Development and Psychometric Evaluation of an Owner-Completed Health-Related Quality of Life and Treatment Satisfaction Measure in Feline Osteoarthritis: The FeOA-QoL-TS

OBJECTIVES:

Feline osteoarthritis (OA) causes pain and mobility impairment. This can reduce cat quality of life (QoL), owner QoL and owners’ satisfaction with, and adherence to, treatments. No existing feline OA-specific measure exists that assesses all three concepts. The current study developed and psychometrically evaluated a novel owner-completed Feline OA-specific assessment of cat and owner QoL and Treatment Satisfaction (FeOA-QoL-TS).

METHODS:

The FeOA-QoL-TS measure was developed using a conceptual model derived from a meta-synthesis of published literature and supplementary review, followed by cognitive interviews with eight owners of cats with OA, to evaluate content validity. To evaluate the measure’s psychometric properties, a draft version of the FeOA-QoL-TS was administered, across six timepoints in a Phase 4 field study, to owners of OA treated cats (N=139).

RESULTS:

Based on interview findings, 16 items were reworded, six removed, and three added; resulting in 25 items that were well understood and considered relevant. Recall period and response options were well understood and considered appropriate to almost all owners. Item-level analyses and confirmatory factor analysis supported deletion of five further items, and calculation of three domain scores (Cat QoL, Owner QoL and Treatment Satisfaction), with acceptable model fit, as hypothesised by the earlier conceptual model. The resulting 20-item FeOA-QoL-TS demonstrated good internal consistency and test-retest reliability. Convergent validity was supported by strong correlations with concurrent measures and significant differences for known-groups comparisons of different QoL states. Effect sizes were larger for improved compared to stable groups, supporting its ability to detect improvement in cat and owner QoL. Anchor-based analyses supported -1.0 and -0.9 point responder definitions for Cat and Owner QoL domains, respectively.

CONCLUSIONS:

Findings support the content validity of the FeOA-QoL-TS in feline OA. The 20-item FeOA-QoL-TS instrument is a reliable and valid instrument to measure feline and owner QoL and treatment satisfaction.