title: Research priorities, horse owner perceptions and practices regarding management and treatment for pituitary pars intermedia dysfunction (PPID)
Creators: name: Tatum, Rebecca
Publisher: name: University of Liverpool Repository
Year: 2021

description: Older horses now make up a significant proportion of the equine population, meaning that geriatric medicine is increasingly important. Pituitary pars intermedia dysfunction (PPID) is a progressive disease prevalent in older horses, however, studies investigating diagnosis, treatment and prognosis are limited. The evidence base needs to be built on to inform management and treatment approaches and improve quality of life (QoL) of horses with PPID. The aims of this thesis were to i) identify and prioritise key research questions regarding PPID; ii) investigate management, health care and treatment strategies undertaken by owners iii) understand owner perceptions of treatment and QoL. A four-phase mixed methods approach was applied. Phase one used patient and public involvement (PPI), to prioritise the top 10 unanswered research questions for PPID. The questions focused on disease progression, diagnostic accuracy, treatment efficacy and additional management/treatment strategies. Literature on PPID diagnosis and treatment was subsequently evaluated in two systematic reviews, which highlighted the lack of high-quality evidence regarding current protocols. Phase two comprised a cross-sectional questionnaire to evaluate management and treatment strategies undertaken by 374 participating owners of PPID cases. Most horses were treated with pergolide (86.9%), while 17.4% received an alternative/complementary treatment. Pergolide had a higher efficacy rating compared to alternative/complementary treatments (p&lt;0.001). PPID cases were perceived to have a very good QoL (median rating 9/10). Pergolide treatment was associated with an improvement in QoL rating since diagnosis (p=0.002). Phase three built on the cross-sectional data in a prospective cohort, using follow-up telephone questionnaires to describe changes over time. A subset of 72 horses were enrolled, contributing a total of 53.4 horse-years at risk (HYAR), with a median duration of follow-up of 330.7 days. For horses receiving pergolide (n=55), the dose remained the same throughout the follow-up period in 78.2%. QoL ratings remained unchanged in 43.5% of horses but decreased in 21.0%. Overall mortality rate was 20.6 deaths per 100 horse-years at risk (HYAR), while estimated incidence of laminitis was 15.7 new episodes per 100 HYAR and that of infection was 24.9 events per 100 HYAR. Finally, phase four used qualitative semi-structured interviews with ten purposively selected owners to understand key topics surrounding care and QoL for PPID cases. Six overarching themes were identified; disease tangibility, balancing management and treatment complexities, owners being experts in their own horse, having a horse centered approach, the vet-owner relationship and how health and happiness go ‘hand in hand’. The themes demonstrated how owner decisions were influenced by the impact of PPID on the horse’s daily life and the visible changes observed. This perception was then framed by the owners’ understanding of the disease, their in-depth knowledge of what is normal for their horse and the nature of the vet-owner relationship. This thesis introduces the concept of PPI methodology in to equine veterinary research and provides novel information on the management, treatment and prognosis of PPID. It also highlights the lack of high-quality evidence on which clinical decisions are made. Pergolide treatment was associated with an increase in QoL but did not appear to influence morbidities or mortality. Owner experiences and perceptions play an important part in the treatment and management decisions made. The findings presented will help to develop effective management and treatment strategies to improve the QoL of horses with PPID. Owner perspectives and behaviours will also inform effective ways of communicating with owners about how to provide the best possible care.