Lipoma in dogs under primary veterinary care in the UK: prevalence and breed associations

BACKGROUND: Lipomas are masses of mesenchymal origin, comprising of adipocytes, and are often clinically unremarkable but can be alarming to owners. Although lipomas are reportedly common in dogs, no studies have specifically investigated risk factors associated with their occurrence. This study was a large-scale retrospective analysis of electronic patient records of dogs attending practices participating in VetCompass™. Univariable and multivariable logistic regression methods were used to evaluate associations between risk factors and primary-care veterinary diagnosis of lipoma. RESULTS: From 384,284 dogs under veterinary care during 2013 at 215 primary practice clinics in the UK, there were 2765 lipoma cases identified giving a one-year prevalence of 1.94% (95% CI: 1.87–2.01). Breeds with the highest lipoma prevalence included Weimaraner (7.84%, 95% CI 6.46–9.40), Dobermann Pinscher (6.96%, 95% CI 5.67–8.44), German Pointer (5.23%, 95% CI 3.93–6.80), Springer Spaniel (5.19%, 95% CI 4.76–5.66), and Labrador Retriever (5.15%, 95% CI 4.90–5.41). Dogs with an adult bodyweight equal or higher than their breed/sex mean had 1.96 (95% CI 1.81–2.14, P < 0.001) times the odds of lipoma compared with dogs that weighed below their breed/sex mean. The odds of lipoma increased as adult bodyweight increased. Increased age was strongly associated with increasing odds of lipoma. Compared with dogs aged 3.0 to < 6.0 years, dogs aged 9.0 - < 12.0 years had 17.52 times the odds (95% CI 14.71–20.85, P < 0.001) of lipoma. Neutered males (OR: 1.99, 95% CI 1.69–2.36, P < 0.001) and neutered females (OR: 1.62, 95% CI 1.37–1.91, P < 0.001) had higher odds than entire females. Insured dogs had 1.78 (95% CI 1.53–2.07, P < 0.001) times the odds of lipoma compared with uninsured dogs. CONCLUSIONS: Lipomas appear to be a relatively common diagnosis in primary-care practice. Certain breeds were identified with remarkably high lipoma prevalence, highlighting the risk that owners should be prepared for. Lipoma predisposition of larger bodyweight individuals within breed/sex suggests that being overweight or obese may be a predisposing factor but would need further work to confirm.