Trends and Regional Variation in Rates of Thyroidectomy in Australia

Thyroid disease incidence has increased over the last three decades, but mortality has been stable. Our study assessed the trends and geographical variation in thyroid procedures across Australia over a 10-year period which spanned the introduction of the American Thyroid Association (ATA) Guidelines in 2015 and therefore aimed to capture any resulting changes in practice, as well as other factors influencing geographic variability.

Medicare Benefits Scheme (MBS) data was extracted for items 30296 (Total Thyroidectomy), 30306 (Hemithyroidectomy), and 30310 (Partial Thyroidectomy) between January 2014 and December 2023. We calculated absolute and relative per capita frequencies for Total and Partial Thyroidectomy subgroups and assessed trends over time, as well as geographic variability.

The total number of thyroid procedures performed per year did not increase significantly over the study period (5824 in 2014 vs. 6434 in 2023, p > 0.05); however, the number of Partial Thyroidectomies significantly increased (2899 in 2014 vs. 3934 in 2023, p < 0.01), and Total Thyroidectomies significantly decreased (2925 in 2014 vs. 2500 in 2023, p < 0.01). The per-capita state-based rate for all thyroidectomy procedures varied by 300% (93 procedures-per-capita in NT vs. 279 procedures-per-capita in NSW).

The rate of change in different thyroid procedures over time in our study and our findings of lower geographical variation compared to studies conducted prior to 2015 suggest that ATA Guidelines may have reduced the contribution of physician-related factors to geographic variability and de-escalated the extent of procedures for patients with low-risk pathology. Geographic variation is, however, multifactorial, and these findings also likely reflect other factors like socioeconomic status and access to healthcare.