Translational Research and Small Animal Clinical Trial Study Group, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Victoria, Australia.
Statistical Consulting Centre and Melbourne Statistical Consulting Centre, The University of Melbourne, Victoria, Australia.
J Vet Intern Med. 2020 Jul;34(4):1423-1431. doi: 10.1111/jvim.15831. Epub 2020 Jun 7.
Serum symmetric dimethylarginine (SDMA) is a sensitive renal biomarker for detecting early chronic kidney disease (CKD) in nonhyperthyroid cats, but knowledge regarding its performance in hyperthyroid cats remains limited.
To determine the relationship between serum SDMA, creatinine and total thyroxine (TT4) concentrations in hyperthyroid cats before (T0) and 3 months after (T1) receiving a PO fixed dose of radioiodine.
Eighty client-owned hyperthyroid cats.
Prospective cohort study. Serum TT4, and SDMA, creatinine concentrations, and urine specific gravity were measured at T0 and T1. Nonparametric tests were used to determine the relationship among SDMA, and creatinine and TT4 concentrations. Agreement between SDMA and creatinine regarding CKD staging at both time points was assessed using Goodman and Kruskal's gamma statistic.
Mean serum SDMA concentration increased after treatment of hyperthyroidism. However, 21 of 75 cats experienced a decrease in SDMA between T0 and T1, whereas creatinine decreased in only 2 cats. A moderate correlation between SDMA and creatinine was seen at T1 (r = 0.53; P < .001) but not at T0 (r = 0.13; P = .25). Where assessable at T1, poor agreement was observed between SDMA and creatinine and CKD stage (Goodman and Kruskal's gamma 0.20; P = .29).
Discordant outcomes between SDMA and creatinine after radioiodine treatment in cats with hyperthyroidism suggest extrarenal factors may interfere with the reliability of SDMA to adequately reflect renal function. As a result, SDMA should not be interpreted in isolation in hyperthyroid cats treated with radioiodine.
血清对称二甲基精氨酸（SDMA）是一种敏感的肾脏生物标志物，可用于检测非甲状腺功能亢进猫的早期慢性肾脏病（CKD），但关于其在甲状腺功能亢进猫中的性能的知识仍然有限。
确定甲状腺功能亢进猫在接受 PO 固定剂量放射性碘治疗前（T0）和 3 个月后（T1）血清 SDMA、肌酐和总甲状腺素（TT4）浓度之间的关系。
80 只患有甲状腺功能亢进的宠物猫。
前瞻性队列研究。在 T0 和 T1 时测量血清 TT4、SDMA、肌酐浓度和尿比重。使用非参数检验确定 SDMA 与肌酐和 TT4 浓度之间的关系。使用 Goodman 和 Kruskal 的 gamma 统计评估 SDMA 和肌酐在两个时间点的 CKD 分期之间的一致性。
甲状腺功能亢进治疗后，血清 SDMA 浓度平均升高。然而，在 75 只猫中有 21 只在 T0 和 T1 之间 SDMA 降低，而只有 2 只猫的肌酐降低。在 T1 时，SDMA 与肌酐之间存在中度相关性（r = 0.53；P <.001），而在 T0 时则无相关性（r = 0.13；P =.25）。在 T1 时可评估的情况下，SDMA 和肌酐与 CKD 分期之间的一致性较差（Goodman 和 Kruskal 的 gamma 0.20；P =.29）。
甲状腺功能亢进猫接受放射性碘治疗后 SDMA 和肌酐的结果不一致表明，肾外因素可能干扰 SDMA 的可靠性，使其无法充分反映肾功能。因此，在接受放射性碘治疗的甲状腺功能亢进猫中，不应单独解释 SDMA。
