Thyroid diseases in dogs and cats in Brazil: epidemiological evidence and clinical practice
DOI:
https://doi.org/10.31533/pubvet.v20n7e1990Keywords:
Epidemiology, hyperthyroidism, hypothyroidism, thyroidAbstract
This systematic review synthesized the Brazilian epidemiological evidence on feline hyperthyroidism and canine hypothyroidism and discussed their diagnostic implications for clinical practice. It represents a thematic subset of a broader systematic review previously registered on the Open Science Framework (DOI: 10.17605/OSF.IO/6AHXY), conducted in accordance with the Cochrane Handbook and the Joanna Briggs Institute guidance and reported following the PRISMA 2020 statement. Brazilian observational studies with clearly defined denominators and described diagnostic criteria were included. Four studies reported estimates of feline hyperthyroidism (n = 716; 105 cases), with proportions ranging from 3.3% (7/212) to 28.7% (51/178) and substantial heterogeneity (I² = 95.2%; P < 0.0001). For canine hypothyroidism, two studies (n = 10,976; 155 cases) reported markedly discrepant proportions (11.77% [154/1308] and 0.01% [1/9668]), with extreme heterogeneity (I² = 99.8%; P < 0.0001). These differences likely reflect variations in clinical setting, population tested, indications for diagnostic testing, and diagnostic confirmation criteria. Therefore, these estimates should not be interpreted as population prevalence but rather as measures of disease frequency within specific clinical case series. Overall, the available Brazilian evidence remains limited and heterogeneous, highlighting the need for standardized diagnostic criteria, greater transparency in reporting denominators, and well-designed epidemiological studies capable of generating more robust estimates. The findings also emphasize the importance of recognizing the risks of underdiagnosis of feline hyperthyroidism and overdiagnosis of canine hypothyroidism in routine clinical practice.
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