Initial Evidence to Support the Use of a Generic Health-Related Quality of Life Instrument to Measure Chronic Pain in Cats with Osteoarthritis

Introduction: Currently, instruments to measure feline chronic pain focus on functional changes, whereas health-related quality of life (HRQL) encompasses emotional as well as physical well-being. VetMetrica for cats, a 20-item web-based generic HRQL instrument generates scores in three HRQL domains (vitality, comfort, emotional wellbeing [EWB]). This study aimed to investigate its use as a measure of chronic pain in OA.

Materials and Methods: Owners of healthy cats and cats with OA completed an assessment and the attending clinician categorized OA severity, identified co-morbidities and completed a clinical assessment for a sub group of cats. Score differences for healthy, mild OA and moderate/severe OA were investigated with non-parametric statistics (Mann–Whitney) and the relationship between clinical assessment scores and domain scores with Pearson’s Coefficient.

Results: Owners of 77 cats (38 healthy, 17 males, 21 females, median age 3 [1–10]; 39 OA [14 mild, 25 moderate/severe], 21 males, 18 females, median age 14 [3–20]) completed an assessment. 31 OA cats had co-morbidities (median 3, range 1–6). Eleven healthy and 30 OA cats had clinical assessments. Differences in medians in healthy vs. mild, healthy vs. moderate/severe and mild vs. moderate/severe OA were, for vitality 0.72 (p = 0.001), 1.57 (p ≤ 0.001), 0.81 (p = 0.002; for comfort 0.4 (p = 0.001), 1.28 (p =< 0.001), 0.74 (p = 0.003), for EWB 0.38 (p = 0.002), 0.93 (p =< 0.001), 0.5 (p = 0.001) respectively. Pearson’s coefficients for vitality, comfort, EWB were 0.70 (strong), 0.61 (strong) and 0.52 (moderate), respectively.

Conclusion: Despite its limitations (unmatched age profiles and prevalence of co-morbidities) the study provided initial evidence to support the use of validated HRQL instruments for OA pain measurement.

Acknowledgements: Jacky Reid is the Director and Cory Noble an employee of NewMetrica Ltd, a company that provides VetMetrica under commercial license for clinical trials. Thank you to Scottish Enterprise and Boehringer Ingelheim for providing financial support for the project.