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Vanden Broecke E, Stammeleer L, Stock E, De Paepe E, Daminet S. Efficacy of Urine Asymmetric Dimethylarginine Concentration to Predict Azotemia in Hyperthyroid Cats After Radio-Iodine Treatment. J Vet Intern Med 2025; 39:e70096. [PMID: 40271736 PMCID: PMC12019304 DOI: 10.1111/jvim.70096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2024] [Revised: 03/26/2025] [Accepted: 04/01/2025] [Indexed: 04/25/2025] Open
Abstract
BACKGROUND Hyperthyroidism can mask concurrent chronic kidney disease in cats, and no accurate biomarkers are available to predict which cats will develop renal azotemia after radioiodine (131I) treatment. HYPOTHESIS/OBJECTIVES To evaluate the potential of serum and urinary metabolites and metabolite ratios to predict post-131I renal azotemia in hyperthyroid cats. ANIMALS Hyperthyroid cats (n = 31), before and (3-12 months) after treatment with 131I at the Faculty of Veterinary Medicine (Ghent University, Belgium). METHODS Retrospective study. Optimized and validated feline extraction and analysis protocols were employed for metabolic profiling of urine and serum samples using ultra-high performance liquid chromatography-high-resolution mass spectrometry. A dual strategy of cross-validated univariate and penalized multivariate logistic regression was applied to determine predictivity (i.e., area under the curve [AUC], accuracy, sensitivity, and specificity) of individual biomarkers and panels. RESULTS All hyperthyroid cats were non-azotemic before 131I administration. After 131I treatment, 7 cats became persistently (≥ 2 timepoints) azotemic while 24 remained non-azotemic. Urinary asymmetric dimethylarginine (ADMA) was identified as a pivotal predictor of post-131I azotemia in both univariate and multivariate modeling. When employed as a standalone biomarker, an AUC of 0.851, accuracy of 0.903, sensitivity of 0.714, and specificity of 0.958 were achieved. While pre-treatment USG was significantly different (P = 0.002) between both groups, it did not show enhanced prediction over ADMA, nor in multivariate modeling. CONCLUSIONS AND CLINICAL IMPORTANCE Urinary ADMA can accurately predict post-131I azotemia in hyperthyroid cats becoming euthyroid after 131I treatment. These findings can aid clinicians in managing owner expectations and modify treatment plans.
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Affiliation(s)
- Ellen Vanden Broecke
- Small Animal DepartmentFaculty of Veterinary Medicine, Ghent UniversityMerelbekeBelgium
- Laboratory of Integrative Metabolomics (LIMET), Department of Translational Physiology, Infectiology and Public HealthFaculty of Veterinary Medicine, Ghent UniversityMerelbekeBelgium
| | - Lisa Stammeleer
- Small Animal DepartmentFaculty of Veterinary Medicine, Ghent UniversityMerelbekeBelgium
| | - Emmelie Stock
- Department of Morphology, Imaging, Orthopedics, Rehabilitation and NutritionFaculty of Veterinary Medicine, Ghent UniversityMerelbekeBelgium
| | - Ellen De Paepe
- Laboratory of Integrative Metabolomics (LIMET), Department of Translational Physiology, Infectiology and Public HealthFaculty of Veterinary Medicine, Ghent UniversityMerelbekeBelgium
| | - Sylvie Daminet
- Small Animal DepartmentFaculty of Veterinary Medicine, Ghent UniversityMerelbekeBelgium
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Cattaneo G, Kingsbury EJ, McCallum KE, Williams TL. Association of Serum Symmetric Dimethylarginine Concentrations and Inflammation in Cats. J Vet Intern Med 2025; 39:e70030. [PMID: 40008808 PMCID: PMC11863204 DOI: 10.1111/jvim.70030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2024] [Revised: 02/05/2025] [Accepted: 02/05/2025] [Indexed: 02/27/2025] Open
Abstract
BACKGROUND Serum symmetric dimethylarginine (SDMA) concentrations are higher in some hyperthyroid cats with normal renal function, presumably due to increased protein catabolism. OBJECTIVES To investigate if SDMA is higher in cats with inflammation (defined as elevated serum amyloid A [SAA]). ANIMALS Twenty-eight cats: 12 with elevated SAA concentrations (> 3.9 μg/mL) and 16 with normal SAA. METHODS Retrospective case control study. Cats presenting to a referral institution between 2016 and 2022 with a documented SAA were identified. Individuals with renal and extrarenal factors known to affect SDMA were excluded. SDMA was measured from stored serum samples. Comparisons were made using the Mann-Whitney U test, and correlations assessed using Spearman's correlation coefficient. Data are presented as median [minimum-maximum]. RESULTS SDMA was not significantly different between cats with elevated SAA and normal SAA (11 [5-17] μg/dL vs. 13 [9-21] μg/dL, respectively; p = 0.28). There was no correlation between SDMA and SAA (rs = -0.105; p = 0.594) or serum TT4 concentrations (rs = -0.023; p = 0.906). No difference in age or USG was present between elevated SAA and normal SAA groups (p = 0.908 and p = 0.165, respectively). Serum urea and creatinine concentrations were both significantly lower in cats with elevated SAA compared to those with normal SAA (6.3 [3.6-8.8] mmol/L vs. 8.4 [6.2-10.5] mmol/L; p = 0.008, and 96 [62-129] μmol/L vs. 118 [90-147] μmol/L; p = 0.008, respectively). CONCLUSIONS AND CLINICAL IMPORTANCE SDMA might be a more representative biomarker of GFR during inflammatory states, provided other confounding factors that affect SDMA are eliminated.
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Affiliation(s)
- Giulia Cattaneo
- Department of Veterinary Medicine, The Queen's Veterinary School Hospital (QVSH)University of CambridgeCambridgeUK
| | - Edward J. Kingsbury
- Department of Veterinary Medicine, The Queen's Veterinary School Hospital (QVSH)University of CambridgeCambridgeUK
| | - Katie E. McCallum
- Department of Veterinary Medicine, The Queen's Veterinary School Hospital (QVSH)University of CambridgeCambridgeUK
| | - Tim L. Williams
- Department of Veterinary Medicine, The Queen's Veterinary School Hospital (QVSH)University of CambridgeCambridgeUK
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Han Z, Chen L, Peng H, Zheng H, Lin Y, Peng F, Fan Y, Xie X, Yang S, Wang Z, Yuan L, Wei X, Chen H. The role of thyroid hormone in the renal immune microenvironment. Int Immunopharmacol 2023; 119:110172. [PMID: 37086678 DOI: 10.1016/j.intimp.2023.110172] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 03/29/2023] [Accepted: 04/07/2023] [Indexed: 04/24/2023]
Abstract
Thyroid hormones are essential for proper kidney growth and development. The kidney is not only the organ of thyroid hormone metabolism but also the target organ of thyroid hormone. Kidney disease is a common type of kidney damage, mainly including different types of acute kidney injury, chronic kidney disease, diabetic nephropathy, lupus nephritis, and renal cell carcinoma. The kidney is often damaged by an immune response directed against its antigens or a systemic immune response. A variety of immune cells in the innate and adaptive immune systems, including neutrophils, macrophages, dendritic cells, T lymphocytes, and B lymphocytes, is essential for maintaining immune homeostasis and preventing autoimmune kidney disease. Recent studies have found that thyroid hormone plays an indispensable role in the immune microenvironment of various kidney diseases. Thyroid hormones regulate the activity of neutrophils, and dendritic cells express triiodothyronine receptors. Compared to hypothyroidism, hyperthyroidism has a greater effect on neutrophils. Furthermore, in adaptive immune systems, thyroid hormone may activate T lymphocytes through several underlying mechanisms, such as mediating NF-κB, protein kinase C signalling pathways, and β-adrenergic receptors, leading to increased T lymphocyte activation. The present review discusses the effects of thyroid hormone metabolism regulation in the immune microenvironment on the function of various immune cells, especially neutrophils, macrophages, dendritic cells, T lymphocytes, and B lymphocytes. Although there are not enough data at this stage to conclude the clinical relevance of these findings, thyroid hormone metabolism may influence autoimmune kidney disease by regulating the renal immune microenvironment.
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Affiliation(s)
- Zhongyu Han
- School of Medical and Life Sciences, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Liuyan Chen
- School of Medical and Life Sciences, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Hongyao Peng
- School of Medical and Life Sciences, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Hongying Zheng
- School of Medical and Life Sciences, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Yumeng Lin
- Eye School of Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Fang Peng
- School of Medical and Life Sciences, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Yunhe Fan
- School of Medical and Life Sciences, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Xiuli Xie
- School of Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Simin Yang
- School of Medical and Life Sciences, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Zhanzhan Wang
- Lianyungang Clinical Medical College of Nanjing Medical University, Lianyungang, China
| | - Lan Yuan
- School of Medical and Life Sciences, Chengdu University of Traditional Chinese Medicine, Chengdu, China.
| | - Xiuyan Wei
- School of Medical and Life Sciences, Chengdu University of Traditional Chinese Medicine, Chengdu, China.
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Van Vertloo LR, Palerme JS, Miles KG, Bourgois-Mochel A, Jergens AE. Changes in symmetric dimethylarginine and glomerular filtration rates in hyperthyroid cats undergoing radioiodine therapy. J Feline Med Surg 2023; 25:1098612X231160128. [PMID: 36892005 PMCID: PMC10812008 DOI: 10.1177/1098612x231160128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/10/2023]
Abstract
OBJECTIVES The aims of this study were to evaluate concentrations of symmetric dimethylarginine (SDMA) in hyperthyroid cats before and after radioiodine treatment, and to compare results with other variables used to assess kidney function in cats (creatinine, urine specific gravity [USG] and glomerular filtration rate [GFR] measured by renal scintigraphy). METHODS Thirteen cats diagnosed with hyperthyroidism based on clinical signs and increased serum total thyroxine (TT4) were included in this prospective study. Study design included physical examination, complete blood count, serum chemistry, TT4, urinalysis and SDMA before treatment (T0) and at 1 month (T1) and 3 months post-treatment (T3). GFR was quantified by renal scintigraphy at T0 and T3. RESULTS Median GFR decreased significantly from baseline (3.18 ml/kg/min; range 1.35-4.87) at T3 (2.22 ml/kg/min; range 1.81-3.42 [P = 0.005]). While median creatinine and serum urea nitrogen increased post-treatment (creatinine: T0 = 0.8 mg/dl [range 0.4-1.1], T1 = 1.3 mg/dl [range 0.9-2]; T3 = 1.65 mg/dl [range 0.8-2.8]; P <0.001; serum urea nitrogen: T0 = 23 mg/dl [range 15-26]; T1 = 27 mg/dl [range 20-40]; T3 = 27.5 mg/dl [range 20-36]; P <0.001), SDMA and USG did not change significantly (SDMA: T0 = 11 µg/dl [range 7-15]; T1 = 12 µg/dl [range 6-16]; T3 = 10.5 µg/dl [range 8-21]; P = 0.789; USG: T0 = 1.030 [range 1.011-1.059]; T1 = 1.035 [range 1.012-1.044]; T3 = 1.030 [range 1.007-1.055]; P = 0.792). CONCLUSIONS AND RELEVANCE Our data suggest that factors other than GFR may affect serum SDMA in hyperthyroid cats and that SDMA does not offer an advantage over other biomarkers traditionally used to predict changes in renal function following radioiodine therapy.
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Affiliation(s)
- Laura R Van Vertloo
- Department of Veterinary Clinical Sciences, Iowa State University College of Veterinary Medicine, Ames, IA, USA
| | - Jean-Sébastien Palerme
- Department of Veterinary Clinical Sciences, Iowa State University College of Veterinary Medicine, Ames, IA, USA
| | - Kristina G Miles
- Department of Veterinary Clinical Sciences, Iowa State University College of Veterinary Medicine, Ames, IA, USA
| | - Agnes Bourgois-Mochel
- Department of Veterinary Clinical Sciences, Iowa State University College of Veterinary Medicine, Ames, IA, USA
| | - Albert E Jergens
- Department of Veterinary Clinical Sciences, Iowa State University College of Veterinary Medicine, Ames, IA, USA
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Yu L, Lacorcia L, Johnstone T. Hyperthyroid cats and their kidneys: a literature review. Aust Vet J 2022; 100:415-432. [PMID: 35711100 PMCID: PMC9543258 DOI: 10.1111/avj.13179] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 04/28/2022] [Accepted: 05/01/2022] [Indexed: 11/28/2022]
Abstract
Hyperthyroidism and chronic kidney disease (CKD) are common diseases of geriatric cats, and often occur concurrently. Thus, a thorough understanding of the influence of thyroid function on renal function is of significant value for all feline practitioners. Among other effects, hyperthyroidism causes protein catabolism and increases renal blood flow and glomerular filtration rate (GFR). These effects render traditional renal markers insensitive for the detection of CKD in cats with uncontrolled hyperthyroidism. Furthermore, the development of iatrogenic hypothyroidism with over treatment of hyperthyroidism can be detrimental to renal function and may negatively affect long-term survival. This review discusses important diagnostic considerations of feline hyperthyroidism, as well as key treatment modalities, with an emphasis on the use of radioiodine and the importance of post treatment monitoring of thyroid and renal parameters. In Australia, a common curative treatment for cats with benign hyperthyroidism (i.e. thyroid hyperplasia or adenoma) is a fixed dose of orally administered radioiodine, regardless of the serum total thyroxine concentration at the time of diagnosis. This review discusses the long term outcomes of this standard of care in comparison with current, relevant research literature from around the world. Finally, this review explores the use of symmetric dimethylarginine (SDMA) in assessing renal function before and after treatment in hyperthyroid cats. SDMA correlates well with GFR and creatinine in non-hyperthyroid cats, but our understanding of its performance in hyperthyroid cats remains in its infancy.
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Affiliation(s)
- L Yu
- Veterinary Referral HospitalDandenongVictoriaAustralia
| | - L Lacorcia
- Veterinary Referral HospitalDandenongVictoriaAustralia
| | - T Johnstone
- Animal Referral Hospital, Essendon Fields72 Hargrave AvenueEssendon FieldsVictoria3041Australia
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Geddes R, Aguiar J. Feline Comorbidities: Balancing hyperthyroidism and concurrent chronic kidney disease. J Feline Med Surg 2022; 24:641-650. [PMID: 35481810 PMCID: PMC11107990 DOI: 10.1177/1098612x221090390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PRACTICAL RELEVANCE Both hyperthyroidism and chronic kidney disease (CKD) are common long-term conditions in older cats, which might be diagnosed concurrently or develop at different times. Hyperthyroidism may mask the presence of CKD, and vice versa, by various mechanisms that are described in this review. Hyperthyroidism treatment options should be carefully considered when CKD has also been diagnosed. CLINICAL CHALLENGES Although it can be difficult to diagnose hyperthyroidism and CKD simultaneously, given that one condition may mask the other, it is important to consider the presence of both diseases when examining an older cat presenting with vomiting, weight loss, polyuria/ polydipsia, anorexia or sarcopenia. The concurrent presence of hyperthyroidism and CKD requires careful monitoring of glomerular filtration rate biomarkers, and adequate and prompt support of kidney function when normal thyroid function is re-established. Iatrogenic hypothyroidism is a recognised complication of all of the treatment options for hyperthyroidism, and increases the risk of azotaemia. Therapy with levothyroxine is recommended for cats that are hypothyroid and azotaemic. EVIDENCE BASE The information in this review draws on current literature and guidelines related to the pathophysiology, diagnosis and treatment recommendations for feline hyperthyroidism and CKD.
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Affiliation(s)
- Rebecca Geddes
- Clinical Sciences and Services, Royal Veterinary College, University of London, London, UK
| | - Joana Aguiar
- Dick White Referrals, Station Farm, London Road, Six Mile Bottom, Cambridgeshire, UK
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Michael H, Szlosek D, Clements C, Mack R. Symmetrical Dimethylarginine: Evaluating Chronic Kidney Disease in the Era of Multiple Kidney Biomarkers. Vet Clin North Am Small Anim Pract 2022; 52:609-629. [DOI: 10.1016/j.cvsm.2022.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Nivy R, Chaim N, Hanael E, Sutton GA, Bruchim Y, Aroch I, Segev G. Prospective evaluation of 5 urinary biomarkers as predictors of acute kidney injury in nonazotemic, hospitalized dogs. J Vet Intern Med 2021; 35:2812-2820. [PMID: 34738653 PMCID: PMC8692222 DOI: 10.1111/jvim.16308] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 10/23/2021] [Accepted: 10/26/2021] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Early recognition of acute kidney injury (AKI) is hindered by current definitions and use of traditional, insensitive markers. HYPOTHESIS/OBJECTIVES Urinary (u) activity of γ-glutamyl transpeptidase (GGT) and alkaline phosphatase (ALP), and concentrations of heat-shock protein 70 (HSP70) and interleukins (ILs) -6 and -18, are predictive biomarkers for AKI and survival. ANIMALS Nonazotemic, hospitalized dogs (n = 118) and healthy controls (n = 20). METHODS A prospective observational study. Nonazotemic dogs at risk of AKI were recruited and their urinary biomarker concentrations were measured at presentation. Serum creatinine (sCr) and symmetric dimethylarginine (sSDMA) were measured daily until discharge/death. RESULTS The overall case fatality rate was 18.6%. Fifteen dogs (12.7%) developed AKI, which was associated with death (relative risk, 3.2; 95% confidence interval [CI], 1.57-6.55). All 5 urinary biomarkers were significantly higher in hospitalized dogs compared to controls, with minimal overlap. uHSP70/uCr, uGGT/uCr, and uIL-6/uCr at presentation were higher in dogs which later developed AKI. Areas under the receiver operator characteristic curve (AUROC) (95% CI) for the 3 biomarkers as predictors of AKI were 0.67 (0.51-0.83), 0.68 (0.55-0.81), and 0.78 (0.65-0.91), respectively. When they were categorically classified as elevated/normal, each additional elevated biomarker increased the odds for AKI (OR, 2.83; 95% CI, 1.23-6.52, P = .01). Agreement between sCr and sSDMA was poor (Cohen's kappa = .071). The AUROC of SDMA at presentation for AKI prediction was 0.73 (0.51-0.95). CONCLUSIONS AND CLINICAL IMPORTANCE Kidney injury was common, irrespective of subsequent worsening of azotemia or death. The predictive value of individual urinary biomarkers was reduced by moderate sensitivities and specificities. SDMA showed moderate discriminatory utility for AKI prediction, and often displayed discordant results with sCr.
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Affiliation(s)
- Ran Nivy
- The Hebrew University of Jerusalem, Koret School of Veterinary Medicine, Jerusalem, Israel
| | - Netanel Chaim
- The Hebrew University of Jerusalem, Koret School of Veterinary Medicine, Jerusalem, Israel
| | - Erez Hanael
- The Hebrew University of Jerusalem, Koret School of Veterinary Medicine, Jerusalem, Israel
| | - Gila Abells Sutton
- The Hebrew University of Jerusalem, Koret School of Veterinary Medicine, Jerusalem, Israel
| | - Yaron Bruchim
- The Hebrew University of Jerusalem, Koret School of Veterinary Medicine, Jerusalem, Israel
| | - Itamar Aroch
- The Hebrew University of Jerusalem, Koret School of Veterinary Medicine-Internal Medicine, Small Animals, Rehovot, Israel
| | - Gilad Segev
- The Hebrew University of Jerusalem, Koret School of Veterinary Medicine-Internal Medicine, Small Animals, Rehovot, Israel
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Mack RM, Hegarty E, McCrann DJ, Michael HT, Grauer GF. Longitudinal evaluation of symmetric dimethylarginine and concordance of kidney biomarkers in cats and dogs. Vet J 2021; 276:105732. [PMID: 34391920 DOI: 10.1016/j.tvjl.2021.105732] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 05/21/2021] [Accepted: 08/10/2021] [Indexed: 01/01/2023]
Abstract
Symmetric dimethylarginine (SDMA) is a sensitive surrogate marker for glomerular filtration rate; however, there are uncertainties as to how to interpret mild increases (SDMA 15-19 μg/dL). This descriptive study used retrospective data to evaluate whether cats or dogs that had initial SDMA values (at T0) within the reference interval followed by an increased SDMA (at T1) had persistently increased SDMA (at T2; measured from 14 days to 18 months following T1; Persistence Cohort), and if and when cats or dogs with persistently increased SDMA had increased creatinine up to 24 months (Concordance Cohort). The Persistence Cohort included 16,670 cats and 16,712 dogs. If SDMA at T1 was 15-19 μg/dL, the probability of persistence was 53% for cats and 42% for dogs, while creatinine was concurrently increased in 20% of cats and 18% of dogs. For comparison, if SDMA was not increased at T1 the probability of increased SDMA at recheck was only 20% for cats and 9% for dogs. For cats and dogs with a T1 SDMA of 15-19 μg/dL and with persistent increases at T2, the probability of increased creatinine at T1 was 20% for cats and 18% for dogs, rising to 61% and 55%, respectively, by 24 months. When SDMA at T1 was >25 μg/dL, creatinine was increased in 93% of cats and 92% of dogs by 24 months. Mildly increased SDMA results may provide an opportunity to identify some cats and dogs earlier in their kidney disease.
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Affiliation(s)
- R M Mack
- IDEXX, 1 IDEXX Drive, Westbrook, ME 04092, USA.
| | - E Hegarty
- IDEXX, 1 IDEXX Drive, Westbrook, ME 04092, USA
| | - D J McCrann
- IDEXX, 1 IDEXX Drive, Westbrook, ME 04092, USA
| | - H T Michael
- IDEXX, 1 IDEXX Drive, Westbrook, ME 04092, USA
| | - G F Grauer
- College of Veterinary Medicine, Kansas State University, A-111 Mosier Hall, Manhattan, KS 66506-5802, USA
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Yu L, Lacorcia L, Finch S, Johnstone T. Assessment of serum symmetric dimethylarginine and creatinine concentrations in hyperthyroid cats before and after a fixed dose of orally administered radioiodine. J Vet Intern Med 2020; 34:1423-1431. [PMID: 32506701 PMCID: PMC7379014 DOI: 10.1111/jvim.15831] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 05/22/2020] [Accepted: 05/22/2020] [Indexed: 12/11/2022] Open
Abstract
Background 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. Objectives 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. Animals Eighty client‐owned hyperthyroid cats. Methods 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. Results 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). Conclusions and clinical importance 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.
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Affiliation(s)
- Lucia Yu
- Translational Research and Small Animal Clinical Trial Study Group, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Victoria, Australia
| | - Lauren Lacorcia
- Translational Research and Small Animal Clinical Trial Study Group, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Victoria, Australia
| | - Sue Finch
- Statistical Consulting Centre and Melbourne Statistical Consulting Centre, The University of Melbourne, Victoria, Australia
| | - Thurid Johnstone
- Translational Research and Small Animal Clinical Trial Study Group, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Victoria, Australia
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