreated hyperthyroid individuals.

PATIENTS AND METHODS

Register-based cohort study of 235,547 individuals who had at least one serum thyroid-stimulating hormone (TSH) measurement in the period 1995 to 2011 (7.3 years median follow-up). Hyperthyroidism was defined as at least two measurements of low serum TSH. Mortality rates for treated and untreated hyperthyroid subjects compared with euthyroid controls were calculated using multivariate Cox regression analyses, controlling for age, sex, and comorbidities. Cumulative periods of decreased serum TSH were analyzed as a time-dependent covariate.

RESULTS

Hazard ratio (HR) for mortality was increased in untreated [1.23; 95% confidence interval (CI), 1.12 to 1.37; P < 0.001], but not in treated, hyperthyroid patients. When including cumulative periods of TSH in the Cox regression analyses, HR for mortality per every 6 months of decreased TSH was 1.11 (95% CI, 1.09 to 1.13; P < 0.0001) in untreated hyperthyroid patients (n = 1137) and 1.13 (95% CI, 1.11 to 1.15; P < 0.0001) in treated patients (n = 1656). This corresponds to a 184% and 239% increase in mortality after 5 years of decreased TSH in untreated and treated hyperthyroidism, respectively.

CONCLUSIONS

Mortality is increased in hyperthyroidism. Cumulative periods of decreased TSH increased mortality in both treated and untreated hyperthyroidism, implying that excess mortality may not be driven by lack of therapy, but rather inability to keep patients euthyroid. Meticulous follow-up during treatment to maintain biochemical euthyroidism may be warranted.

Acute cardiovascular events and all-cause mortality in patients with hyperthyroidism: a population-based cohort study

OBJECTIVE

Several studies have shown an increased risk for cardiovascular disease (CVD) in hyperthyroidism, but most studies have been too small to address the effect of hyperthyroidism on individual cardiovascular endpoints. Our main aim was to assess the association among hyperthyroidism, acute cardiovascular events and mortality.

DESIGN

It is a nationwide population-based cohort study. Data were obtained from the Danish Civil Registration System and the Danish National Patient Registry, which covers all Danish hospitals. We compared the rate of all-cause mortality as well as venous thromboembolism (VTE), acute myocardial infarction (AMI), ischemic and non-ischemic stroke, arterial embolism, atrial fibrillation (AF) and percutaneous coronary intervention (PCI) in the two cohorts. Hazard ratios (HR) with 95% confidence intervals (95% CI) were estimated.

RESULTS

The study included 85 856 hyperthyroid patients and 847 057 matched population-based controls. Mean follow-up time was 9.2 years. The HR for mortality was highest in the first 3 months after diagnosis of hyperthyroidism: 4.62, 95% CI: 4.40-4.85, and remained elevated during long-term follow-up (>3 years) (HR: 1.35, 95% CI: 1.33-1.37). The risk for all examined cardiovascular events was increased, with the highest risk in the first 3 months after hyperthyroidism diagnosis. The 3-month post-diagnosis risk was highest for atrial fibrillation (HR: 7.32, 95% CI: 6.58-8.14) and arterial embolism (HR: 6.08, 95% CI: 4.30-8.61), but the risks of VTE, AMI, ischemic and non-ischemic stroke and PCI were increased also 2- to 3-fold.

CONCLUSIONS

We found an increased risk for all-cause mortality and acute cardiovascular events in patients with hyperthyroidism.

Thyroid Functional Disease and Mortality in a National Peritoneal Dialysis Cohort

CONTEXT AND OBJECTIVE

End-stage renal disease patients have a higher risk of thyroid disease compared with those without kidney disease. Although thyroid dysfunction is associated with higher death risk in the general population and those undergoing hemodialysis, little is known about the effect of thyroid disease upon mortality in patients treated with peritoneal dialysis (PD).

DESIGN, SETTING, PARTICIPANTS, AND MAIN OUTCOME

We examined the association of thyroid status, assessed by serum TSH, with all-cause mortality among PD patients from a large national dialysis organization who underwent one or more TSH measurements over 5 years (January 2007 to December 2011). Thyroid status was categorized as overt-hyperthyroid, subclinical-hyperthyroid, low-normal, high-normal, subclinical-hypothyroid, and overt-hypothyroid range (TSH < 0.1, 0.1–<0.5, 0.5–<3.0, 3.0–<5.0, 5.0–<10.0, and ≥10.0 mIU/L, respectively). We examined the association between TSH and mortality using case mix–adjusted time-dependent Cox models to assess short-term thyroid function–mortality associations and to account for changes in thyroid function over time.

RESULTS

Among 1484 patients, 7 and 18% had hyperthyroidism and hypothyroidism, respectively, at baseline. We found that both lower and higher time-dependent TSH levels were associated with higher mortality (reference: TSH, 0.5-<3.0 mIU/L): adjusted hazard ratios (95% confidence intervals) 2.09 (1.08-4.06), 1.53 (0.87-2.70), 1.05 (0.75-1.46), 1.63 (1.11-2.40), and 3.11 (2.08-4.63) for TSH levels, <0.1, 0.1-<0.5, 0.5-<3.0, 3.0-<5.0, 5.0-<10.0, and ≥10.0 mIU/L, respectively.

CONCLUSION

Time-dependent TSH levels < 0.1 mIU/L and ≥ 5.0 mIU/L were associated with higher mortality, suggesting hyper- and hypothyroidism carry short-term risk in PD patients. Additional studies are needed to determine mechanisms underlying the thyroid dysfunction-mortality association, and whether normalization of TSH with treatment ameliorates mortality in this population.

Association Between Serum Thyrotropin Levels and Mortality Among Euthyroid Adults in the United States

BACKGROUND

Low thyroid function within the euthyroid range, as well as overt and subclinical hypothyroidism, reportedly increases the risk of cardiovascular disease and mortality. However, the association between low normal thyroid function and mortality remains controversial. This study was performed to elucidate the association between low normal thyroid function and all-cause and/or cause-specific mortalities among U.S. adults.

METHODS

A prospective cohort study was conducted using a nationally representative sample of 12,584 U.S. adults aged ≥20 years with thyrotropin (TSH) levels within the reference range from the National Health and Nutrition Examination Survey (NHANES) III (1988-1994). Associations between TSH tertiles (high, medium, and low normal TSH groups) and mortalities (all-cause, cardiovascular, and cancer) were investigated using multivariable Cox models. Stratum-specific analyses were estimated within subgroups defined according to sex (male or female) and baseline age (age <60 years or age ≥60 years). Further, the same analysis was conducted using continuous NHANES 2001-2002, 2007-2008, and 2009-2010 cohorts, which included data on free thyroxine levels.

RESULTS

The median follow-up period was 19.1 years, with 3395 all-cause deaths. A significantly higher risk of all-cause mortality (adjusted hazard ratio [HR] 1.27; [confidence interval (CI) 1.10-1.47]), and cardiovascular mortality (HR 1.30 [CI 1.02-1.67]), and cancer mortality (HR 1.43 [CI 1.01-2.01]) was observed in the high normal TSH group than in the medium normal TSH group. Additionally, the low normal TSH group had an increased risk of all-cause mortality. In stratum-specific analyses, a significant association was found between high normal TSH levels and all-cause mortality among males, females, and participants <60 years. Continuous NHANES cohorts demonstrated a non-significant increase in the HR for all-cause mortality in the high normal TSH group.

CONCLUSIONS

High normal TSH levels compared with medium normal TSH levels were associated with increased risk of all-cause, cardiovascular, and cancer mortalities over a long-term follow-up period among U.S. adults. This study indicates that the reference range for TSH levels may require re-evaluation.

Cardiac death risk in diabetic haemodialysis patients increased due to thyroid problems

A prospective study found that diabetic haemodialysis patients' subclinical hyperthyroidism and euthyroid sick syndrome might increase the risk of sudden cardiac-related deaths. Dr Christiane Drechsler, of University Hospital Würzburg in Würzburg, Germany, and colleagues conducted a study that included 1000 patients undergoing haemodialysis for diabetes. Of those patients, 78.1% had euthyroidism, 13.7% had subclinical hyperthyroidism, 1.6% had subclinical hypothyroidism and 5.4% had euthyroid sick syndrome.

Thyroid dysfunction and ischemic heart disease--clinical correlations, progressive implications and impact on the prognosis

Thyroid dysfunctions are associated with systolic and diastolic heart dysfunction, hypertension, rhythm disorders, etc. Clinically significant hyperthyroidism and hypothyroidism may have an impact on the patients with ischemic heart disease.

OBJECTIVES

Investigation of the risk of developing ischemic heart disease, of the evolution and prognosis in relation to the entire spectrum of thyroid dysfunctions.

MATERIALS AND METHODS

All participants included in the study were selected from among subjects with heart disorders who were controlled with concern to the thyroid hormonal condition and who hadn't been treated previously for thyroid functional disorders. Based on these criteria we defined a study group made out of 791 subjects, divided into five lots based on the level of thyroid hormones. Once the group was formed, we conducted evaluations of the cardiovascular and thyroid status at 6 and 12 months, respectively.

RESULTS

In the witness lot, during monitoring 49% of the patients showed an ischemic heart disease. The main risk factors were: heart frequency of over 80 beats/min (RR = 1.83), age over 60 (RR = 1.47), female sex (RR = 1.21) and values of triglycerides over 160 mg/dl (RR = 1.23). In the group of patients with overt clinic hyperthyroidism, during monitoring 46.1% showed ischemic heart disease. The main risk factors were: heart frequency over 80 beats/min (RR = 2.41), age over 60 (RR = 1.67), high level of LDL-cholesterol (RR = 1.53) and female sex (RR = 1.31). Among the patients with overt clinical hyperthyroidism, during monitoring 53.3% showed ischemic heart disease. The main risk factors identified were: heart frequency over 80 beats/min (RR = 2.01), age over 60 (RR = 1.42), high levels of triglycerides (RR = 1.42) and LDL-cholesterol (RR = 1.32), as well as the presence of hypertension in the health records (RR = 1.31).

CONCLUSIONS

Thyroid dysfunction is a common clinical condition with a key role in the regulation of the cardiovascular system and may contribute to the evolution of the ischemic heart disease and which should be taken into consideration when patients with heart disease are treated. In this light, thyroid function needs to be evaluated for all patients with a risk for ischemic heart disease.

Thyroid function tests and mortality in aged hospitalized patients: a 7-year prospective observational study

CONTEXT

Several alterations in thyroid function test (TFT) results have been associated with mortality in elderly patients.

OBJECTIVE

Our aim was to investigate the relationship between TFT results and all-cause and cardiovascular (CV) mortality in aged hospitalized patients.

DESIGN

A 7-year prospective observational study was conducted. TFTs were performed at hospital admission, and mortality was registered in the follow-up period.

PATIENTS

Participants were 404 patients aged >65 years admitted to the Department of Geriatrics, Hospital General, Segovia, Spain, for any reason during 2005.

MAIN OUTCOME MEASURES

The study evaluated the association between TFT results and mortality from all causes and CV diseases.

METHODS

TSH, free T₄, and free T₃ (FT₃) were measured on the first day of admission. In-hospital and total survival times, number of deaths, and all-cause and CV mortality were registered until the census date on January 1, 2012.

RESULTS

During the study, 323 patients (80%) died. Kaplan-Meier analysis showed that median survival time for all-cause mortality was significantly lower in patients in the first tertile of serum FT₃, in the first tertile of TSH, and in the first tertile of serum free T₄ concentrations. Multivariate adjusted Cox regression analysis showed that the history of cancer (hazard ratio, 1.60; 95% confidence interval, 1.12-2.28; P = .009), age (1.03; 1.01-1.06; P = .003), and FT₃ levels (0.72; 0.63-0.84; P < .001) were significant factors related to all-cause mortality. The cause of death was known in 202 patients. Of this group, 61 patients (30.2%) died of CV disease. Patients in the first tertile of TSH and FT₃ exhibited a significant higher mortality due to CV disease. In the adjusted Cox regression analysis, FT₃ was a significant predictor of CV mortality (0.76; 0.63-0.91; P = .004).

CONCLUSIONS

Alterations in TFT results during hospitalization are associated with long-term mortality in elderly patients. In particular, low FT₃ levels are significantly related to all-cause and CV mortality.

Higher free thyroxine levels are associated with all-cause mortality in euthyroid older men: the Health In Men Study

OBJECTIVE

Thyroid dysfunction predicts poorer health outcomes, but the relationship between thyroid hormone levels within the reference range and mortality in older adults remains unclear. In this study, we examined the associations between the concentrations of free thyroxine (FT4) and TSH and all-cause mortality in older men without thyroid disease.

SUBJECTS AND METHODS

We performed a longitudinal study in community-dwelling men aged 70-89 years. Men with thyroid disease or taking thyroid-related medications were excluded. Baseline FT4 and TSH levels were assayed. Incident deaths were ascertained using data linkage.

RESULTS

There were 3885 men without thyroid disease followed for (means.d.) 6.41.5 years, during which time 837 had died (21.5%). men who had died had higher baseline ft4 levels (16.22.3 vs 15.82.1 pmol/l, p0.001), but comparable tsh levels (2.41.5 vs 2.31.5 miu/l, P=0.250). After accounting for age, smoking, physical factors and medical comorbidities, higher circulating ft4 levels predicted all-cause mortality (quartile Q4 vs quartiles Q1Q3: FT4 levels ≥ 17.32 vs <17.32 pmol/l: adjusted hazard ratio (HR)=1.19, 95% CI=1.02-1.39, P=0.025). TSH levels did not predict mortality. After excluding men with subclinical hyperthyroidism or hypothyroidism, there were 3442 men and 737 who had died (21.4%). In these men, higher FT4 levels remained independently associated with all-cause mortality (quartile Q4 vs quartiles Q1-Q3: adjusted HR=1.19, 95% CI=1.02-1.41, P=0.032).

CONCLUSIONS

Higher FT4 levels are associated with all-cause mortality in euthyroid older men, independently of conventional risk factors and medical comorbidities. Additional research is needed to determine whether or not this relationship is causal and to clarify the utility of thyroid function testing to stratify mortality risk in ageing men.

Comparison of mortality in hyperthyroidism during periods of treatment with thionamides and after radioiodine

CONTEXT

Hyperthyroidism is common, but opinions regarding optimal therapy with antithyroid drugs or radioiodine (131-I) differ. There are no randomized trials comparing these options in terms of mortality.

OBJECTIVE

The aim of the study was to determine whether mortality associated with hyperthyroidism varies with treatment administered or other factors.

DESIGN, SETTING, AND PATIENTS

We conducted a prospective observational population-based study of 1036 subjects aged ≥ 40 years presenting to a single specialist clinic from 1989-2003 with a first episode of hyperthyroidism who were followed until June 2012.

INTERVENTIONS

Antithyroid drugs or radioiodine (131-I) were administered.

MAIN OUTCOME MEASURES

We compared causes of death with age-, sex-, and period-specific mortality in England and Wales and used within-cohort analysis of influence of treatment modality, outcome, disease etiology, severity and control, and comorbidities.

RESULTS

In 12 868 person-years of follow-up, 334 died vs 290.6 expected (standardized mortality ratio [SMR], 1.15 [95% confidence interval (CI),1.03-1.28]; P = .01). Increased all-cause mortality largely reflected increased circulatory deaths (SMR, 1.20 [95% CI, 1.01-1.43]; P = .04). All-cause mortality was increased for the person-years accumulated during thionamide treatment (SMR, 1.30 [95% CI, 1.05-1.61]; P = .02) and after 131-I not associated with hypothyroidism (SMR, 1.24 [95% CI, 1.04-1.46]; P = .01) but not during T₄ replacement for 131-I-induced hypothyroidism (SMR, 0.98 [95% CI, 0.82-1.18]; P = .85). Within-cohort analysis comparing mortality during thionamide treatment showed a similar hazard ratio (HR) for all-cause mortality when 131-I did not result in hypothyroidism (HR, 0.95 [95% CI, 0.70-1.29]), but reduced mortality with 131-I-induced hypothyroidism (HR, 0.70 [95% CI, 0.51-0.96]). Reduced mortality associated with hypothyroidism was seen only in those without significant comorbidities and not in those with other serious diseases. Atrial fibrillation at presentation (P = .02) and an increment of 10 pmol/L in serial free T₄ concentration during follow-up (P = .009) were independently associated with mortality.

CONCLUSIONS

Among hyperthyroid subjects aged 40 years or older, mortality was increased during periods of thionamide treatment and after radioiodine not resulting in hypothyroidism, but not during follow-up after radioiodine-induced hypothyroidism. Independent associations of mortality with atrial fibrillation and incomplete biochemical control during treatment indicate potential causative links with poor outcome.

Graves' disease and toxic nodular goiter are both associated with increased mortality but differ with respect to the cause of death: a Danish population-based register study

BACKGROUND

Hyperthyroidism has been associated with increased all-cause mortality. Whether the underlying cause of hyperthyroidism influences this association is unclear. Our objectives were to explore whether mortality risk and cause of death differ between Graves' disease (GD) and toxic nodular goiter (TNG).

METHODS

This is an observational cohort study, using record-linkage data from nationwide Danish health registers. A total of 1291 subjects with GD and 861 with TNG, treated in a hospital setting, were identified and followed for a mean period of 11 years. Cases were matched 1:4 with nonhyperthyroid controls with respect to age and sex. The hazard ratio (HR) for mortality was calculated using Cox regression analyses. All analyses were adjusted for comorbidity using the Charlson score.

RESULTS

Both GD (HR=1.42 [95% confidence interval (CI) 1.25-1.60]) and TNG (HR=1.22 [CI 1.07-1.40]) were associated with increased all-cause mortality. After stratification for the cause of death, GD was associated with increased mortality due to cardiovascular diseases (HR=1.49 [CI 1.25-1.77]) and lung diseases (HR=1.91 [CI 1.37-2.65]), whereas TNG was associated with increased cancer mortality (HR=1.36 [CI 1.06-1.75]). When analyzing mortality in GD using TNG individuals as controls, there was no significant difference in all-cause mortality between GD and TNG. However, GD was clearly associated with a higher cardiovascular mortality (HR=1.39 [CI 1.10-1.76]) compared to TNG.

CONCLUSION

Both GD and TNG, treated in a hospital setting, are associated with increased all-cause mortality. The causes of death differ between the two phenotypes, with cardiovascular mortality being significantly higher in GD.

Excess mortality in hyperthyroidism: the influence of preexisting comorbidity and genetic confounding: a danish nationwide register-based cohort study of twins and singletons

CONTEXT

Hyperthyroidism is associated with severe comorbidity, such as stroke, and seems to confer increased mortality. However, it is unknown whether this increased mortality is explained by hyperthyroidism per se, comorbidity, and/or genetic confounding.

OBJECTIVE

The objective of the study was to investigate whether hyperthyroidism is associated with an increased mortality and, if so, whether the association is influenced by comorbidity and/or genetic confounding.

METHODS

This was an observational cohort study using record-linkage data from nationwide Danish health registers. We identified 4850 singletons and 926 twins from same-sex pairs diagnosed with hyperthyroidism. Each case was matched with four controls for age and gender. The Charlson score was calculated from discharge diagnoses on an individual level to measure comorbidity. Cases and controls were followed up for a mean of 10 yr (range 0-31 yr), and the hazard ratio (HR) for mortality was calculated using Cox regression analyses.

RESULTS

In singletons there was a significantly higher mortality in individuals diagnosed with hyperthyroidism than in controls [HR 1.37; 95% confidence interval (CI) 1.30-1.46]. This persisted after adjustment for preexisting comorbidity (HR 1,28; 95% CI 1.21-1.36). In twin pairs discordant for hyperthyroidism (625 pairs), the twin with hyperthyroidism had an increased mortality compared with the corresponding cotwin (HR 1.43; 95% CI 1.09-1.88). However, this was found only in dizygotic pairs (HR 1.80; 95% CI 1.27-2.55) but not in monozygotic pairs (HR 0.95; 95% CI 0.60-1.50).

CONCLUSIONS

Hyperthyroidism is associated with an increased mortality independent of preexisting comorbidity. The study of twin pairs discordant for hyperthyroidism suggests that genetic confounding influences the association between hyperthyroidism and mortality.

How could we improve the increased cardiovascular mortality in patients with overt and subclinical hyperthyroidism?

Over the past five years several meta-analyses have evaluated the cardiovascular mortality in patients with hyperthyroidism. They assessed various studies in which different inclusion criteria were used for the analysis of the cardiovascular mortality. More selective criteria have been used in recent meta-analyses. Only prospective cohort studies were included and only cohorts using second and third generation TSH assays were chosen. In addition, only the studies where the TSH evaluation was repeated during the follow-up were selected. The results of these recent meta-analyses provide evidence that overt and subclinical hyperthyroidism, particularly in patients with undetectable serum TSH, may increase the cardiovascular mortality. However, still today, the results remain inconclusive and not sufficient enough to recommend treatment for patients with low-detectable serum TSH. The high cardiovascular risk and mortality in presence of thyroid hormone excess suggest that this dysfunction is an important health problem and requires guidelines for the treatment of patients at high cardiovascular risk. Rigorous studies are necessary to evaluate the effects of the various causes of hyperthyroidism on the clinical outcomes. Randomized controlled clinical trials are needed to assess the benefits of treatment to improve the cardiovascular mortality and morbidity of mild and overt hyperthyroidism.

Pediatric pulmonary arterial hypertension and hyperthyroidism: a potentially fatal combination

CONTEXT

Patients with pulmonary arterial hypertension (PAH) who develop hyperthyroidism are at risk for acute cardiopulmonary decompensation and death.

CASES AND SETTING

We present a series of eight idiopathic PAH/heritable PAH pediatric patients who developed hyperthyroidism between 1999 and 2011. Institutional Review Board approval was obtained; informed consent was waived due to the retrospective nature of the series. All eight patients were receiving iv epoprostenol; five of the eight patients presented with acute cardiopulmonary decompensation in the setting of hyperthyroidism. In the remaining three patients, hyperthyroidism was detected during routine screening of thyroid function tests. The one patient who underwent emergency thyroidectomy was the only survivor of those who presented in cardiopulmonary decline.

EVIDENCE SYNTHESIS

Aggressive treatment of the hyperthyroid state, including emergency total thyroidectomy and escalation of targeted PAH therapy and β-blockade when warranted, may prove lifesaving in these patients. Prompt thyroidectomy or radioactive iodine ablation should be considered for clinically stable PAH patients with early and/or mild hyperthyroidism to avoid potentially life-threatening cardiopulmonary decompensation.

CONCLUSIONS

Although the association between hyperthyroidism and PAH remains poorly understood, the potential impact of hyperthyroidism on the cardiopulmonary status of PAH patients must not be ignored. Hyperthyroidism must be identified early in this patient population to optimize intervention before acute decompensation. Thyroid function tests should be checked routinely in patients with PAH, particularly those on iv epoprostenol, and urgently in patients with acute decompensation or symptoms of hyperthyroidism.

Subclinical hyperthyroidism and the risk of cardiovascular events and all-cause mortality: an updated meta-analysis of cohort studies

OBJECTIVES

Whether subclinical hyperthyroidism (SCH) results in poor prognosis remains controversial. Our aim was to evaluate the association between SCH and the risk of cardiovascular disease (CVD), cardiovascular mortality, and all-cause mortality by conducting a meta-analysis of cohort studies.

METHODS

The PubMed and Embase databases were searched through November 2011 to identify studies that met pre-stated inclusion criteria. Relevant information for analysis was extracted. Either a fixed or a random effects model was used to calculate the overall combined risk estimates.

RESULTS

Seventeen cohort studies were included in this meta-analysis. The overall combined relative risks for individuals with SCH compared with the reference group were 1.19 (95% confidence interval (CI): 1.10 to 1.28) for CVD, 1.52 (95% CI: 1.08 to 2.13) for cardiovascular mortality, and 1.25 (95% CI: 1.00 to 1.55) for all-cause mortality. Subgroup analysis by sample source (community or convenience sample) showed that the significant association for cardiovascular and all-cause mortality only existed when pooling studies from convenience samples. Heterogeneity was observed when pooling studies on the association between SCH and cardiovascular and all-cause mortality. Sensitivity analysis showed omission of each individual study did not significantly change the pooled effects. No evidence of publication bias was observed.

CONCLUSIONS

Our findings demonstrated that SCH significantly increased the risk of CVD for the general population and the risk of cardiovascular and all-cause mortality for the individuals with other morbidities.

Subclinical hyperthyroidism and the risk of coronary heart disease and mortality

BACKGROUND

Data from prospective cohort studies regarding the association between subclinical hyperthyroidism and cardiovascular outcomes are conflicting.We aimed to assess the risks of total and coronary heart disease (CHD) mortality, CHD events, and atrial fibrillation (AF) associated with endogenous subclinical hyperthyroidism among all available large prospective cohorts.

METHODS

Individual data on 52 674 participants were pooled from 10 cohorts. Coronary heart disease events were analyzed in 22 437 participants from 6 cohorts with available data, and incident AF was analyzed in 8711 participants from 5 cohorts. Euthyroidism was defined as thyrotropin level between 0.45 and 4.49 mIU/L and endogenous subclinical hyperthyroidism as thyrotropin level lower than 0.45 mIU/L with normal free thyroxine levels, after excluding those receiving thyroid-altering medications.

RESULTS

Of 52 674 participants, 2188 (4.2%) had subclinical hyperthyroidism. During follow-up, 8527 participants died (including 1896 from CHD), 3653 of 22 437 had CHD events, and 785 of 8711 developed AF. In age- and sex-adjusted analyses, subclinical hyperthyroidism was associated with increased total mortality (hazard ratio[HR], 1.24, 95% CI, 1.06-1.46), CHD mortality (HR,1.29; 95% CI, 1.02-1.62), CHD events (HR, 1.21; 95%CI, 0.99-1.46), and AF (HR, 1.68; 95% CI, 1.16-2.43).Risks did not differ significantly by age, sex, or preexisting cardiovascular disease and were similar after further adjustment for cardiovascular risk factors, with attributable risk of 14.5% for total mortality to 41.5% forAF in those with subclinical hyperthyroidism. Risks for CHD mortality and AF (but not other outcomes) were higher for thyrotropin level lower than 0.10 mIU/L compared with thyrotropin level between 0.10 and 0.44 mIU/L(for both, P value for trend, .03).

CONCLUSION

Endogenous subclinical hyperthyroidism is associated with increased risks of total, CHD mortality, and incident AF, with highest risks of CHD mortality and AF when thyrotropin level is lower than 0.10 mIU/L.

A critical review and meta-analysis of the association between overt hyperthyroidism and mortality

BACKGROUND

Overt hyperthyroidism has been associated with cardiac arrhythmias, hypercoagulopathy, stroke, and pulmonary embolism, all of which may increase mortality. Some, but not all, studies show an increased mortality in patients with hyperthyroidism. This inconsistency may be due to differences in study design, characteristics of participants, or confounders. In order to test whether hyperthyroidism influences mortality, we performed a critical review and statistical meta-analysis.

METHODS

Based on an electronic PubMed search, using the Medical Subject Heading words such as hyperthyroidism, thyrotoxicosis, and mortality or survival, case-control and cohort studies were selected and reviewed. Using meta-analysis, an overall relative risk (RR) of mortality was calculated.

RESULTS

Eight studies fulfilled the inclusion criteria, six of which showed an increased all-cause mortality; seven studies, including 31,138 patients and 400,000 person years at risk, allowed calculation of mortality in a meta-analysis. Based on this, the RR of overall mortality was 1.21 (95% confidence interval: 1.05-1.38). Analyses including studies considering setting, treatment, and control for co-morbidity did not significantly alter this finding. As the measured heterogeneity (I(2)) ranges from 89.1 to 98.3%, which is much higher than the 50% generally viewed on as a threshold, the statistical heterogeneity is very pronounced in the included studies.

CONCLUSION

In patients diagnosed with hyperthyroidism, mortality is increased by ∼ 20%. Future studies need to address the cause of hyperthyroidism, impact of type of therapy, time dependency, as well as the potential influence of confounding or genetic susceptibility before the question of causality can be answered.

Endogenous subclinical thyroid disorders, physical and cognitive function, depression, and mortality in older individuals

OBJECTIVE

To what extent endogenous subclinical thyroid disorders contribute to impaired physical and cognitive function, depression, and mortality in older individuals remains a matter of debate.

DESIGN

A population-based, prospective cohort of the Longitudinal Aging Study Amsterdam.

METHODS

TSH and, if necessary, thyroxine and triiodothyronine levels were measured in individuals aged 65 years or older. Participants were classified according to clinical categories of thyroid function. Participants with overt thyroid disease or use of thyroid medication were excluded, leaving 1219 participants for analyses. Outcome measures were physical and cognitive function, depressive symptoms (cross-sectional), and mortality (longitudinal)

RESULTS

Sixty-four (5.3%) individuals had subclinical hypothyroidism and 34 (2.8%) individuals had subclinical hyperthyroidism. Compared with euthyroidism (n=1121), subclinical hypo-, and hyper-thyroidism were not significantly associated with impairment of physical or cognitive function, or depression. On the contrary, participants with subclinical hypothyroidism did less often report more than one activity limitation (odds ratio 0.44, 95% confidence interval (CI) 0.22-0.86). After a median follow-up of 10.7 years, 601 participants were deceased. Subclinical hypo- and hyper-thyroidism were not associated with increased overall mortality risk (hazard ratio 0.89, 95% CI 0.59-1.35 and 0.69, 95% CI 0.40-1.20 respectively).

CONCLUSIONS

This study does not support disadvantageous effects of subclinical thyroid disorders on physical or cognitive function, depression, or mortality in an older population.

Invited commentary: Cardiovascular mortality in subclinical hyperthyroidism: an ongoing dilemma

The association of endogenous subclinical hyperthyroidism (SHyper) with cardiovascular mortality is controversial. This may reflect the different causes of endogenous SHyper in the population studied due to differences in iodine intake, and different selection criteria, e.g. sex, age, and race, the cutoff for serum TSH level, the duration of follow-up, and the presence of co-morbidities. A small sample size of SHyper patients could have caused a low statistical power in some of these studies. In other studies, the results were not adjusted for relevant confounders. Importantly, various meta-analyses have also given conflicting results. This issue of the European Journal of Endocrinology contains two articles that address the association between endogenous SHyper and cardiovascular and total mortality: one study was conducted in a north-eastern German population and the other in a Japanese-Brazilian population. After adjusting for relevant confounders, there was no association between decreased serum TSH levels and all-cause and cardiovascular mortality in the Pomerania study; on the contrary, all-cause mortality and cardiovascular mortality were significantly higher for individuals with SHyper in the Japanese-Brazilian population. Interestingly, both studies had similar characteristics in terms of selection criteria and duration of follow-up. It remains controversial whether or not to treat middle-aged patients with low serum TSH levels. Large prospective randomized controlled double-blind studies of young and middle-aged patients with SHyper and without underlying cardiac disease are required to assess the potential benefits of treating endogenous SHyper in these age groups.

Mortality from thyroid cancer in patients with hyperthyroidism: the Theagenion Cancer Hospital experience

BACKGROUND

Thyroid carcinoma has been reported in patients operated for different types of hyperthyroidism and the probability of a hot nodule being malignant seems to be low. The aim of the present study was to explore the relationship between thyroid cancer, hyperthyroidism and outcome in a large cohort of patients who presented to a tertiary cancer centre in Northern Greece.

PATIENTS

Among 720 patients treated for thyroid cancer, 60 had a concomitant diagnosis of hyperthyroidism due to Graves' disease (n=14), solitary autonomous adenoma (n=17), or multinodular goiter (n=29). Adverse prognostic factors were common in patients with a previous history of hyperthyroidism at the time of diagnosis of thyroid cancer, including cases where the cancer was discovered coincidentally after thyroid surgery for hyperthyroidism and cases where tumor size was more than 10 mm.

RESULTS

In 10 out of 17 patients with hyperthyroidism due to solitary autonomous adenomas, the tumor was located within the hot nodule and two of these patients developed local and distant metastases and died from the disease 4 and 15 years after thyroidectomy.

CONCLUSION

Clinicians managing patients with hyperthyroidism need to be aware of the possible increased risk of thyroid cancer in this patient group.

Subclinical thyroid dysfunction and mortality: an estimate of relative and absolute excess all-cause mortality based on time-to-event data from cohort studies

OBJECTIVES

To what extent persons with subclinical hyper- or hypothyroidism are more (or less) likely to die than euthyroid control subjects remains a matter of controversy.

METHODS

We searched electronic reference databases up to July 31, 2007. Three reviewers independently assessed eligibility. Cohort studies published in full that reported data on the hazard ratio (HR) for mortality from all causes in persons with subclinical thyroid dysfunction versus euthyroid controls were included.

RESULTS

Based on seven cohorts including 290 participants with subclinical hyperthyroidism, random-effects models estimated that the pooled HR for all-cause mortality was 1.41 (95% confidence interval (CI), 1.12-1.79; P=0.004). Using the pooled HR and standard life-table methods applied to a US reference population, we estimated that a white US woman, when diagnosed with subclinical hyperthyroidism at age of 70, has an excess mortality of 1.5, 4.0, and 8.7% at 2, 5, and 10 years respectively after diagnosis. Likewise, a white US man has an excess mortality of 2.3, 5.7, and 10.7%. For the nine cohorts including 1580 participants with subclinical hypothyroidism, observed heterogeneity (Q test P=0.006; I(2)=63%) disappeared after pooling cohorts in predefined subgroups according to the presence or absence of a comorbid condition. In doing so, the pooled HR for all-cause mortality was 1.03 (95% CI, 0.78-1.35; P=0.83) in cohorts from the community and 1.76 (95% CI, 1.36-2.30; P<0.001) in cohorts of participants with comorbidities (P=0.014 for heterogeneity among study groups).

CONCLUSIONS

Individuals with subclinical hyperthyroidism demonstrate a 41% increase in relative mortality from all causes versus euthyroid control subjects. Mathematical modeling suggests that absolute excess mortality after diagnosis might depend on age, with an increase beyond the age of 60, especially in aging men. For patients with subclinical hypothyroidism, the relative risk of all-cause mortality is increased only in patients with comorbid conditions.

Review: The association of thyroid dysfunction with all-cause and circulatory mortality: is there a causal relationship?

CONTEXT

Currently there is ongoing debate on whether subclinical and overt thyroid dysfunction may exert deleterious effects on the cardiovascular system with the consequence of increased mortality in affected individuals. We systematically review studies on the relation of thyroid dysfunction with all-cause and circulatory mortality questioning whether thyroid dysfunction is a causal factor for mortality.

METHODS

Two investigators independently searched the MEDLINE database. All case-control and cohort studies published in peer-reviewed journals were selected. Studies on nonthyroidal illness or low-T3 syndrome and reports from highly selected populations were not considered. Risk estimates from studies with appropriate adjustment for confounders were metaanalyzed.

RESULTS

Four among eight studies performed to investigate the association between hyperthyroidism and mortality revealed an increased risk of either all-cause or circulatory mortality. Only the minority of studies, however, adjusted analyses for relevant confounders besides age, sex, and race. Studies after radioiodine therapy were generally biased by indication. Findings from 11 studies that investigated the relation between hypothyroidism and mortality were highly discrepant and partly even mutually exclusive. Some of these discrepancies are explained by confounding and selection.

CONCLUSIONS

The currently available evidence for a causal relation of both hyperthyroidism and hypothyroidism with mortality is weak and should particularly not be used to decide whether patients with subclinical thyroid conditions should be treated. Very old individuals might represent an exception from this rule and may benefit from mildly reduced thyroid function, but this has to be substantiated by further research.

Increased cardiovascular and cancer mortality after radioiodine treatment for hyperthyroidism

CONTEXT

Patients treated with radioiodine (RAI) for hyperthyroidism have been reported to be at increased risk for death. It is not clear whether the increased mortality is due to hyperthyroidism itself or the effect of RAI.

OBJECTIVE

Our objective was to compare the mortality of hyperthyroid patients treated with RAI with that of an age- and gender-matched reference population.

DESIGN

We conducted a population-based cohort study.

PARTICIPANTS

A total of 2793 patients who received RAI treatment for hyperthyroidism in Tampere University Hospital between 1965 and 2002, and 2793 reference subjects were followed for a median of 9 yr.

RESULTS

Record linkage with Statistics Finland identified all-cause mortality of 453 vs. 406 per 10,000 person-years in the patients and controls [rate ratio (RR) 1.12; 95% confidence interval 1.03-1.20]. Cerebrovascular diseases accounted for most of the increased mortality among patients (RR 1.40), and mortality from cancer increased (RR 1.29) as well. The risk of death increased in patients older than 60 yr at treatment. Mortality increased with the dose of RAI and was elevated in patients with nodular thyroid disease, but not in those with Graves' disease. Previous treatment with partial thyroidectomy decreased, whereas antithyroid medication did not affect mortality. In Cox regression analysis, RAI-treated hyperthyroidism (RR 1.56) and age (RR 1.10/1 yr) increased, and the development of hypothyroidism (RR 0.52) reduced mortality significantly.

CONCLUSIONS

Hyperthyroidism per se probably accounts for the increased cerebrovascular mortality after RAI treatment. Our results of increased cerebrovascular and cancer mortality emphasize the need for long-term vigilance concerning patients treated with RAI.

Thyroid hormone use, hyperthyroidism and mortality in older women

PURPOSE

Thyroid dysfunction is common, particularly among older women. The safety of thyroid hormone use and long-term prognosis of hyperthyroidism remain controversial. We performed a prospective cohort study to examine the relationship among thyroid hormone use, previous hyperthyroidism, abnormal thyroid function, and mortality.

METHODS

We studied 9449 community-dwelling white women aged > or =65 years followed for 12 years. For analyses of thyroid function, we performed a nested case-cohort in 487 women using a third-generation thyroid-stimulating hormone assay. Causes of death were adjudicated based on death certificates and hospital records.

RESULTS

Twelve percent of the 9449 women took thyroid hormone at baseline, and the mean duration of thyroid hormone use was 15.8 years; 9.4% of participants reported a history of hyperthyroidism. During 12 years of follow-up, 3159 women died (33%). In multivariate analysis, mortality among users of thyroid hormone was similar to that observed for nonusers (relative hazard [RH] 1.11, 95% confidence interval [CI], 0.98-1.24, P=.09). Previous hyperthyroidism was associated with a higher risk of all-cause mortality (RH 1.20, 95% CI, 1.06-1.36), particularly cardiovascular mortality (RH 1.46, 95% CI, 1.20-1.77). Low (< or /=0.5 mU/L) or high (>5 mU/L) thyroid-stimulating hormone levels were not associated with excess total or cause-specific mortality, but the power to detect these relationships was limited.

CONCLUSIONS

Among older women, thyroid hormone use is not associated significantly with excess mortality, but previous hyperthyroidism may be associated with a small increase in all-cause and cardiovascular mortality. Additional long-term studies of hyperthyroidism and its treatment should further explore these findings.

Cardiovascular manifestations of hyperthyroidism before and after antithyroid therapy: a matched case-control study

OBJECTIVES

This study sought to prospectively evaluate the prevalence of cardiovascular abnormalities in patients with overt hyperthyroidism before and after antithyroid therapy.

BACKGROUND

Overt hyperthyroidism is associated with recognized cardiovascular effects believed to be reversed by antithyroid therapy; however, increasing data suggest significant long-term cardiovascular mortality.

METHODS

A total of 393 (312 women, 81 men) consecutive unselected patients with overt hyperthyroidism were recruited and compared with 393 age- and gender-matched euthyroid control subjects. Hyperthyroid patients were re-evaluated after antithyroid therapy. Findings in patients and matched control subjects were compared at presentation, after treatment when patients had subclinical hyperthyroidism biochemically, and when patients were rendered biochemically euthyroid. All had a structured cardiovascular history and examination, including measurements of blood pressure (BP) and pulse rate. All had resting 12-lead electrocardiogram and 24-h digital Holter monitoring of cardiac rhythm.

RESULTS

A higher prevalence of cardiovascular symptoms and signs, as well as abnormal hemodynamic parameters, was noted among hyperthyroid patients at recruitment compared with control subjects. Cardiac dysrhythmias, especially supraventricular, were more prevalent among patients than among control subjects. Palpitation and dyspnea, postural decrease in systolic pressure, and atrial fibrillation (AF) remained more prevalent in treated hyperthyroid subjects with subclinical hyperthyroidism compared with control subjects, and remained more prevalent after restoration of euthyroidism. Predictors for successful reversion to sinus rhythm in those with AF associated with hyperthyroidism were lower BP measurements at recruitment and an initial hypothyroid state induced by antithyroid therapy. Mortality was higher in hyperthyroid subjects than in control subjects after a mean period of follow-up of 66.6 months.

CONCLUSIONS

Cardiovascular abnormalities are common in patients with overt hyperthyroidism at presentation, but some persist despite effective antithyroid therapy.

Mortality and vascular outcomes in patients treated for thyroid dysfunction

CONTEXT

There are limited studies describing mortality and morbidity in patients treated for hyperthyroidism, and no data exist for people with treated hypothyroidism.

OBJECTIVE

The objective of the study was to describe all-cause mortality and vascular mortality and morbidity in patients after treatment for hyperthyroidism and hypothyroidism.

DESIGN

This was a population-based cohort study from 1994 to 2001.

SETTING

The study was conducted in Tayside, Scotland.

PATIENTS

All patients were treated for thyroid dysfunction.

INTERVENTION(S)

Event rates among patients with thyroid dysfunction were compared with rates in the general population. We measured standardized mortality ratio and standardized incidence ratio (SIR).

MAIN OUTCOME MEASURE(S)

The primary outcome was all-cause mortality. The secondary outcome was serious vascular event, the composite end point of nonfatal myocardial infarction, nonfatal stroke, or vascular death.

RESULTS

There were 15,889 primary hypothyroid and 3,888 hyperthyroid patients. There were 3,116,719 patient-years of follow-up in 524,152 subjects in the general population. No increase was found in all-cause mortality or serious vascular events in patients with treated hypothyroidism or hyperthyroidism. Nonfatal ischemic heart disease [SIR 1.23, 95% confidence interval (CI) 1.10-1.36] and dysrhythmias (SIR 1.32, 95% CI 1.11-1.57) were increased in treated hypothyroidism when adjusted for age, sex, diabetic status, and previous vascular disease. In treated stabilized hyperthyroidism, only the risk of dysrhythmias was increased (SIR 2.71, 95% CI 1.63-4.24). Risk of heart failure or cerebrovascular disease was not increased in either patient group.

CONCLUSIONS

We found no increase in all-cause mortality in subjects with treated thyroid disease. However, there was increased risk of cardiovascular morbidity in patients with treated primary hypothyroidism and dysrhythmias in treated hyperthyroidism.

[Subclinical Hyperthyroidism--What is Expected of the General Physician?]

Subclinical hypothyroidism is usually diagnosed during a routine examination. The results of recent studies reveal it to be a significant disease that is associated with a negative impact on myocardial function, an increased incidence of atrial fibrillation in the elderly patient, a loss of bony substance in post-menopausal women, and, possibly, an increased incidence of dementia in the elderly. Associated with this pathology is also a significant increase in the 10-year mortality rate. All this points to an urgent need to determine the underlying cause of sub-clinical hypothyroidism and to treat the condition in thesame way as manifest hyperthyroidism.

[Uncertainties about the benefit of treatment in subclinical thyroid dysfunction]

The Leiden 85-plus study in the oldest old has observed (a) no relationship between thyroid function and symptoms of depression, cognitive impairment or disabilities in daily life, and (b) increased mortality in subjects with TSH < 0.3 mU/l as well as longer survival in subjects with TSH > 4.8 mU/l. Subclinical hyperthyroidism probably warrants more proactive treatment as other studies have also shown increased mortality to accompany a low TSH, although no randomised trials have been done to prove that early intervention prevents atrial fibrillation or prolongs life. The benefits of treatment for subclinical hypothyroidism at a very advanced age are uncertain, but treatment might well be beneficial in middle-aged subjects as some studies report an increased risk of cardiovascular morbidity and mortality. In all cases, however, it is recommended that underlying thyroid disease be demonstrated before treatment is started.

Influence of thyroid disorders on kidney angiotensinase activity

Thyroid disorders affect renal function, which involves changes in local renin angiotensin system (RAS). Angiotensin peptide levels in the tissue are regulated by the activity of several aminopeptidases (AP) known as angiotensinases. The nature and consequences of the thyroid-induced RAS changes are not completely understood. We investigated the relationship between thyroid status (hyper- and hypothyroidism) and several kidney AP actions involved in RAS control. We have determined fluorometrically soluble (SOL) and membrane-bound (M-B) alanylaminopeptidase (AlaAP), glutamylaminopeptidase (GluAP) and aspartylaminopeptidase (AspAP) activity using naphthylamide derivatives as substrates. Sprague-Dawley rats were divided into three groups--control, hyperthyroid, and hypothyroid. Hyperthyroidism was induced by daily subcutaneous injection of L-thyroxin (300 microg/kg/day). Hypothyroidism was induced by continuous administration of methimazole (0.03%) in drinking water. Hypothyroid animals demonstrated a significant increase in SOL and M-B GluAP activity in renal cortex and a decrease in M-B AlaAP compared to euthyroid rats. This result may suggest higher Ang III availability. In hyperthyroid animals, M-B AlaAP and M-B AspAP activity increased significantly, which may suggest increased Ang III to Ang IV metabolism and greater formation of Ang 2-10, respectively. In contrast, no differences were observed between euthyroid and hypothyroid animals for SOL and M-B AP activity in renal medulla. However, hyperthyroid animals demonstrated a significant decrease in SOL and M-B GluAP activity compared to euthyroid rats, which may suggest a greater availability of Ang II in renal medulla. Alterations in angiotensin metabolism may, in part, account for some changes in renal function during thyroid disorders.

Thyroid hormone concentrations, disease, physical function, and mortality in elderly men

CONTEXT

Physiological changes in thyroid hormone concentrations might be related to changes in the overall physical function in the elderly.

OBJECTIVE

We determined to what extent thyroid hormone concentrations are related to physical function and mortality in elderly men.

DESIGN

A longitudinal population study (the Zoetermeer study) was conducted. Mortality was registered in the subsequent 4 yr.

PARTICIPANTS

Four hundred three independently and ambulatory living men (aged 73-94 yr) participated.

MAIN OUTCOME MEASURES

The study examined the association between serum thyroid hormones and parameters of physical function as well as the association with mortality.

METHODS

TSH, free T4 (FT4) total T4, T3, rT3, and T4-binding globulin were measured. Physical function was estimated by the number of problems in activities of daily living, a measure of physical performance score (PPS), leg extensor strength and grip strength, bone density, and body composition.

RESULTS

Serum rT3 increased significantly with age and the presence of disease. Sixty-three men met the biochemical criteria for the low T3 syndrome (decreased serum T3 and increased serum rT3). This was associated with a lower PPS, independent of disease. Furthermore, higher serum FT4 (within the normal range of healthy adults) and rT3 (above the normal range of healthy adults) were related with a lower grip strength and PPS, independent of age and disease. Isolated low T3 was associated with a better PPS and a higher lean body mass. Low FT4 was related to a decreased risk of 4-yr mortality.

CONCLUSIONS

In a population of independently living elderly men, higher FT4 and rT3 concentrations are associated with a lower physical function. High serum rT3 may result from a decreased peripheral metabolism of thyroid hormones due to the aging process itself and/or disease and may reflect a catabolic state. Low serum FT4 is associated with a better 4-yr survival; this may reflect an adaptive mechanism to prevent excessive catabolism.

Thyroid function and mortality in patients treated for hyperthyroidism

CONTEXT

Hyperthyroidism has been reported to cause excess all-cause and circulatory mortality. Whether this can be reversed is unknown, as is the influence of mild persisting thyroid dysfunction and treatment-induced hypothyroidism.

OBJECTIVES

To determine whether radioiodine treatment is associated with increased mortality and to determine the influences of mild thyroid dysfunction and the development of overt hypothyroidism treated with thyroxine (T(4)).

DESIGN, SETTING, AND PARTICIPANTS

A population-based study of 2668 individuals aged 40 years or older treated for overt hyperthyroidism with radioiodine in the West Midlands region of England from 1984-2002.

MAIN OUTCOME MEASURES

Cause of death compared with age- and period-specific mortality in England and Wales and assessment of the influence of T(4) therapy for radioiodine-induced hypothyroidism and subclinical thyroid dysfunction on mortality.

RESULTS

In 15,968 person-years of follow-up, 554 died vs 487 expected deaths (standardized mortality ratio [SMR], 1.14; 95% confidence interval [CI], 1.04-1.24, P=.002). Increased risks of all-cause and circulatory deaths vs age- and period-specific mortality were observed in follow-up in those not requiring, or prior to, T(4) therapy. These increased risks were not observed during follow-up on T(4) therapy (circulatory disease SMR prior to T(4), 1.33; 95% CI, 1.14-1.53 vs SMR, 0.91; 95% CI, 0.70-1.17 during T(4)). Patients receiving T(4) had decreased risk of mortality vs risk in the period not requiring, or prior to, T(4) therapy (all-cause mortality hazard ratio [HR], 0.65; 95% CI, 0.54-0.79; circulatory mortality HR, 0.65; 95% CI, 0.48-0.87). Increased all-cause mortality vs the background population was observed in the period prior to T(4) therapy in follow-up associated with low, normal, and high serum thyrotropin. The SMR for ischemic heart disease increased slightly when analyzed by serum thyrotropin, high serum thyrotropin being the highest SMR (low thyrotropin SMR, 1.06; 95% CI, 0.75-1.45; normal thyrotropin SMR, 1.17; 95% CI, 0.76-1.71; high thyrotropin SMR, 1.48; 95% CI, 0.86-2.37). Comparison within the cohort showed that mild hypothyroidism prior to T(4) therapy was associated with increased risk of mortality from ischemic heart disease vs biochemical euthyroidism (HR, 2.08; 95% CI, 1.04-4.19).

CONCLUSIONS

Patients treated with radioiodine for hyperthyroidism had increased mortality vs age- and period-specific mortality in England and Wales, a finding no longer evident during T(4) therapy. This supports treating hyperthyroidism with doses of radioiodine sufficient to induce overt hypothyroidism. The association within the cohort of mortality from ischemic heart disease with subclinical hypothyroidism suggests T(4) replacement should be considered should this biochemical abnormality develop after radioiodine therapy.

[Diminished TSH level--an incidental finding]

Too-low a TSH level detected fortuitously during a routine examination should raise the suspicion of subclinical hyperthyroidism. The question as to whether treatment is required largely depends on the age of the patient and on his general state of health. If considered necessary, treatment is oriented to the guidelines for the treatment of hyperthyroidism.

Mortality rate of chronically ill geriatric patients with subnormal serum thyrotropin concentration: a 2-yr follow-up study

We investigated the natural course of subclinical thyroid dysfunctions in geriatric patients, especially regarding their association with mortality rate. Ninety-three randomly selected chronically ill geriatric patients 64- 87 (median: 77) yr of age participated in the screening study with a 2-yr follow-up. Serum thyrotropin (thyroid- stimulating hormone [TSH]), free thyroxine, triiodothyronine, and antibodies against thyroid peroxidase were measured. During the follow-up, patients with suppressed TSH levels who were otherwise euthyroid (untreated) had a higher mortality rate than patients with normal TSH (5/8 vs 18/64; p < 0.05). The initial clinical state of these two subgroups did not differ significantly. Two-thirds of patients with treated hyperthyroidism died. The mortality rate of patients with initially subnormal but not suppressed TSH level was average and did not differ statistically from either the euthyroid or the hyperthyroid groups. Only 1 of 13 euthyroid patients with positive thyroid antibody titers developed a subsequent subclinical hypothyroidism. Subclinical hyperthyroidism was found to be associated with a higher mortality rate in chronically ill geriatric patients, which justifies screening for thyroid dysfunction and treatment of subclinical hyperthyroidism. In addition, a subnormal but measurable TSH was not indicative regarding the future development of hyperthyroidism. Finally, during the 2-yr follow-up, antibody positivity in the euthyroid cases did not prove to be predictive for the subsequent development of hypothyroidism.

Current treatment of nodular goiter with hyperthyroidism (Plummer's disease): surgery versus radioiodine

BACKGROUND

First described 9 decades ago by H. S. Plummer, thyroidectomy and radioiodine remain the 2 therapeutic modalities for toxic nodular goiter. The aim of this study was to determine its optimal treatment.

METHODS

The presentation, operative treatment, pathology, and clinical course of 362 consecutive patients treated at our institution for Plummer's disease from 1990 to 1999 were retrospectively reviewed.

RESULTS

Three hundred forty-six patients (63 men and 283 women) were treated surgically (181, 53%), with radioiodine (RAI, 157, 45%), or a combination of both (8, 2%). Mean age was 62 years (surgical, 55 years; RAI, 69 years). Nearly half were symptomatic, 51 (15%) with airway or swallowing compromise and 110 (32%) with cardiac complications. The estimated goiter size was larger (60 g or greater) in surgical (72 patients, 38%) than medically treated (45 patients, 29%) patients. RAI treatment dose averaged 28 mCi; 10 patients (6%) required a second treatment, and 8 patients failed treatment and required subsequent thyroidectomy. Types of thyroidectomy included total (29 patients, 16%), near-total (47 patients, 26%), bilateral subtotal (46 patients, 25%), and unilateral (58 patients, 32%). One month after treatment, hyperthyroidism had resolved in 96% of the surgical patients but only 6% of the RAI patients (mean time to resolution, 5.4 months). Only 55 (38%) of the RAI patients' goiters reduced in size. Recurrent laryngeal nerve paralysis and hypoparathyroidism each occurred in 3 (2%) patients.

CONCLUSIONS

Surgical treatment results in rapid, reliable resolution of hyperthyroidism and removal of the nodular goiter with low morbidity and no mortality. RAI is also safe and effective, usually requiring a single dose, but the results are delayed and it usually fails to resolve a goiter.

Hyperthyroidism and cardiovascular morbidity and mortality

Hyperthyroidism is a common disorder affecting multiple systems in the body. The cardiovascular effects are among the most striking. The availability of effective treatments for hyperthyroidism has led to the widespread perception that it is a reversible disorder without any long-term consequences. Recent evidence suggests, however, that there may be adverse outcomes. Long-term follow-up studies have revealed increased mortality from cardiovascular and cerebrovascular disease in those with a past history of overt hyperthyroidism treated with radioiodine, as well as those with subclinical hyperthyroidism. Thyroid hormones are known to exert direct effects on the myocardium, as well as the systemic vasculature and predispose to dysrhythmias, especially supraventricular. Atrial fibrillation (AF) is a recognized complication of overt hyperthyroidism, and subclinical hyperthyroidism is also known to be a risk factor for development of AF. Supraventricular dysrhythmias, particularly atrial fibrillation, in older patients may account for some of the excess cardiovascular and cerebrovascular mortality described, especially because AF is known to predispose to embolic phenomena.

Influences of early thyroid hormone manipulations: delays in pup motor and exploratory behavior are evident in adult operant performance

The effects of thyroid hormone depletion and enhancement on litter size, survival, body mass, ambulation, quadrant crossing, home orientation, day of eye opening, and free serum T3 and T4 levels were examined in Study 1. In Study 2, the effects of the timing of prenatal insult and the level of thyroid hormone depletion on litter size, survival, body mass, and free serum T3 and T4 levels were examined. Upon the completion of Study 1, randomly selected pups were maintained on ad-libitum water and food for 2 years, and performance was evaluated on fixed and variable ratio schedules, fixed and variable interval schedules, and probability and reversal learning tasks (Study 3). In Study 4, human subjects diagnosed with and treated for either congenital hypothyroidism or congenital hyperthyroidism were tested on the operant procedures used in Study 3, as well as on a series of simple reaction time, serial timing, and conjunctive and disjunctive search tasks. Dose-dependent decreases in survival and delays in the presentation of early motor and exploratory skills were observed following thyroid hormone depletion; dose-dependent accelerations in the presentation of early motor and exploratory skills were observed following thyroid hormone enhancement. Pups that had been prenatally exposed to propylthiouracil (PTU) 1-2 years after the return of thyroid hormones to baseline levels were significantly less accurate at timing on fixed and variable interval schedules, demonstrated an inability to allocate responding on probability tasks, and committed more errors during original learning (OL) and on each reversal problem. Similar deficits were observed in follow-up tests with humans diagnosed with congenital hypothyroidism, as were deficits in serial timing and visual searching. Collectively, the present results demonstrate that the pervasive and negative effects of prenatal thyroid deficiency on early behavior are also expressed during adult operant performance.