A cohort study of equine laminitis in Great Britain 2009-2011: Estimation of disease frequency and description of clinical signs in 577 cases

Reasons for performing studyA previous systematic review highlighted a lack of good evidence regarding the frequency of equine laminitis in Great Britain. ObjectivesTo estimate the frequency of veterinary-diagnosed active laminitis in the general horse population of Great Britain and to describe the clinical signs present in cases. Study designProspective cohort study. MethodsData on active episodes of equine laminitis were collected from veterinary practitioners. ResultsThe prevalence of veterinary-diagnosed active laminitis was 0.47% (95% confidence interval [CI] 0.42-0.52%) for the veterinary-attended population and 0.49% (95% CI 0.43-0.55%) for the veterinary-registered population, suggesting that active episodes of laminitis accounted for nearly one in 200 equine visits and occurred in nearly one in 200 horses registered with veterinary practices. The incidence of veterinary-diagnosed active laminitis was 0.5 cases per 100 horse-years at risk (95% CI 0.44-0.57). Laminitis occurred in all limbs, but most commonly affected the forelimbs bilaterally (53.5%, 95% CI 49.4-57.7%) and was most severe in the front feet. The most common clinical signs were increased digital pulses, difficulty turning and a short, stilted gait at walk. Conclusions and potential relevanceThe frequency of veterinary-diagnosed active laminitis was considerably lower than previously published estimates, which is probably due to differences in geographical setting, study period, case definition, study design and study populations.