Effectiveness and cost-effectiveness of thyroidectomy in the management of Graves' disease in Hong Kong

Abstract

With rising medical costs and the high prevalence of Graves' disease (GD) in the general population, a safe and effective treatment for GD is needed. Antithyroid drugs (ATD), radioactive iodine (RAI), and thyroidectomy have all been proven to be safe and effective. This thesis aimed to compare the clinical effectiveness and cost-effectiveness of thyroidectomy with those in other two treatment options.

This thesis comprised six parts. First, a systematic review and network meta-analysis, including 31 studies and 135,905 patients, was performed to compare the effects of thyroidectomy, ATD, and RAI therapy. Second, a population-based retrospective cohort study was conducted to evaluate the 10-year effectiveness of surgery versus non-surgical treatments as first-line treatments for 6,385 patients with newly diagnosed GD (327 with surgery, 4,784 with ATD, and 1,274 with RAI). Third, another study conducted among 3,443 patients with relapsed GD (394 with surgery, 2294 with ATD, and 755 with RAI) calculated the healthcare costs and compared the effectiveness of treatments on cardiovascular diseases (CVD), atrial fibrillation (AF), psychological diseases, Graves' ophthalmopathy (GO), and cancer. Fourth, the association was evaluated between early good control of thyroid hormone levels after surgery and subsequent risks of mortality and morbidity among patients following total thyroidectomy. Fifth, a prospective cohort study was performed to estimate the health-related quality of life (HRQoL) and utility score of 125 relapsed GD patients from baseline to 12 months. Lastly, a cost-effectiveness analysis of thyroidectomy versus non-surgical treatments was evaluated over 10 years.

The network meta-analysis indicated that thyroidectomy was associated with lower risks of mortality and GO than ATD and RAI. Results from the retrospective cohort study showed that thyroidectomy as first-line treatment had significantly lower risks than ATD and RAI in all-cause mortality [hazard ratio (HR) = 0.33, 0.45], CVD (HR =0.13, 0.20), AF (HR =0.23, 0.44), psychological disease (HR =0.35, 0.43), diabetes (HR =0.11, 0.12), hypertension (HR =0.63, 0.51), GO (HR =0.78, 0.81), and cancer (HR =0.75, 0.89). Among patients with relapsed GD, surgery was associated with lower risks of all-cause mortality (HR =0.40, 0.38), CVD (HR =0.54, 0.52), AF (HR =0.11, 0.26), psychological disease (HR =0.85, 0.64), GO (HR =0.09, 0.07), and cancer (HR =0.56, 0.59) compared with ATD and RAI. The 10-year cumulative healthcare cost of the surgery was relatively lower than ATD and RAI. In addition, patients in hypothyroidism group had a significantly higher risk of CVD than those who achieved euthyroidism early after thyroidectomy (HR = 4.20), while hyperthyroidism group had a higher risk of cancer (HR = 2.14). Moreover, significant improvements in HRQoL were observed among all patients after treatments for relapsed GD. Regarding the 10-year cost-effectiveness, patients undergoing thyroidectomy as first-line or second-line treatment were predicted to have a lower medical cost and improved quality adjusted life years than those treated with ATD and RAI.

Along with the lower risks of morbidities and mortality, thyroidectomy incurred lower healthcare costs. Over the medium term, thyroidectomy appeared to be cost-saving than other treatment modalities like ATD or RAI for patients suffering from GD.