Hormonal, clinical, and survival outcomes in horses and ponies diagnosed with pituitary pars intermedia dysfunction in primary care practice.

BACKGROUND: Variables associated with hormonal, clinical, and survival outcomes of equids with pituitary pars intermedia dysfunction (PPID) are incompletely investigated. HYPOTHESIS/OBJECTIVES: Evaluate the effect of initial hormone concentrations, clinical signs, treatment, and owner-related variables on outcomes in horses and ponies with PPID. ANIMALS: Medical records from 213 horses and ponies diagnosed with PPID by 2 university-based primary care practices. METHODS: Analytical observational cohort study. Variables associated with adrenocorticotropic hormone normalization, clinical improvement, and survival after diagnosis were assessed with Fisher's exact tests or Mann-Whitney U tests. Stepwise backward multivariable logistic regression models were performed to determine variables independently associated with outcomes of interest with report of odds ratios (ORs) and 95% CIs. RESULTS: Age at diagnosis (OR: 0.90 [95% CI, 0.84-0.97]; P = .003) and number of months between tests (OR: 0.96 [95% CI, 0.92-0.99]; P = .003) were associated with hormonal normalization after diagnosis. A body condition score (BCS) between 4 and 6/9 at diagnosis (OR: 15.07 [95% CI, 2.17-238.5]; P = .004) and median household income in the county of residence/1000 (MHI, OR: 1.17 [95% CI, 1.02-1.42]; P = .02) were associated with clinical improvement after diagnosis. Age at diagnosis (OR: 0.91 [95% CI, 0.85-0.98]; P = .01) and MHI (OR: 1.04 [95% CI, 1.01-1.07]; P = .02) were associated with survival after diagnosis. CONCLUSIONS AND CLINICAL IMPORTANCE: Diagnosis at a younger age, frequent monitoring, a healthy BCS, and the owner's financial means were associated with improved outcomes in horses managed for PPID.