Ethnic differences in patients undergoing thyroidectomy for non-toxic multinodular goitre.

BACKGROUND: Maori have an increased incidence of thyrotoxicosis when compvared to non-Maori, however there are limited data on benign non-toxic nodular thyroid disease. AIMS: The aims of this study were to determine the rates of non-toxic multinodular goitre (NTMNG) surgery for Maori and non-Maori and to determine if there were differences in thyroid size between Maori and non-Maori undergoing total thyroidectomy for NTMNG. METHODS: Single centre study of patients undergoing thyroidectomy for NTMNG from 1 December 2006 to 30 November 2016. RESULTS: Maori were overrepresented amongst the 427 patients who underwent surgery for NTMNG at 34% compared to the expected ~17% of the background Maori adult population in the region. At the time of surgery, Maori were younger (P = 0.004) and had a larger thyroid gland (P < 0.001) when compared to non-Maori also undergoing total/near total thyroidectomy. Complication rates were low across all ethnic groups. CONCLUSION: Maori have increased rates of surgery for NTMNG compared to non-Maori and thyroid size is larger at the time of surgery. The reasons for this are currently unknown and more research is required.

Glycaemic control across the lifespan in a cohort of New Zealand patients with type 1 diabetes mellitus.

BACKGROUND: It is well known that tight glycaemic control reduces all-cause mortality and the development of microvascular complications in patients with type 1 diabetes mellitus (T1D), but that effective glycaemic control is difficult to achieve in different age groups. Currently, the state of glycaemic control across the lifespan in patients with T1D in New Zealand is not known. AIM: To determine the differences in glycaemic control with age, gender, rurality and ethnicity in patients with T1D in the Waikato region of New Zealand. METHODS: Retrospective review of clinical records of all patients with T1D on the Waikato Regional Diabetes Database in December 2017 (n = 1303). Glycaemic control was determined by the most recent HbA1c in the past 2 years. RESULTS: Median (25%, 75%) HbA1c was 67 (59, 81) mmol/mol (8.3%) and highest in those aged 15-29 years. Values exceeded clinical recommendations in 85.3% of all patients. Median HbA1c was lower in patients on insulin pump therapy than on multiple daily injections (63 (7.9%) versus 69 mmol/mol (8.5%); P < 0.001), though insulin pumps were significantly less likely to be used by Maori (P = 0.003) and men (P < 0.0001). Worsening glycaemic control was associated with increasing social deprivation (P < 0.001) but was not influenced by rural/urban living. CONCLUSIONS: Poor glycaemic control in Waikato patients with T1D is likely due to inequities in health care, including reduced access to insulin pump therapy, particularly in Maori and socially deprived populations.

Thyrotoxicosis in an Indigenous New Zealand Population - a Prospective Observational Study.

BACKGROUND: Reported international incidence rates of thyrotoxicosis vary markedly, ranging from 6 to 93 cases per 100 000 per annum. Along with population demographics, exposures, and study design factors, ethnicity is increasingly being recognized as a potential factor influencing incidence. This study aimed to document the epidemiology and clinical presentation of thyrotoxicosis for Maori, the indigenous population in New Zealand. METHODS: A prospective study of adult patients presenting with a first diagnosis of thyrotoxicosis between January 2013 and October 2014 to a single New Zealand center. Demographic data were collected, and detailed clinical assessment performed. RESULTS: With 375 patients, an incidence rate of thyrotoxicosis of 73.0 per 100 000 per annum was identified. Of these, 353 (94.1%) participated in the study. The median age of the cohort was 47 years, 81% were female, and 58% had Graves disease. The overall incidence of thyrotoxicosis for Maori, the indigenous people of New Zealand, was higher than non-Maori (123.9 vs 57.3 per 100 000 per annum). Rates of both Graves disease and toxic multinodular goiter were higher in Maori as compared to non-Maori (incidence rate ratios of 1.9 [1.4, 2.6] and 5.3 [3.4, 8.3], respectively), with this increase being maintained after controlling for age, deprivation, and smoking. CONCLUSIONS: Maori, the indigenous people of New Zealand, have an increased incidence of thyrotoxicosis compared to non-Maori and, in particular, toxic multinodular goiter. A greater understanding of the epidemiology of thyrotoxicosis in other indigenous and marginalized ethnic groups may help to optimize therapeutic pathways, equitable care and outcomes.

Inequitable Long-Term Outcomes for an Indigenous Population After Definitive Treatment of Patients With Graves Disease.

BACKGROUND: Maori, the indigenous people of Aotearoa/New Zealand, have an increased incidence of Graves disease and often require more than one radioiodine (RAI) dose, raising the question as to whether surgery may be preferable in this population. However, there is a lack of outcome data after definitive therapy in an indigenous population. AIM: To assess ethnic differences in thyroid status after definitive therapy for Graves disease. METHODS: Single-center retrospective review of patients treated by RAI or thyroidectomy from 1 December 2001 to 31 March 2013. TSH levels at 1, 2, 5, and 10 years after treatment were recorded. RESULTS: A total of 798 patients were included: 589 received RAI, and 209 underwent surgery. Overall, 48% of patients were euthyroid at 1 year after definitive treatment, and 63.5% were euthyroid by 10 years. Maori were less likely to be euthyroid when compared with Europeans at all time points (e.g., 29.7% vs 57.3% at 1 year and 52.2% vs 70.9% at 10 years, P < 0.0005). Maori were more likely to receive more than one dose of RAI compared with Europeans (30.2% vs 14.2%, P < 0.0005). Persistent thyrotoxicosis at 1 year after RAI was seen in 25.8% of Maori compared with 8.3% of Europeans (P < 0.0005). CONCLUSIONS: Maori have lower rates of optimal thyroid levels than their European counterparts at all time points studied. Early disparity was associated with a higher RAI failure rate. Late differences were due to higher rates of untreated hypothyroidism. Overall, euthyroid rates were low, indicating the need for improvement in care, particularly for indigenous peoples.

Increased Admissions Due to Cardiac Complications of Thyrotoxicosis in Maori.

BACKGROUND: As thyrotoxicosis is a risk factor for atrial fibrillation, current guidelines recommend measuring a thyroid-stimulating hormone level in patients with this disorder. Hyperthyroidism may also be associated with other heart diseases including cardiac ischaemia and cardiac failure. Currently, the prevalence of thyrotoxicosis in cardiac admissions in the absence of a rhythm disorder is unknown. AIMS: The aims of this study were: 1) to calculate the prevalence of admissions for thyrotoxicosis-associated cardiac disease, 2) determine the type of cardiac disease i.e. dysrhythmic, ischaemic or cardiac failure, and 3) to assess whether Maori are over-represented amongst patients admitted to hospital with cardiac complications of thyrotoxicosis. METHODS: A retrospective review of admissions with both thyrotoxicosis and cardiac disease from 1 January 2005 to 31 December 2012 inclusive. RESULTS: Seventy-two patients were identified as being admitted for a cardiac complication of thyrotoxicosis, giving a mean of nine admissions per year. Dysrhythmia was the cause for admission in 32 patients, ischaemia in 12, cardiac failure in 11 and mixed cardiac disease in 17. Graves' disease and amiodarone-induced were the most common causes of the thyrotoxicosis (25 and 19 cases, respectively). Of the cohort 26 (36.1%) were Maori (compared to 16.8% of all cardiac admissions over the same period). Maori were more likely to present with cardiac failure than non-Maori (57.7% vs. 26.1%, p=0.008 respectively). CONCLUSIONS: Maori are over-represented amongst patients admitted with cardiac complications of thyrotoxicosis and more often present with cardiac failure than non-Maori. Measurement of thyroid function should be considered in patients presenting not only with atrial fibrillation but also in patients presenting with cardiac failure, particularly if they are Maori.

Treatment choice, satisfaction and quality of life in patients with Graves' disease.

BACKGROUND: Thyrotoxicosis, most often caused by Graves' disease (GD), when treated inadequately may result in premature mortality. There is little consensus as to which of the 3 treatment options available - antithyroid drugs (ATD), radioactive iodine (RAI) and surgery, is better. AIMS: (i) To assess factors involved in treatment choice and treatment satisfaction in patients treated for Graves' disease; (ii) To assess quality of life (QoL) following treatment of Graves' disease. METHOD: Participants were selected from a prospective study cohort assessing thyrotoxicosis incidence and severity. Of the 172 eligible patients with Graves' disease, 123 treated patients participated (64% had received ATD only, 11% RAI and 25% total thyroidectomy, the latter 2 usually after a period of ATD), along with 18 untreated patients with newly diagnosed Graves' disease (overall participation rate, 73%). Consented patients completed a questionnaire detailing factors involved in treatment choice, QoL and satisfaction with treatment. RESULTS: Participants reported that the most important factors in choosing a treatment were the following: the effects on activities of daily living, concern about use of radioiodine, possibility of depression or anxiety, and doctor's recommendations. Satisfaction levels were high across all 3 treatment types. QoL 1-year following treatment was higher than in untreated patients, and comparable with other international studies. CONCLUSIONS: Patient satisfaction with therapy and QoL does not differ by treatment type. Therefore, clinical and social factors, in combination with patient choice and resource availability, should determine which treatment modality patients with Graves' disease should receive.

Response to Radioiodine Therapy for Thyrotoxicosis: Disparate Outcomes for an Indigenous Population.

Despite 70 years of experience treating thyrotoxic patients with radioiodine not all patients are successfully treated by a single dose. Multiple factors predicting radioiodine efficacy have been reported. The aim of this study was to assess whether ethnicity was associated with radioiodine response. A retrospective review was performed of patients who received radioiodine therapy for thyrotoxicosis from 1 January 2008 to 31 December 2010 and had follow-up available of a minimum of 12 months. 224 patients were included, 82.4% female, and 63.7% had Graves's disease. Radioiodine failed in 21.5% of patients overall, with a higher failure rate in the indigenous population (35.2%). When controlling for other influencing factors by logistic regression, there continued to be an increased risk for the indigenous group (OR 2.82) and those treated with antithyroid drugs following radioiodine (OR 2.04). Younger age was also associated with an increased risk of failing radioiodine therapy (OR 0.97 for each year of age). Cure rates following radioiodine were lower for indigenes independent of factors known to affect radioiodine outcome. This is the first report demonstrating ethnicity as a possible independent variable for radioiodine efficacy. Further work is needed to investigate the cause of this difference.

A low incidence of iodine-induced hyperthyroidism following administration of iodinated contrast in an iodine-deficient region.

OBJECTIVE: There are limited data on the incidence of iodinated contrast-induced thyrotoxicosis, particularly in iodine-deficient regions. The aim of this study was to determine the incidence of iodinated contrast-induced thyrotoxicosis and to determine whether thyrotoxicosis was more common in patients ≥70 years compared to those <70 years of age. DESIGN: A prospective study of adult patients undergoing an outpatient CT with iodinated contrast was performed. MEASUREMENTS: Thyroid function tests (TFTs) and urine iodine measurements were performed prior to the scan. TFTs were repeated at 4- and 8-weeks postscan. Changes in TFTs from baseline were analysed. RESULTS: A total of 102 patients were included in the final analysis. Overall, TSH levels dropped (P = 0·0002), and free T3 (FT3 ) levels increased (P = 0·04) between baseline and week 4 with normalization by week 8; however, these changes were not considered clinically significant. No significant differences in free T4 (FT4 ) occurred in the overall group (P = 0·82). There were no differences in TFTs between baseline and 4 or 8 weeks for those patients aged <70 compared to ≥70 years. Two patients developed new subnormal TSH values. Of these, one had a 90-mm follicular variant papillary thyroid carcinoma diagnosed while the other had a normal thyroid assessment and TSH spontaneously normalized by 12 weeks. CONCLUSIONS: Only 2% of patients developed subclinical hyperthyroidism following a standard dose of iodinated contrast for CT investigations. Given the low incidence of iodine-induced thyrotoxicosis, there is no indication for routine pre- and post-CT thyroid function testing in our region.

Pregnancy after definitive treatment for Graves' disease--does treatment choice influence outcome?

BACKGROUND: Women requiring thyroid hormone replacement after definitive therapy (surgery or radioiodine) for Graves' disease who later conceive require an early increase in levothyroxine dose and monitoring of thyroid hormone levels throughout pregnancy. In addition, as TSH receptor antibodies (TRAb) can cross the placenta and affect the fetus, measurement of these antibodies during pregnancy is recommended. AIM: To review the management of pregnancies following definitive treatment for Graves' disease in order to assess the rates of maternal hypothyroidism and TRAb measurement. MATERIALS AND METHODS: Retrospective chart review of women who had undergone definitive treatment for Graves' disease at a tertiary hospital and subsequently had one or more pregnancies. RESULTS: A total of 29 women were identified, each of whom had at least one pregnancy since receiving definitive treatment for Graves' disease: there were a total of 49 pregnancies (22 in the surgical group and 27 in the radioiodine group). Both groups had high rates of hypothyroidism documented during pregnancy (47 and 50%, respectively). The surgical group was more likely to be euthyroid around the time of conception. Less than half of the women were referred to an endocrinologist or had TRAb measured during pregnancy. Neonatal thyroid function was measured in one-third of live births. One case of neonatal thyrotoxicosis was identified. CONCLUSIONS: Adherence to the current American Thyroid Association guidelines is poor. Further education of both patients and clinicians is important to ensure that treatment of women during pregnancy after definitive treatment follows the currently available guidelines.

Thyroid cancer in Graves' disease: is surgery the best treatment for Graves' disease?

BACKGROUND: Graves' disease is a common cause of thyrotoxicosis. Treatment options include anti-thyroid medications or definitive therapy: thyroidectomy or radioactive iodine (I(131) ). Traditionally, I(131) has been the preferred definitive treatment for Graves' disease in New Zealand. Reports of concomitant thyroid cancer occurring in up to 17% of Graves' patients suggest surgery, if performed with low morbidity, may be the preferred option. The aim of this study was to determine the rate of thyroid cancer and surgical outcomes in a New Zealand cohort of patients undergoing thyroidectomy for Graves' disease. METHOD: This study is a retrospective review of Waikato region patients undergoing thyroid surgery for Graves' disease during the 10-year period prior to 1 December 2011. RESULTS: A total of 833 patients underwent thyroid surgery. Of these, 117 were for Graves' disease. Total thyroidectomy was performed in 82, near-total in 33 and subtotal in 2 patients. Recurrent thyrotoxicosis developed in one subtotal patient requiring I(131) therapy. There were two cases of permanent hypoparathyroidism and one of permanent recurrent laryngeal nerve palsy. Eight patients (6.8%) had thyroid cancer detected, none of whom had overt nodal disease. Five were papillary microcarcinomas (one of which was multifocal), two were papillary carcinomas (11 mm and 15 mm) and one was a minimally invasive follicular carcinoma. CONCLUSION: Thyroid cancer was identified in approximately 7% of patients undergoing surgery for Graves' disease. A low complication rate (<2%) of permanent hypoparathyroidism and nerve injury (<1%) supports surgery being a safe alternative to I(131) especially for patients with young children, ophthalmopathy or compressive symptoms.