Professor Universidade Federal do Rio Grande do Sul Porto Alegre, Rio Grande do Sul, Brazil
Abstract: Background – Hypersomatotropism (HST) is documented in ~15-33% of diabetic cats in different studies. The first Latin America epidemiological trial on HST prevalence found 14.9% HST prevalence among diabetic cats from Buenos Aires (Argentina). Hypothesis/Objectives – The HST prevalence among diabetic cats from Porto Alegre city, Southern Brazil, correlates with the reported prevalence in Buenos Aires city, about 850 km distant. Animals – A sample size of 33 patients was calculated (Epi Info Calculator) to find a HST prevalence of 15% among diabetic cats considering a 95% alfa and 80% power. Methods – Diabetic cats on insulin therapy for at last two months, without Cushing´s syndrome or hyperthyroidism were eligible. Patients were recruited by convenience among feline and endocrinology practitioners and submitted to a clinical, phenotypical, and laboratorial evaluation. Total T4 and IGF-1 were measured by the Immulite 2000 system (Siemens). A cut-off of IGF-1 > 746 ng/mL was assumed for HST diagnosis. Cats with IGF-1 higher than the upper limit of the reference interval (670 ng/mL) are invited to perform a pituitary CT scan. Results - Until this moment, 26 cats were evaluated, being 92.3% mixed breed and 65.4% males (90% neutered). The mean age was 10.7 ± 4.28 (2.5-22) years, and mean weight 5.4 ± 1.42 (2.85-9.4) kg. Mean IGF-1 among this population was 277 ± 134 (79,5-497) ng/mL. Conclusions and Clinical Importance – So far, the HST lower prevalence in this population raises questions regarding geographical differences in disease distribution, eventually due to different genetic and/or environmental backgrounds.
