ORIGINAL_ARTICLE Hyperthyroidism is the most frequently diagnosed endocrine disorder in cats. Therapy may include pharmacological, surgical (thyroidectomy), radioactive (iodine), and dietary treatment. The choice of treatment is believed to be strongly influenced by the veterinarian’s experience, level of education, and knowledge of the current scientific literature. The history of survival rates can affect the decision for treatment by both the veterinarian and the owner. This study aimed to explore the longevity in cats diagnosed with hyperthyroidism and to identify significant variables which affect survival rates by using retrospective data from the practice. A multivariate Cox regression was applied with the following results: surgical thyroidectomy and methimazole medication produced similar longevity (median 23.5 months, P>0.05); Domestic Short Hair cats survived longer than pure breeds (median 27.2 vs 9.4 months, P < 0.05); as do cats without chronic renal disease (median 28.1 vs 6.2 months, P < 0.001); and those with low activities of alanine aminotransferase (median 27.1 vs 17.0 months, P < 0.01). Hyperthyroidism is comorbid with renal diseases, but no cumulative effect was found on survivability. There was no difference in survival rates between surgical and pharmaceutical treatment, therefore the discussion of treatment options with owners can focus on other factors (e.g., cost, owners’ compliance, cats’ tolerance to medication, presence of comorbidities). We propose that surgery may be the preferred treatment when the survival rates are expected to be higher than one year. This would avoid high costs and potential side effects of medication. https://macvetrev.mk/Files/Article/2022/10.2478/macvetrev-2022-0015/macvetrev-2022-0015.pdf 2022-03-15T09:00:00 71 78 10.2478/macvetrev-2022-0015 cats hyperthyroidism methimazole treatment survivability thyroidectomy Fernando Mata fernandomata@ipvc.pt false 1 Center for Research and Development in Agri-food Systems and Sustainability (CISAS), Instituto Politécnico de Viana do Castelo, Rua Escola Industrial e Comercial Nun’Alvares 4900-347, Viana do Castelo, Portugal LEAD_AUTHOR Ravneet Bhuller false 2 National Institute for Biological Standards and Control, Blanche Lane, South Mimms, Potters Bar, Hertfordshire, EN6 3QG, United Kingdom AUTHOR Broussard, J., Peterson, M., Fox, P. (1995). Changes in clinical and laboratory findings in cats with hyperthyroidism from 1983 to 1993. J Am Vet Med Assoc. 206(3): 302-305. 1 Peterson, M. (2020). Hyperthyroidism in cats: considering the impact of treatment modality on quality of life for cats and their wwners. Vet Clin North Am Small Anim Pract. 50(5): 1065-1084. PMid:32665137 2 10.1016/j.cvsm.2020.06.004 Peterson, M., Kintzer, P., Cavanagh, P., Fox, P., Fergusson, D., Johnson, G., Becker, D. (1983). Feline hyperthyroidism: pretreatment clinical and laboratory evaluation of 131 cases. J Am Vet Med Assoc. 183(1): 103-110. 3 Trepanier, L. (2006). Medical management of hyperthyroidism. Clin Tech Small Anim Pract. 21(1): 22-28. PMid:16584027 4 10.1053/j.ctsap.2005.12.004 Forrester, S., Towell, T., Shenoy, K. (2012). Nutritional management of feline hyperthyroidism. Conference Proceedings of the Veterinary Medical Association, 130th Annual Meeting, Iowa: p.87-91 [cited 2022 February, 15] https://www.avmi.net/information/hyperthyroid-hints/nutritional-management-of-feline-hyperthyroidism 5 Higgs, P., Murray, J., Hibbert, A. (2014). Medical management and monitoring of the hyperthyroid cat: a survey of UK general practitioners. J Feline Med Surg. 16(10): 788-795. PMid:24423813 6 10.1177/1098612X13519633 Hofmann, G., Marks, S., Taboada, J., Hosgood, G., Wolfsheimer, K. (2003). Transdermal methimazole treatment in cats with hyperthyroidism. J Feline Med Surg. 5(2): 77-82. 7 10.1016/S1098-612X(02)00095-5 Naan, E., Kirpensteijn, J., Kooistra, H., Peeters, M. (2006). Results of thyroidectomy in 101 cats with hyperthyroidism. Vet Surg. 35(3): 287-293. PMid:16635010 8 10.1111/j.1532-950X.2006.00146.x Peterson, M., Becker, D. (1995). Radioiodine treatment of 524 cats with hyperthyroidism. J Am Vet Med Assoc. 207(11): 1422-1428. 9 Slater, M., Geller, S., Rogers, K. (2001). Long-term health and predictors of survival for hyperthyroid cats treated with iodine 131. J Vet Intern Med. 15(1): 47-51. PMid:11215911 10 10.1111/j.1939-1676.2001.tb02298.x Milner, R., Channell, C., Levy, J., Schaer, M. (2006). Survival times for cats with hyperthyroidism treated with iodine 131, methimazole, or both: 167 cases (1996-2003). J Am Vet Med Assoc. 228(4): 559-563. PMid:16478432 11 10.2460/javma.228.4.559 Vagney, M., Desquilbet, L., Reyes-Gomez, E., Delisle, F., Devauchelle, P., Rodriguez-Piñeiro, M., Rosenberg, D., Fornel-Thibaud, P. (2018). Survival times for cats with hyperthyroidism treated with a 3.35 mCi iodine-131 dose: a retrospective study of 96 cases. J Feline Med Surg. 20(6): 528-534. PMid:28699814 12 10.1177/1098612X17718416 Williams, T., Peak, K., Brodbelt, D., Elliot, J., Syme, H. (2010). Survival and the development of azotemia after treatment of hyperthyroid cats. J Vet Intern Med. 24(4): 863-869. PMid:20649748 13 10.1111/j.1939-1676.2010.0550.x Berent, A., Drobatz, K., Ziemer, L., Johnson, V., Ward, C. (2007). Liver function in cats with hyperthyroidism before and after 131I therapy. J Vet Intern Med. 21(6): 1217-1223. PMid:18196729 14 10.1111/j.1939-1676.2007.tb01941.x Gunn-Moore, D. (2006). Considering old cats. J Small Anim Pract. 47(8): 430-431. PMid:16911109 15 10.1111/j.1748-5827.2006.00199.x Olczac, J., Jones, B., Pfeiffer, D., Squires, R., Morris, R., Markwell, P., (2005). Multivariate analysis of risk factors for feline hyperthyroidism in New Zealand. N Z Vet J. 53(1): 53-58. PMid:15731835 16 10.1080/00480169.2005.36469 Lipinski, M., Froenicke, L., Baysac, K., Billings, N., Leutenegger, C., Levy, A., Longeri, M., et al. (2008). The ascent of cat breeds: genetic evaluations of breeds and worldwide random-bred populations. Genomics 91(1): 12-21. PMid:18060738 PMCid:PMC2267438 17 10.1016/j.ygeno.2007.10.009 Benson, J., Hostetler, J., Onorato, D., Johnson, W., Roelke, M., O’Brien, S., Jansen, D., Oli, M. (2011). Intentional genetic introgression influences survival of adults and subadults in a small, inbred felid population. J Anim Ecol. 80(5): 958-967. PMid:21338353 PMCid:PMC6993175 18 10.1111/j.1365-2656.2011.01809.x Scarlett, J., Moise, N., Rayl, J. (1988). Feline hyperthyroidism: a descriptive and case-control study. Prev Vet Med. 6(4): 295-309. 19 10.1016/0167-5877(88)90041-4 Kass, P., Peterson, M., Levy, J., James, K., Becker, D., Cowgill, L. (1999). Evaluation of environmental, nutritional, and host factors in cats with hyperthyroidism. J Vet Intern Med. 13(4): 323-329. PMid:10449223 20 10.1111/j.1939-1676.1999.tb02189.x Pittari, J., Rodan, I., Beekma, G., Gunn-Moore, D., Polzin, D., Taboada, J., Tuzio, H., Zoran, D. (2009). American association of feline practitioners. Senior care guidelines. J Feline Med Surg. 11(9): 763-778. PMid:19712895 21 10.1016/j.jfms.2009.07.011 Platinga, E., Everts, H., Kastelein, A., Breynan, A. (2005). Retrospective study of the survival of cats with acquired chronic renal insufficiency offered different commercial diets. Vet Rec. 157(7): 185-187. PMid:16100367 22 10.1136/vr.157.7.185 Boyd, L.M., Langston, C., Thompson, K., Zivin, K., Imanishi, M. (2008). Survival in cats with naturally occurring chronic kidney disease (2000-2002). J Vet Intern Med. 22(5): 1111-1117. PMid:18691369 23 10.1111/j.1939-1676.2008.0163.x Wakeling, J., Moore, K., Elliot, J., Syme, H. (2008). Diagnosis of hyperthyroidism in cats with mild chronic kidney disease. J Small Anim Pract. 49(6): 287-294. PMid:18422499 24 10.1111/j.1748-5827.2008.00544.x van Hoek, I., Lefebvre, H., Peremans, K., Meyer, E., Croubels, S., Vandermeulen, E., Kooistra, H., et al. (2009). Short- and long-term follow-up of glomerular and tubular renal markers of kidney function in hyperthyroid cats after treatment with radioiodine. Domest Anim Endocrinol. 36(1): 45-56. PMid:19010632 25 10.1016/j.domaniend.2008.10.001 den Hollander, J., Wulkan, R., Mantel, M., Berghout, A. (2005). Correlation between severity of thyroid dysfunction and renal function. Clin Endocrinol (Oxf). 62(4): 423-427. PMid:15807872 26 10.1111/j.1365-2265.2005.02236.x Peterson, M., Kintzer, P., Hurvitz, A. (1988). Methimazole treatment of 262 cats with hyperthyroidism. J Vet Intern Med. 2(3): 150-157. PMid:3265728 27 10.1111/j.1939-1676.1988.tb02812.x Scardale Vets. (2020). Springwood Vets. Radioiodin treatment of hyperthyroidism in cats. [cited 2020 November 12]. http://www.scarsdalevets.com/wp-content/uploads/2018/04/Radioiodine-Treatment-of-Hyperthyroidism-1.pdf 28