Original Scientific Article
Hyperthyroidism in the domestic cat (Felis catus): informed treatment choice based on survival analysis
Fernando Mata*,
Ravneet Bhuller

Mac Vet Rev 2022; 45 (1): 71 - 78

10.2478/macvetrev-2022-0015

Received: 15 September 2021

Received in revised form: 06 February 2022

Accepted: 11 February 2022

Available Online First: 28 February 2022

Published on: 15 March 2022

Correspondence: Fernando Mata, fernandomata@ipvc.pt

Abstract

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.

Keywords: cats, hyperthyroidism, methimazole treatment, survivability, thyroidectomy


References

  1. 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.
  2. 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. https://doi.org/10.1016/j.cvsm.2020.06.004 PMid:32665137
  3. 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.
  4. Trepanier, L. (2006). Medical management of hyperthyroidism. Clin Tech Small Anim Pract. 21(1): 22-28. https://doi.org/10.1053/j.ctsap.2005.12.004 PMid:16584027
  5. 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
  6. 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. https://doi.org/10.1177/1098612X13519633 PMid:24423813
  7. 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. https://doi.org/10.1016/S1098-612X(02)00095-5
  8. Naan, E., Kirpensteijn, J., Kooistra, H., Peeters, M. (2006). Results of thyroidectomy in 101 cats with hyperthyroidism. Vet Surg. 35(3): 287-293. https://doi.org/10.1111/j.1532-950X.2006.00146.x PMid:16635010
  9. Peterson, M., Becker, D. (1995). Radioiodine treatment of 524 cats with hyperthyroidism. J Am Vet Med Assoc. 207(11): 1422-1428.
  10. 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. https://doi.org/10.1111/j.1939-1676.2001.tb02298.x PMid:11215911
  11. 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. https://doi.org/10.2460/javma.228.4.559 PMid:16478432
  12. 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. https://doi.org/10.1177/1098612X17718416 PMid:28699814
  13. 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. https://doi.org/10.1111/j.1939-1676.2010.0550.x PMid:20649748
  14. 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. https://doi.org/10.1111/j.1939-1676.2007.tb01941.x PMid:18196729
  15. Gunn-Moore, D. (2006). Considering old cats. J Small Anim Pract. 47(8): 430-431. https://doi.org/10.1111/j.1748-5827.2006.00199.x PMid:16911109
  16. 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. https://doi.org/10.1080/00480169.2005.36469 PMid:15731835
  17. 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. https://doi.org/10.1016/j.ygeno.2007.10.009 PMid:18060738 PMCid:PMC2267438
  18. 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. https://doi.org/10.1111/j.1365-2656.2011.01809.x PMid:21338353 PMCid:PMC6993175
  19. Scarlett, J., Moise, N., Rayl, J. (1988). Feline hyperthyroidism: a descriptive and case-control study. Prev Vet Med. 6(4): 295-309. https://doi.org/10.1016/0167-5877(88)90041-4
  20. 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. https://doi.org/10.1111/j.1939-1676.1999.tb02189.x PMid:10449223
  21. 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. https://doi.org/10.1016/j.jfms.2009.07.011 PMid:19712895
  22. 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. https://doi.org/10.1136/vr.157.7.185 PMid:16100367
  23. 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. https://doi.org/10.1111/j.1939-1676.2008.0163.x PMid:18691369
  24. 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. https://doi.org/10.1111/j.1748-5827.2008.00544.x PMid:18422499
  25. 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. https://doi.org/10.1016/j.domaniend.2008.10.001 PMid:19010632
  26. 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. https://doi.org/10.1111/j.1365-2265.2005.02236.x PMid:15807872
  27. Peterson, M., Kintzer, P., Hurvitz, A. (1988). Methimazole treatment of 262 cats with hyperthyroidism. J Vet Intern Med. 2(3): 150-157. https://doi.org/10.1111/j.1939-1676.1988.tb02812.x PMid:3265728
  28. 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


Copyright

© 2022 Mata F. This is an open-access article published under the terms of the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Conflict of Interest Statement

The authors have declared that no competing interests exist.

Citation Information

Macedonian Veterinary Review. Volume 45, Issue 1, Pages 71-78, e-ISSN 1857-7415, p-ISSN 1409-7621, DOI: 10.2478/macvetrev-2022-0015, 2022