Table 1_Cross-sectional analysis of 152 hyperthyroid cats presented for radioactive iodine therapy in South Korea.xlsx

Human-licensed or generic methimazole was used more frequently than veterinary-licensed methimazole (84.0 vs. 18.1%). Pruritus occurred more frequently with human-licensed or generic methimazole than with veterinary-licensed methimazole (p = 0.047). All cats were housed indoors.

The regional distribution of cases differed from the reported national distribution of owned cats (p = 0.016). No cats originated from Jeju-do, which differed significantly from the mainland regions (p = 0.0004). Longer disease duration was associated with more advanced disease, including higher thyroid hormone levels and scintigraphic activity, increased bilateral involvement, and a higher rate of refractory response to antithyroid drugs (all p ≤ 0.001).</p>Conclusions<p>This is the first study to characterize cats with hyperthyroidism that were presented for RAIT in South Korea.

Key findings included an owner-driven pattern of RAIT selection, early use of definitive therapy despite a relatively late diagnosis, predominant use of non-veterinary methimazole formulations, and a higher frequency of pruritus as an adverse effect. These findings contribute to the epidemiological understanding of feline hyperthyroidism and may inform clinical decision-making in South Korea.</p>