Development of a health-related quality-of-life (HRQoL) assessment tool for equines with Pituitary Pars Intermedia Dysfunction (PPID)

Menzies-Gow, Nicola; Knowles, Edward; Bouquet, Aline; Nicol, Christine

Abstract

Background: Clinical signs of pituitary pars intermedia dysfunction (PPID) are frequently mistaken for ‘normal’ aging and may not be optimally assessed. Objective quality of life (QoL) assessment could improve clinical decision-making.
Objectives: To develop an owner-reported QoL assessment tool for equines with PPID. To assess factors associated with QoL scores obtained using the tool.
Study design: Quantitative, cross-sectional study.
Methods: Tool development followed a standard psychometric process of item (any aspect of PPID and its management that could impact QoL) identification (following interviews with veterinarians, owners and clinical record reviews), selection (online owner questionnaire), and refinement (statistical analyses; chi-square and Cronbach’s alpha). QoL scores were further analysed using General Linear Models.
Results: Forty-two items associated with PPID were identified. Thirty-seven items were selected for the online questionnaire. In total, 612 complete responses (n=343 PPID and n=269 non-PPID horses) were obtained. Through stepwise statistical item refinement, 24 items remained in the final PPID-QoL tool (overall Cronbach’s =0.835). PPID-QoL scores ranged from 0 (best) to 1 (worst). Median (interquartile range) QoL scores were 0.33 (0.22-0.44) and 0.20 (0.14-0.27) for PPID and non-PPID horses respectively. QoL scores for all horses were worse if they had PPID (P<0.001) or other chronic medical conditions and were older (P<0.015). For PPID horses specifically, QoL scores were also worse if they had other chronic medical conditions (P=0.024), but QoL scores were not associated with current PPID treatment (treated vs untreated horses with a PPID diagnosis), body weight, age, breed, sex, or years since diagnosis.
Main limitations: Limited numbers of untreated PPID horses.
Conclusion: The QoL tool is valid and reliable for use in horses with PPID and can be applied in further research. PPID horses that had another chronic disease had a worse QoL score which should be considered when assessing QoL scores.

Citation

Menzies-Gow, N., Knowles, E., Bouquet, A., & Nicol, C. (2025). Development of a health-related quality-of-life (HRQoL) assessment tool for equines with Pituitary Pars Intermedia Dysfunction (PPID). Equine Veterinary Journal, https://doi.org/10.1111/evj.14513

• Journal Article Type: Article
• Acceptance Date: Mar 21, 2025
• Online Publication Date: May 2, 2025
• Publication Date: May 2, 2025
• Deposit Date: Oct 22, 2024
• Publicly Available Date: May 8, 2025
• Print ISSN: 0425-1644
• Electronic ISSN: 2042-3306
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• DOI: https://doi.org/10.1111/evj.14513
• Publisher URL: doi.org/10.1111/evj.14513