Cabergoline treatment in cats with diabetes mellitus and hypersomatotropism

Abstract

Objectives The aim of this study was to evaluate the safety and efficacy of cabergoline to control hypersomatotropism (HST) and diabetes mellitus (DM) in cats. Methods This was a prospective cohort study. Twenty-three cats with HST and concurrent DM were enrolled. Cats received a dose of 10 μg/kg cabergoline q48h PO for 6 months. Serum insulin-like growth factor 1 (IGF-1) and fructosamine concentrations, insulin dose and Insulin Resistance Index (IRI) were measured at the time of diagnosis of HST and at the start of cabergoline treatment (t0), and 3 months (t1) and 6 months (t2) during cabergoline treatment. Results A decrease and normalization of serum IGF-1 concentration was observed in 35% and 26% of cats, respectively. Median IGF-1 (t0: 1350 ng/ml [range 832–1501]; t1: 1284 ng/ml [range 365–1501]; t2: 1240 ng/ml [range 263–1501]; P = 0.016) decreased significantly. Twelve cats underwent diagnostic imaging of the pituitary area. The median pituitary height at t0 of cats that experienced an IGF-1 reduction (n = 5/12) was significantly lower compared with those that did not experience an IGF-1 reduction (n = 7/12) (3.2 mm [range 3.1–3.7] vs 6 mm [range 3.5–9.5]; P = 0.011). Median fructosamine (t0: 628 µmol/l [range 400–963]; t1: 404 µmol/l [range 249–780]; t2: 400 µmol/l [range 260–815]; P <0.0001), insulin dose (t0: 1.3 IU/kg [range 0.5–4.6]; t0: 0.5 IU/kg [range 0–2.3]; t2: 0.4 IU/kg [range 0–2.1]; P <0.0001) and IRI (t0: 800 µmolIU/kgl [range 257–2700]; t1: 300 µmolIU/kgl [range 0–1498]; t2: 250 µmolIU/kgl [range 0–1498]; P <0.0001) decreased significantly during cabergoline treatment. Eight cats achieved diabetic remission between months 1 and 6 of cabergoline treatment (median time to achieve remission: 3 months [range 1–6]). Three cats experienced asymptomatic hypoglycemia. Conclusions and relevance Cabergoline was effective in normalizing IGF-1 concentration in 26% of cats. Cabergoline improved diabetes control and was associated with remission of DM in 35% of cases. Cabergoline could be a treatment option for cats with HST and DM, especially in those cases with a relatively small pituitary tumor.