Abstract

Canine osteoarthritis (OA) is a progressive and chronic disease that results in the destruction and deterioration of the cartilage surrounding synovial joints. It frequently presents with pain and lameness in dogs and can result in euthanasia. However, the pathogenesis and epidemiology of OA is poorly described in current literature. The aim of this study was to identify epidemiological information of OA such as the prevalence, severity, duration and risk factors contributing to the development of canine OA. This study also aimed to investigate how frequently relevant behavioural signs are recorded in primary care consultations and what pain-related behaviours dogs with OA exhibit. Firstly, the scientific literature was systematically searched following PRISMA (2009) guidelines, to produce a systematic review and meta-analysis on the risk factors that contribute to OA and its predisposing conditions. The second study included a cohort epidemiological study using primary care data from the VetCompass database combined with a case-control risk analysis to support the systematic review. In total forty-four papers were included in the final corpus of the systematic review, and four datasets were included in the meta-analysis. For the cohort study overall, 455,557 dogs were included in the study as a denominator population. 16,437 candidate OA cases were identified, of which 6102 (37%) were manually checked and 4196 were confirmed as osteoarthritis cases. The main findings in the systematic review showed OA is largely a genetic disorder exacerbated through lifestyle. The meta-analysis results showed females had greatest odds of developing cruciate ligament diseases (fixed effect odds (FE) 1.715, 95% confidence intervals (CI) 1.31 to 2.24; random effect odds (RE) 1.600, 95% CI 1.10 to 2.33) and hip and elbow dysplasia (FE 1.173, 95% CI 0.978 to 1.407; RE 1.129, 95% CI 0.777 to 1.640), and that males have greatest odds of developing OA (FE 2.489 95% CI 1.253 to 4.943; RE 2.274 95% CI 0.707 to 7.309). In the epidemiological study an estimated prevalence for OA was calculated at 2.5%, and average duration of OA was found to be 2 years, presenting for 11% of life. The average severity was 6 (range 13), with obesity (p<0.001) and duration (p=0.018) significantly affecting severity score. 19.6 % of cases had at least one behavioural problem reported in the EPR, with the top 3 behaviours being dog is quieter, reluctance to exercise and alteration to normal behaviour. The main risks found in the risk analysis were age, insurance status and breed group (all p<0.001). This shows OA affects thousands of individuals and can have an incredibly long duration. It also showed that behaviour discussions were recorded in just under a fifth of cases. Further investigations are warranted in order to support this study as well as to reduce the number of cases of OA, as this disease can seriously impact canine welfare.