A Comparison of the Survival Times of Dogs Treated with Mitotane or Trilostane for Pituitary-Dependent Hyperadrenocorticism

Abstract

The survival times of 148 dogs treated for pituitary-dependent hyperadrenocorticism were studied using clinical records from 3 UK veterinary centers between 1998 and 2003. Of these animals, 123 (83.1%) were treated with trilostane, while 25 (16.9%) were treated with mitotane. Treatment groups were compared using t-tests and analysis of variance (or their nonparametric equivalents) and chi-square tests. Survival data were analyzed using Kaplan-Meier survival plots and Cox proportional hazard methods. There was no significant difference between the population attributes from each center or between treatment groups. The median survival time for animals treated with trilostane was 662 days (range 8-1,971) and for mitotane it was 708 days (range 33-1,399). There were no significant differences between the survival times for animals treated with trilostane and those treated with mitotane. In the multivariable model (including drug, center, breed group, weight, diagnostic group, and age at diagnosis), only age at diagnosis and weight were significantly negatively associated with survival. Importantly, there was no significant effect of drug choice on survival.

Comparison of Survival Times for Dogs with Pituitary‐Dependent Hyperadrenocorticism in a Primary‐Care Hospital: Treated with Trilostane versus Untreated

“…36 Concerning age, other studies that included dogs treated with trilostane or mitotane have reported similar results. 33,35 In contrast, age was not reported to be associated with survival in another study that included dogs treated with trilostane, and our results are consistent with theirs. 32 The reason for this difference is not clear.…”

“…days. [32][33][34][35][36] In our study, median survival time was not reached for the trilostane group during the study period. Because the trilostane group in our study included fewer cases (n = 17) with a small number of cases at risk after 2 years, we conducted survival analysis at 2 years.…”

“…This study included dogs that were in middle and old age, and medium-and small-sized breeds, consistent with a previous large population study. 33 Poodles, which are known to be susceptible to PDH, were coincidently not included in this study. This may be attributable to differences in the popularities of these breeds among countries.…”

Pre‐trilostane and three‐hour post‐trilostane cortisol to monitor trilostane therapy in dogs

“…There are no studies demonstrating good correlation between a systematic evaluation of owners’ observations of clinical control and the post-ACTH stimulation cortisol. There is also a lack of consensus regarding the target post-ACTH stimulation cortisol concentration in trilostane-treated dogs with values varying from 15 to 250 nmol/l used to define good clinical control (Neiger and others 2002, Ruckstuhl and others 2002, Braddock and others 2003, Wenger and others 2004, Barker and others 2005, Galac and others 2010, Ramsey 2010). …”

Epidemiology of hyperadrenocorticism among 210,824 dogs attending primary‐care veterinary practices in the UK from 2009 to 2014

“…Several studies have described the clinical features of canine hyperadrenocorticism in the UK (Neiger et al 2002, Barker et al . 2005, Kenefick & Neiger 2008, Helm et al 2011, Augusto et al 2012 ).…”