Association between radiographic assessment of hip status and subsequent incidence of veterinary care and mortality related to hip dysplasia in insured Swedish dogs.
Department of Animal Breeding and Genetics, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, P.O. 7023, SE-750 07 Uppsala, Sweden. Sofia.Malm@hgen.slu.se
Our objective was to evaluate the association between grading of hip status as assessed by radiographic examination (hip screening) and subsequent incidence of veterinary care and mortality related to hip dysplasia (HD) in five breeds of insured dogs in Sweden. Screening results for hip status from the Swedish Kennel Club and data on veterinary care and mortality from the insurance company Agria were merged based on the registration number of the dog. Dogs of five breeds (Bernese Mountain Dogs, German Shepherds, Golden Retrievers, Labrador Retrievers, and Rottweilers) screened during 1995-2004 and covered by an insurance plan for veterinary care or life at the time of screening were included. The study populations included between 1667 and 10,663 dogs per breed. Breed-specific multivariable Cox proportional-hazards analyses were performed to evaluate the impact of radiographic hip status on time from hip screening to first HD-related veterinary and life claim, respectively. The effects of gender, birth season, and a time-varying covariate of year were also studied. Additional analyses, on the five breeds combined, were performed to investigate the effects of hip status, breed, and the interaction between hip status and breed. The effect of hip status was highly significant (P