Efficacy of hypophysectomy for the treatment of hypersomatotropism‐induced diabetes mellitus in 68 cats

Abstract 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.