Cox Sarah E, Wakeling Jennifer, Hall Teresa, Williams Tim L
Department of Veterinary Medicine, University of Cambridge, Cambridge, UK.
Douglas College, Coquitlam, British Columbia, Canada.
J Vet Intern Med. 2025 Jan-Feb;39(1):e17295. doi: 10.1111/jvim.17295.
Hyperthyroid cats that are azotemic and hypothyroid after surgical or medical treatment have poor outcomes, and supplementation with levothyroxine (LT4) improves survival. However, the effect of LT4 supplementation on survival of nonazotemic, hypothyroid radioiodine (RI)-treated hyperthyroid cats is unknown.
Radioiodine treated hyperthyroid cats with iatrogenic hypothyroidism or azotemia have shorter survival times than euthyroid, nonazotemic cats and supplementation of LT4 improves survival times of hypothyroid cats.
One hundred seventeen RI treated hyperthyroid cats.
Prospective cohort study. Radioiodine treated cats were screened for azotemia and iatrogenic hypothyroidism using TSH stimulation test; LT4 supplementation was offered to all hypothyroid cats with decision to treat based on owner preference. The log rank test was used to compare survival times between groups, and the Mann-Whitney U test was used to compare age and renal variables. Data are presented as median [range].
Euthyroid azotemic cats (934 [759-2035] days) and nonsupplemented hypothyroid cats (azotemic and nonazotemic combined, 1232 [238-2363] days) had shorter survival times than euthyroid nonazotemic cats (1616 [663-3369] days, P = .003 and P = .002, respectively). Levothyroxine supplemented hypothyroid nonazotemic cats had longer survival times than nonsupplemented hypothyroid nonazotemic cats (1037 [300-2401] days vs 768 [34-1014] days; P = .027). Levothyroxine supplementation was not associated with prolonged survival times in hypothyroid azotemic cats vs nonsupplemented hypothyroid azotemic cats (771 [718-1558] days vs 152 [82-1852] days, respectively, P = .991).
Levothyroxine supplementation in nonazotemic cats with iatrogenic hypothyroidism (diagnosed based on TSH stimulation test results) improved survival times, although randomized controlled trials are needed.
接受手术或药物治疗后出现氮血症和甲状腺功能减退的甲状腺功能亢进猫预后较差，补充左甲状腺素（LT4）可提高生存率。然而，补充LT4对非氮血症、甲状腺功能减退的放射性碘（RI）治疗的甲状腺功能亢进猫生存率的影响尚不清楚。
接受放射性碘治疗的医源性甲状腺功能减退或氮血症的甲状腺功能亢进猫的生存时间比甲状腺功能正常、非氮血症的猫短，补充LT4可提高甲状腺功能减退猫的生存时间。
117只接受RI治疗的甲状腺功能亢进猫。
前瞻性队列研究。使用促甲状腺激素刺激试验对接受放射性碘治疗的猫进行氮血症和医源性甲状腺功能减退筛查；向所有甲状腺功能减退的猫提供LT4补充剂，并根据主人的偏好决定是否治疗。采用对数秩检验比较各组之间的生存时间，采用曼-惠特尼U检验比较年龄和肾脏变量。数据以中位数[范围]表示。
甲状腺功能正常的氮血症猫（934[759-2035]天）和未补充LT4的甲状腺功能减退猫（氮血症和非氮血症合并，1232[238-2363]天）的生存时间比甲状腺功能正常的非氮血症猫（1616[663-3369]天）短，分别为P = 0.003和P = 0.002）。补充左甲状腺素的甲状腺功能减退非氮血症猫的生存时间比未补充的甲状腺功能减退非氮血症猫长（1037[300-2401]天对768[34-1014]天；P = 0.027）。与未补充LT4的甲状腺功能减退氮血症猫相比，补充左甲状腺素对甲状腺功能减退氮血症猫的生存时间延长无相关性（分别为771[718-1558]天对152[82-1852]天，P = 0.991）。
对医源性甲状腺功能减退（根据促甲状腺激素刺激试验结果诊断）的非氮血症猫补充左甲状腺素可提高生存时间，尽管仍需要进行随机对照试验。
