Original ResearchLaminitis: Risk Factors and Outcome in a Group of Danish Horses
Introduction
Laminitis is a systemic condition that manifests in the foot and results in varying degrees of pain, lameness, and debilitation [1]. However, laminitis may best be regarded as a syndrome rather than a single disease entity because there are multiple inciting causes and possibly pathophysiological pathways [2]. Currently, it is considered that laminitis can be divided into three main categories [3]: (1) sepsis/systemic inflammatory conditions, (2) endocrine/metabolic, and (3) mechanical overload. Being able to identify those animals at increased risk of laminitis and the potential risk factors is obviously key to reducing the incidence of this condition (Harris et al 2009). Recent systematic reviews, however, have highlighted the lack of quality information with respect to the epidemiology of equine laminitis, including data on prevalence, inciting causes, and risk factors [4], [5]. The studies, that are available, suggest that factors associated with the individual animal and their management may be key as illustrated by the most recent published UK owner-reported survey [6]. This work suggested that the risk of laminitis was increased in the summer and winter compared with the spring and autumn, and in horses that had recently gained weight, had an owner-reported history of previous laminitis, lameness, or soreness after farriery, or had a concurrent endocrinopathy. In addition, there were certain managemental factors associated with increased risk.
Having suffered a previous bout of laminitis, however, may be a confounding issue in such studies, as it is likely to result in underlying physiological or metabolic changes that may change the risk factors from those associated with naive cases of laminitis. Another potential confounding factor in the previous study by Wylie et al was the use of owner-only reporting. The aim of this case-control study, therefore, was to identify risk factors for animals suffering laminitis for the first time in Denmark using veterinarians in equine practice. Additionally, animals that had suffered any episode of laminitis, whether for the first time or following one or more previous episodes, were monitored over the subsequent 12-month period to record the outcome and incidence of repeated episodes in these two subgroups.
Section snippets
Material and Methods
Veterinarians in 20 equine only practices throughout Denmark participated. After identification of a laminitis case based on clinical examination (backed by clinical guidance from the study web site), the veterinarian registered the horse and owner (with their permission) via an online database. The next nonlaminitic horse/pony (within ±2 years of age of this laminitis case) seen by that participating practice was registered as the matched control. Case-control pairs were therefore matched
Statistics
Descriptive statistics were created for all data and where appropriate chi-squared or Fisher exact tests were used to examine specific hypotheses related to level of work at 12 months and level of work at diagnosis or month of diagnosis.
Conditional logistic regression, with veterinary practice or surgeon as the matching variable, was conducted using NL as the outcome variable. All statistical analysis was performed using STATA/SE 12.1 (College Station, TX). A univariable analysis was initially
Descriptive
One hundred and ten laminitis cases were recruited (61 female: 49 male; average age 13.5 years; range 2–34 years) and 80 control animals (33 female: 47 male; average age 12.2 years; range 2–25 years). There was no significant difference in age or gender between cases and controls.
There were 69 NL and 41 chronic cases; 60.5% of the laminitics were obese compared with 33% of the controls (BCS of ≥7/9) [10].
Time of Year of Diagnosis
Most cases of laminitis were diagnosed in June (see Fig. 1).
Outcome
Within 12 months from
Discussion
This study looked at the risk factors for new episodes of laminitis and also monitored the outcome of any animal suffering from laminitis over the 12 months after the initial diagnosis and enrollment.
Conclusion
This veterinarian led study into laminitis risk factors highlights the importance of grass turnout and breed. Further work is needed to evaluate the interaction between these two key factors. It also highlights the important role that a change in grass intake, both type and particularly amount, may play at any time of the year not only the spring as commonly thought.
Acknowledgments
The authors do not have any conflict of interest.
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