Predictors of laminitis development in a cohort of nonlaminitic ponies

Knowles, EJ; Elliott, J; Harris, PA; Chang, YM; Menzies-Gow, NJ

Abstract

Background Quantifying risk factors for laminitis development requires improvement. Objectives To identify the most useful physical examination, metabolic and management factors to predict laminitis development in client-owned, nonlaminitic ponies. Study design Prospective cohort study. Methods Physical examination, metabolic and management data were collected from a pony cohort 6 monthly for up to 4 years. Ponies were monitored for the development of laminitis. Metabolic data included basal plasma concentrations of ACTH ([ACTH]), adiponectin ([adiponectin]), triglycerides and glucose. Serum insulin concentrations ([insulin]) were measured in the unfasted basal state ([insulin]T0) and 60 minutes ([insulin]T60) after administration of corn syrup (0.3ml/kg). Separate multivariable Cox proportional-hazards models were developed for physical, management/signalment and metabolic data and later combined into two final models. Low-, medium- and high-laminitis risk categories were defined based on basal or T60 [insulin]. Results Overall, 374 ponies (age 5-32 years) and 891 pony-years were included in the main analysis. Laminitis incidence (95% confidence interval (CI)) was 4.8 (3.5-6.5) cases/100 pony-years. Laminitis development was associated with numerous univariable factors. Significant (P < .05) factors retained in the final multivariable models included [insulin]T0, [insulin]T60, [adiponectin] and divergent hoof growth. [ACTH] was not independently associated with laminitis. Based on [Insulin]T0, low- (<21.6 mu IU/ml), medium- (21.6-45.2 mu IU/ml) and high-risk (>45.2 mu IU/ml) categories encompassed 70, 20 and 10% of the population and had estimated 4-year laminitis incidences (95%CI) of 6 (2-9)%, 22 (10-33)% and 69 (48-82)% respectively. Based on [Insulin]T60 the low- (<53.4 mu IU/ml), medium- (53.4-153 mu IU/ml) and high-risk (>= 153 mu IU/ml) categories comprised 60, 30 and 10% of the population and had estimated 4-year laminitis incidences (95%CI) of 3 (0-6)%, 20 (10-29)% and 73 (52-84)% respectively. Main limitations Results may not apply to different insulin assays, geographical regions, breeds or management types. Conclusions [Insulin]T0 or [insulin]T60 best quantify the risk of future laminitis development in nonlaminitic ponies.

Citation

Knowles, E., Elliott, J., Harris, P., Chang, Y., & Menzies-Gow, N. (2023). Predictors of laminitis development in a cohort of nonlaminitic ponies. Equine Veterinary Journal, https://doi.org/10.1111/evj.13572

• Journal Article Type: Article
• Acceptance Date: Feb 17, 2022
• Publication Date: Jan 2, 2023
• Deposit Date: Apr 25, 2023
• Publicly Available Date: Apr 28, 2023
• Print ISSN: 0425-1644
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• DOI: https://doi.org/10.1111/evj.13572
• Keywords: adiponectin; horse; insulin; laminitis; PPID; PASTURE-ASSOCIATED LAMINITIS; RISK-FACTORS; EQUINE LAMINITIS; INSULIN-RESISTANCE; HORSES; SURVIVAL; GLUCOSE; MODELS