Epidemiology studies of insured dog and cats in Japan

The domestic dog and cat have become integral to modern human family life. The Japanese dog and cat populations are estimated to be 10.35 and 9.96 million, with 15.1% and 10.1% of Japanese households being estimated to own at least one dog or cat respectively. With the integration of companion animals into human life, the number of owners who want to have their pets to receive proper veterinary medical care increased. Knowing the pattern of disease occurrence of a defined animal population and the risk factors that may affect it, is important to maintain the health and prevent diseases in companion animals. It provides useful information that can be utilized by veterinary practitioners to guide diagnostic decision making, by breeders when planning breeding programs and by owner when acquiring a new pet. Despite substantial medical advances at the clinical level on diagnosis and treatment of diseases in individual animals, there is a shortage of epidemiological information in companion animals at population level. In recent years, epidemiological analysis of dog diseases have been conducted using data from referral hospitals, and data from veterinary primary-care practices and veterinary practices. The data from referral hospitals are accurate in regard to diagnosis but they have no information about the total population at risk and the possible selection bias when only cases are referred to them. The data from primary-care practices and veterinary practices are more representative of the national dog population than those from referral hospitals, but they have a selection bias when a large proportion of dogs are not registered with practices or when the practices participating in the study are not representative of the overall veterinary practice structure. Pet insurance data have been used for research purposes since the 1970's with increasing frequency during the last 15 years. Researchers have shown interest in pet insurance data because, although diagnostic information on insured animals may be inaccurate, they contain sound information relating to breed, sex and age of both diseased and healthy animals in the background population with less selection bias compared with data from referral hospitals and veterinary primary-care practices, and the insured population can be followed from enrolment to termination of coverage. Recently, epidemiological analysis by breed sex, age, and habitat has been conducted using data of insured dogs on mortality; mammary tumors, atopic dermatitis, lymphoma and bone tumors. Anicom, the leading pet insurer in Japan started its operation 17 years ago, and currently holds almost 600,000 pet insurance policies in force. I tried to investigate the prevalence of disease and longevity with analysis of the above data. We calculated the annual prevalence of diseases of 18 diagnostic categories in the insured dog population in Japan, using data from 299,555 dogs insured between April 2010 and March 2011. The prevalence was highest for dermatological disorders (22.9% for all, 22.6% for females and 23.3% for males), followed by otic diseases (16.8% for all, 16.4% for females and 17.2% for males) and digestive system disorders (16.1% for all, 15.7% for females and 16.4% for males). The prevalence of cardiovascular, urinary, neoplasia and endocrine disorders, increased with age; infectious diseases and injuries showed a high prevalence at young ages, and the prevalence of musculoskeletal and respiratory disorders showed a bimodal peak at young and old ages. A large variation in prevalence was observed between breeds for dermatological, otic, digestive, ophthalmological and cardiovascular disorders. The life expectancies and causes of death were evaluated with above data, of which 4169 dogs died during this period. The overall life expectancy of dogs was 13.7 years. Neoplasia resulted in the highest probability of death, especially in the large and giant breed groups. Cardiovascular system disorders were the second major cause of death. The accumulated animal health insurance claim data for dogs seem to be useful for development of veterinary prophylactic medicine and improvement of quality of life for family animals.