The application of a new laminitis scoring method to model the rate and pattern of improvement from equine endocrinopathic laminitis in a clinical setting

Abstract

Background Endocrinopathic, or hyperinsulinaemia-associated laminitis (HAL) is a common and debilitating equine foot disease, and although no pharmacological treatments are registered, several are under development. To evaluate the effect of such treatments, an accurate and consistent method is needed to track the clinical signs of laminitis over time, and the natural history of the disease, in terms of a ‘normal’ pattern of improvement, needs to be understood. This study examined the improvement pattern in clinical cases of naturally-occurring HAL subjected to a range of best-practice interventions, using two different scoring methods. Eighty horses and ponies with suspected HAL were enrolled in a study conducted at 16 veterinary practices across Germany. The severity of laminitis was assessed by independent veterinarians using both the traditional Obel method and a modified Obel method developed by Meier and colleagues. Assessments were made on the day of diagnosis (d 0), then on days 4, 9, 14, 25 and 42 during the intervention period. Pain medications were withheld for 24 h prior to clinical examination in all cases. Results Time to marked improvement from laminitis varied between individuals, but was difficult to monitor accurately using the Obel method, with the median grade being 2/4 on days 0 and 4, then 0/4 from d 9 onwards. More subtle changes could be identified using the Meier method, however, and the median scores were seen to follow the form of an exponential decay model in most horses, improving from 8/12 on d 0, to 0/12 on d 25. Within this composite scoring method, considerable variation was observed in the rate of improvement of individual clinical signs, with the average time taken for each sign to reach a median score of 0 ranging from 4 days (foot lift and weight shifting) to 25 days (gait when turned in a circle) across all 80 horses. Conclusions The Meier method provides a reliable and consistent method for monitoring the clinical status of horses with HAL, and despite the variability, the pattern of improvement described here should provide a useful benchmark against which individual cases and new treatments can be assessed.

Preliminary observations on the use of ertugliflozin in the management of hyperinsulinaemia and laminitis in 51 horses: A case series

“…Horses were not included if follow-up was not available, other treatments that might affect insulin concentrations (for example metformin or levothyroxine) had been administered or if diet was altered during or within 6 weeks prior to the administration of ertugliflozin to avoid these potentially confounding effects on insulin concentrations. Clinical data retrieved included modified Obel lameness scores (Meier et al, 2021) and measures of adiposity including the estimated weight assessed with a validated weigh tape (Virbac) and measurements of neck circumference (Martinson et al, 2014), heart girth (Martinson et al, 2014) and abdominal girth (Jones et al, 1989). In accordance with practice protocols, blood samples had been collected consistently 90 min after the provision of forage for the assessment of insulin concentration.…”

Effect of sirolimus on insulin dynamics in horses

“…Tissue insulin resistance was not directly assessed in this study. Although insulin resistance is a component of ID in many horses, blood insulin concentration has been demonstrated to be directly associated with the development, recurrence, and recovery from laminitis 4 , 5 , 7 , 44 ; therefore the effect of sirolimus on blood insulin concentrations after carbohydrate challenge was the focus of the current study.…”

“…Although insulin resistance is a component of ID in many horses, blood insulin concentration has been demonstrated to be directly associated with the development, recurrence, and recovery from laminitis 4,5,7,44 ; therefore the effect of sirolimus on blood insulin Sirolimus has been investigated in other species 45 and the PKs appear to be non-linear, varying between species and with different dosing regimens. 46 Pharmacokinetics of a single intravenous dose of sirolimus (0.5 and 0.05 mg/kg) in the rabbit demonstrated dosedependent, nonlinear PKs and delayed clearance (terminal half-life: 768.6 ± 128.4 min; clearance: 0.977 ± 0.279 mL/min/kg at 0.05 mg/kg).…”

“…Laminitis most commonly affects horses with an underlying endocrinopathy: either pituitary pars intermedia dysfunction or equine metabolic syndrome. 1 , 2 , 3 The central role of insulin dysregulation (ID), specifically hyperinsulinemia, in the development of endocrinopathic laminitis has been established through multiple studies using experimental models, 4 , 5 , 6 , 7 prompting introduction of the term “hyperinsulinemia‐associated laminitis” (HAL) to describe this form of laminitis. 1 , 2 Although restriction of dietary non‐structural carbohydrates remains a mainstay of ID management in horses, 8 , 9 pharmaceutical control of the exaggerated post‐prandial insulinemic response would assist in the prevention of HAL.…”

Oral sugar test responses to ertugliflozin in ten horses with insulin dysregulation

“…Horse weight was estimated using a validated weight tape (Virbac) and body condition scored out of 9 using a validated scale (Henneke et al., 1983). Lameness was graded using the modified Obel scale and scored out of 12 as per a previously described protocol (Meier et al., 2021).…”