Increased insulin-like growth factor 1 concentrations in a population of non-diabetic cats with overweight/obesity

MICELI DD; ALEXIS JALIQUIAS, JORGE GARCÍA, FLORENCIA GALLELLI, CAROLINA VECINO; PIGNATARO OP

Barcelona

Congreso; ECVIM CONGRESS; 2023

Feline hypersomatotropism (HST) has been typically associated with diabetes mellitus (DM), whereas HST without concurrent DM had only been reported in a few case reports. Studies evaluating the prevalence of feline HST in the non-diabetic population are lacking. Weight gain may be observed in diabetic cats with HST. The aim of the study was to evaluate circulating insulin-like growth factor-1 (IGF-1) in non-diabetic cats with overweight/obesity and to screen this population for the presence of HST. In this prospective study, fifty-six cats with overweight/obesity from referral centers between March 2021 and March 2023 were evaluated. Serum IGF-1 was measured as part of the routine tests for overweight/obesity. Non-diabetic cats were included in the study if they had a body condition score (BCS) >6/9. Fifty-four cats were Domestic Short-Hair, 1 Domestic Long-Hair and 1 Siamese. Thirty-seven cats were neutered male and 19 cats were neutered female; median age was 8 years (range 2-15 years); median body weight was 7.6Kg (range 5.3-11Kg); 20 cats were classified as overweight (BCS 7/9), while 36 cats were classified as obese (BCS 8-9/9). Median serum IGF-1 concentrations were 589 ng/ml (range 123-2450 ng/ml). Median serum IGF-1 concentrations of cats with BCS 7/9, 8/9 and 9/9 were 562 ng/ml (range 123-1456 ng/ml), 566 ng/ml (range 151-1210 ng/ml), 608 ng/ml (range 284-2450 ng/ml), respectively. There was a positive linear correlation between serum IGF-1 concentrations and body weight (r= 0.36, 95% CI 0.1-0.57 P=0.006). Four out of 56 cats had IGF-1 concentrations >1000 ng/ml, resulting in a 7.1% (95% confidence interval 1.9-17.2%) HST prevalence rate in non-diabetic cats with overweight/obesity. Eight cats (14.3%) had IGF-1 concentrations between 800 and 1000 ng/ml. Intracranial imaging was performed in the four cats with IGF-1 concentrations >1000 ng/ml and pituitary enlargement was detected in 1/4 cases on computed tomography. All of these cats had phenotypic changes consistent with acromegaly: prognathia inferior (4/4), abdominal enlargement (3/4), weight gain (3/4), broad facial features (2/4), polyphagia (2/4), broadening of paws (2/4), respiratory stridor (1/4) and degenerative arthropathy (1/4). A proportion of 7.1 % of overweight/obese non-diabetic cats from referral centers had serum IGF-1 concentration and clinical signs compatible with HST/acromegaly. Likewise, serum IGF-1 concentrations had a positive correlation with body weight in this population of cats. This study highlights that HST should not be suspected only in diabetic cats and emphasizes the relevance of screening different populations of non-diabetic cats to increase the recognition of HST.