Naturally occurring diabetes mellitus (DM) is common in domestic cats (Felis catus). It has been proposed as a model for human Type 2 DM given many shared features. Small case studies demonstrate feline DM also occurs as a result of insulin resistance due to a somatotrophinoma. The current study estimates the prevalence of hypersomatotropism or acromegaly in the largest cohort of diabetic cats to date, evaluates clinical presentation and ease of recognition. Diabetic cats were screened for hypersomatotropism using serum total insulin-like growth factor-1 (IGF-1; radioimmunoassay), followed by further evaluation of a subset of cases with suggestive IGF-1 (>1000 ng/ml) through pituitary imaging and/ or histopathology. Clinicians indicated pre-test suspicion for hypersomatotropism. In total 1221 diabetic cats were screened; 319 (26.1%) demonstrated a serum IGF-1>1000 ng/ml (95% confidence interval: 23.6–28.6%). Of these cats a subset of 63 (20%) underwent pituitary imaging and 56/63 (89%) had a pituitary tumour on computed tomography; an additional three on magnetic resonance imaging and one on necropsy. These data suggest a positive predictive value of serum IGF-1 for hypersomatotropism of 95% (95% confidence interval: 90–100%), thus suggesting the overall hypersomatotropism prevalence among UK diabetic cats to be 24.8% (95% confidence interval: 21.2–28.6%). Only 24% of clinicians indicated a strong pre-test suspicion; most hypersomatotropism cats did not display typical phenotypical acromegaly signs. The current data suggest hypersomatotropism screening should be considered when studying diabetic cats and opportunities exist for comparative acromegaly research, especially in light of the many detected communalities with the human disease.

Background: Diabetes mellitus (DM) management primarily focuses on improvement in blood glucose concentrations and clinical signs. A tool to assess the psychological and social impact of DM and its treatment on quality of life (QoL) previously has only been validated for feline DM. Hypothesis/Objectives: To validate a diabetic pet and owner-centered individualized measure of impact of DM (DIAQoL-pet) for diabetic dogs and their owners. Animals/Subjects: A total of 101 owners of insulin-treated diabetic dogs were recruited to complete the DIAQoL-pet. Methods: Discussions and pilot surveys with clinicians and owners of diabetic pets led to the design of 29 specific DM-associated QoL questions. Each item was scored according to impact frequency and perceived importance. An Item-Weighted-Impact-Score (IWIS) for each item was calculated, as was an Average-Weighted-Impact-Score (AWIS) by averaging all IWISs. Principal component analysis and Cronbach's α calculation assessed the measure's reliability. Results: The DIAQoL-pet showed high reliability (Communalities ≥0.5; Cronbach's α 0.85). The AWIS was −2.74 ± 1.7 (mean ± SD). Areas reported as most negatively impacting QoL included: “worry” (IWIS ± SD: −5.92 ± 4.3), “difficulties leaving dog with friends or family” (−5.68 ± 5.1), “worry vision” (−5.58 ± 4.6), “boarding difficulties” (−5.18 ± 5.2), “worry hypoglycemia” (−4.95 ± 4.3), “social life” (−4.82 ± 4.4), “costs” (−4.11 ± 4.7), and “future care”(−4.07 ± 4.6). Eighty-four percent of owners reported negative impact of DM on QoL. Conclusions and Clinical Importance: The DIAQoL-pet proved robust when used by owners of insulin-treated diabetic dogs and identified specific areas most negatively impacting dogs' and their owners' QoL. This tool could be used as an additional assessment parameter in clinical and research settings.

Practical relevance Clinicians who deal with diabetic cats can have mixed experiences. Some patients are ‘textbook cases’, responding very well to insulin administration; others prove to be more challenging. Recent studies have shown a significant proportion of problem diabetic cats to have underlying acromegaly (hypersomatotropism). Recognising this syndrome in these cats will be key to successfully managing the concurrent diabetes. Patient group Just like the ‘normal’ (non-acromegalic) diabetic cat, the acromegalic diabetic cat tends to be a middle-aged to older male neutered domestic short hair. However, with increasing case experience, this signalment may change. Most patients are insulin resistant, although this may not be the initial presenting sign. No breed predispositions have been recognised to date. Clinical challenges There is no single diagnostic test for feline acromegaly — a confident diagnosis relies on a combination of clinical signs, feline growth hormone and insulin-like growth factor 1 levels, and intracranial imaging. Additionally, the ideal treatment protocol has yet to be established. Currently, radiotherapy is considered by many to be the best treatment; however, costs, the need for multiple anaesthetics, and the often delayed and unpredictable treatment response represent serious limitations of this modality. Previously, medical treatment has proven unsuccessful. Recent studies provide some evidence in favour of, and some against, the use of newer long-acting somatostatin analogue preparations in a proportion of acromegalic cats. Evidence base Two recent studies have revealed a relatively high prevalence of acromegaly among diabetic cats. One also specifically assessed the value of hormonal tests, computed tomography and magnetic resonance imaging during the diagnostic process.

Background: Feline acromegaly has been reported infrequently in the veterinary literature and current knowledge of this endocrinopathy is based on limited numbers of animals with relatively advanced clinical signs. Hypothesis: This study was undertaken to screen diabetic cats for the presence of acromegaly. Animals: Diabetic cats with variable control examined by general practitioners in the United Kingdom. Methods: Blood samples were screened for the possible presence of acromegaly with basal serum concentrations of insulinlike growth factor 1 (IGF‐1) and, when available, feline growth hormone (fGH). In patients with markedly increased IGF‐1 concentrations intracranial computed tomography (CT) was offered, and in selected cats additional imaging was performed. Results: IGF‐1 was determined in 184 variably controlled diabetic cats; 59 cats had markedly increased IGF‐1 concentrations (.1,000 ng/mL; reference interval, 208–443 ng/mL). Eighteen cats subsequently were examined, and acromegaly was confirmed in 17 cats. Notable findings included absence of a detectable pituitary mass lesion in some affected cats regardless of whether CT or magnetic resonance imaging (MRI) was used. Hypertension was not found to be a complication in the evaluated cats and respiratory stridor was more prevalent than previously reported. Conclusions and Clinical Importance: Measurement of IGF‐1, growth hormone (GH), or both is useful in the diagnosis of acromegaly in cats.