Multimorbidity, behaviour and QoL in ageing dogs.

Older dogs frequently develop multiple chronic conditions, accompanied by behavioural and functional changes that may adversely affect their quality of life (QoL). However, the relative contributions of multimorbidity, behavioural manifestations, and functional performance to owner-perceived QoL remain incompletely understood. This cross-sectional study analysed anonymous online questionnaire responses from the owners of 789 dogs aged ≥ 8 years. Information on chronic health conditions, behavioural manifestations, functional performance, and owner-perceived QoL was collected using a structured questionnaire incorporating selected domains derived from the Canine Owner-Reported Quality of Life (CORQ) framework. Multivariable ordinal regression analyses showed that increased response to tactile stimulation (OR 2.65, 95% CI 1.70-4.13) and vocalisation without an apparent external stimulus (OR 2.04, 95% CI 1.49-2.79) were independently associated with poorer owner-perceived QoL after adjustment for age, cumulative health burden, and demographic variables, whereas cumulative health burden was not independently associated with the outcome. In a separate model, better mobility-related functional performance was independently associated with lower odds of poorer QoL (OR 0.56, 95% CI 0.52-0.61). These findings suggest that owner-observed behavioural and functional manifestations may provide clinically relevant information complementary to cumulative multimorbidity when evaluating the quality of life of ageing dogs. Recognition of such changes may support more comprehensive geriatric assessment and help identify problems that warrant further clinical evaluation and may be amenable to management. Given the cross-sectional design and owner-reported nature of the data, the observed associations should not be interpreted as causal.