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.

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BackgroundLong‐term medical management of hypersomatotropism (HS) in cats has proved unrewarding. Pasireotide, a novel somatostatin analogue, decreases serum insulin‐like growth factor 1 (IGF‐1) and improves insulin sensitivity in cats with HS when administered as a short‐acting preparation.ObjectivesAssess once‐monthly administration of long‐acting pasireotide (pasireotide LAR) for treatment of cats with HS.AnimalsFourteen cats with HS, diagnosed based on diabetes mellitus, pituitary enlargement, and serum IGF‐1 > 1000 ng/mL.MethodsUncontrolled, prospective cohort study. Cats received pasireotide LAR (6–8 mg/kg SC) once monthly for 6 months. Fructosamine and IGF‐1 concentrations, and 12‐hour blood glucose curves (BGCs) were assessed at baseline and then monthly. Product of fructosamine concentration and insulin dose was calculated as an indicator of insulin resistance (Insulin Resistance Index). Linear mixed‐effects modeling assessed for significant change in fructosamine, IGF‐1, mean blood glucose (MBG) of BGCs, insulin dose (U/kg) and Insulin Resistance Index.ResultsEight cats completed the trial. Three cats entered diabetic remission. Median IGF‐1 (baseline: 1962 ng/mL [range 1051–2000 ng/mL]; month 6: 1253 ng/mL [524–1987 ng/mL]; P < .001) and median Insulin Resistance Index (baseline: 812 μmolU/L kg [173–3565 μmolU/L kg]; month 6: 135 μmolU/L kg [0–443 μmolU/L kg]; P = .001) decreased significantly. No significant change was found in mean fructosamine (baseline: 494 ± 127 μmol/L; month 6: 319 ± 113.3 μmol/L; P = .07) or MBG (baseline: 347.7 ± 111.0 mg/dL; month 6: 319.5 ± 113.3 mg/dL; P = .11), despite a significant decrease in median insulin dose (baseline: 1.5 [0.4–5.2] U/kg; 6 months: 0.3 [0.0–1.4] U/kg; P < .001). Adverse events included diarrhea (n = 11), hypoglycemia (n = 5), and worsening polyphagia (n = 2).Conclusions and Clinical ImportancePasireotide LAR is the first drug to show potential as a long‐term management option for cats with HS.

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The prevalence of type B blood in non-pedigree cats is higher than previously suggested and shows high variability within the UK; because of this, blood typing all feline patients, not only the ones of a breed typically known to have higher prevalence of type B blood before transfusion, is absolutely necessary to avoid a fatal transfusion reaction.

Diabetes mellitus (DM) is one of the most common feline endocrinopathies. Pancreatitis is a reported cause for poor control of DM in cats; however, its prevalence in diabetic cats is unknown. Measurement of serum feline pancreatic lipase immunoreactivity (fPLI) has been proposed as a sensitive and specific test for the detection of pancreatitis in cats. The aim of this study was to assess fPLI concentrations in diabetic cats and compare these with non-diabetic cats of similar age. Samples from 29 cats with DM and 23 non-diabetic cats were analysed. Serum fPLI concentrations were significantly higher in samples from diabetic cats (P<0.01). A weak association was found between serum fructosamine and fPLI concentrations (R(2)=0.355, P=0.015), but there was no association between fPLI concentrations and the degree of diabetic control. There were no significant differences in reported clinical signs between cats with or without DM regardless of serum fPLI concentration. This is the first study to demonstrate elevated serum fPLI concentrations in cats with DM, suggesting that pancreatitis could be a significant comorbidity in these cats.

BackgroundFeline hypersomatotropism (HST) is a cause of diabetes mellitus in cats. Pasireotide is a novel multireceptor ligand somatostatin analog that improves biochemical control of humans with HST.Hypothesis/ObjectivesPasireotide improves biochemical control of HST and diabetes mellitus in cats.AnimalsHypersomatotropism was diagnosed in diabetic cats with serum insulin‐like growth factor‐1 (IGF‐1) concentration >1,000 ng/mL by radioimmunoassay and pituitary enlargement.MethodsInsulin‐like growth factor 1 was measured and glycemic control assessed using a 12‐hour blood glucose curve on days 1 and 5. On days 2, 3, and 4, cats received 0.03 mg/kg pasireotide SC q12h. IGF‐1, insulin dose, and estimated insulin sensitivity (product of the area under the blood glucose curve [BGC] and insulin dose) were compared pre‐ and post treatment. Paired t‐tests or Wilcoxon signed rank tests were employed for comparison where appropriate; a linear mixed model was created to compare BGC results.ResultsInsulin‐like growth factor 1 decreased in all 12 cats that completed the study (median [range] day 1: 2,000 ng/mL [1,051–2,000] and day 5: 1,105 ng/mL [380–1,727], P = .002, Wilcoxon signed rank test). Insulin dose was lower on day 5 than on day 1 (mean reduction 1.3 [0–2.7] units/kg/injection, P = .003, paired t‐test). The product of insulin dose and area under the BGC was lower on day 5 than day 1 (difference of means: 1,912; SD, 1523; u × mg/dL × hours, P = .001; paired t‐test). No clinically relevant adverse effects were encountered.ConclusionsShort‐acting pasireotide rapidly decreased IGF‐1 in cats with HST and insulin‐dependent diabetes. The decrease in IGF‐1 was associated with increased insulin sensitivity.

Background: Hypersomatotropism (HST) is an increasingly recognized endocrinopathy in cats and is mostly described associated with diabetes mellitus (DM). Objectives: To evaluate the efficacy and safety of transsphenoidal hypophysectomy in treating HST and DM in cats. Animals: Sixty-eight client-owned cats with HST and DM treated by transsphenoidal hypophysectomy. Methods: Retrospective cohort study. Medical records were reviewed for glycemic control and serum insulin-like growth factor-1 (IGF-1) concentrations. Postoperative complications, death within 4 weeks, and proportion achieving diabetic remission were recorded. Survival times and DM-free intervals were calculated. Results: Fifty-eight cats (85.3%) were alive 4 weeks postoperatively with 10 (15%) postoperative deaths. Complications included hypoglycemia (n = 9), electrolyte imbalance (n = 9), and transient congestive heart failure (n = 5). Fifty-five cats (95% of 58 surviving cats [81% of all cats undergoing surgery]) had improved control of diabetes. Diabetic remission occurred in 41 cats (71% of 58 surviving cats [60% of all cats]) with insulin administration discontinued after a median of 9 days (range, 2-120). Postoperative 4-week serum IGF-1 concentration nadir was significantly lower in cats achieving diabetic remission (median 20 ng/mL [15-708] than those that did not (324 ng/mL [15-1955]; P = .03). All cats received long-term levothyroxine and hydrocortisone PO, alongside desmopressin (conjunctival) in 38 of 53 cats (72%). Recurrence of DM occurred in 5 of 41 cats (12%) after a median of 248 days (range, 84-1232). Median survival time of all cats was 853 days (range, 1-1740). Conclusions and Clinical Importance: Transsphenoidal hypophysectomy is an effective treatment for cats with HST and DM, with a long-term outcome that compares favorably to existing options.