A Revised View on Equine Hypertriglyceridemia, Hyperlipidemia, and Hyperlipemia.

Equine hypertriglyceridemia refers to high triglycerides in the blood of horses, donkeys, and related species and is often triggered by a negative energy balance from illness, but it can also occur in well-eating animals with certain endocrine or muscle and liver disorders or after specific medications. This review argues that many equids can have high triglycerides without obvious illness, prompting a reexamination of what these elevations mean clinically and emphasizing restoration of energy balance and correction of underlying causes.

What this article reevaluates

• Whether hypertriglyceridemia, hyperlipidemia, and hyperlipemia should be viewed as equivalent clinical states versus a continuum with differing significance.
• The assumption that high triglyceride (TG) concentrations in equids invariably cause clinical illness, given evidence that some animals tolerate marked elevations without signs.
• How clinicians should prioritize management: focus on restoring energy balance and correcting triggers rather than reacting to TG numbers alone.

Background and terminology

• Traditional usage in equine medicine has often treated “hypertriglyceridemia,” “hyperlipidemia,” and “hyperlipemia” as overlapping or synonymous terms.
• The review highlights that TG elevation is common across breeds and ages and most often develops secondary to negative energy balance, but the clinical impact of a given TG value is variable.
• Because equids can exhibit substantially increased TG without clinical signs, the paper urges caution in equating any TG rise with disease severity.

Why triglycerides rise in equids

• Primary driver: negative energy balance from decreased intake, increased energy demand, or both—frequently secondary to another disease process.
• Documented scenarios with elevated TG despite animals continuing to eat:
  • Endocrinopathies (for example, disorders affecting insulin/glucose regulation).
  • Atypical myopathy (a severe muscle disorder linked to toxic exposures).
  • Severe liver disease (impaired lipid processing and export).
  • Use of sodium–glucose cotransporter 2 (SGLT2) inhibitors (a medication class affecting glucose handling).
• These contexts suggest multiple pathways to TG elevation, not solely starvation or anorexia.

Key insights from the revised view

• High TG alone may not reliably predict clinical illness; some equids remain clinically normal despite markedly increased concentrations.
• The presence or absence of clinical signs likely depends more on the underlying disease and overall metabolic state than on TG magnitude alone.
• Until the direct consequences of elevated TG are better defined, proactive reduction of TG via restoring energy balance and addressing triggers remains prudent.

Clinical recognition and diagnostic framing

• Do not rely solely on visual plasma “lipemia” or a single TG value to gauge risk; interpret TG alongside history, appetite, body condition, and concurrent illness.
• Evaluate for common triggers:
  • Recent illness or stressors that reduce feed intake.
  • Endocrine disease indicators (e.g., signs of insulin dysregulation or other hormonal disorders).
  • Muscle disease signs compatible with atypical myopathy.
  • Evidence of hepatic dysfunction.
  • Recent initiation of SGLT2 inhibitors or other medications affecting metabolism.
• Because TG can be high in well-eating animals, a thorough clinical assessment is essential to avoid over- or under-interpreting laboratory findings.

Management implications

• Primary objective: establish a positive energy balance.
  • Prompt nutritional support tailored to the individual and underlying condition.
  • Reduce catabolic drivers (pain, fever, inflammation) that increase energy demand.
• Treat the underlying endocrine or systemic disease contributing to TG elevation.
• Discontinue or reconsider medications (notably SGLT2 inhibitors) temporally associated with rising TG, when clinically appropriate.
• Given uncertainty about the direct toxicity of TG at different thresholds, err on the side of intervention while avoiding reflexive treatment based on numbers alone.

Special scenarios highlighted

• Endocrinopathies: TG can increase even in animals that are eating; endocrine evaluation and targeted therapy may normalize TG without aggressive lipid-specific interventions.
• Atypical myopathy: profound muscle injury can coexist with high TG; management should prioritize the myopathy while supporting energy balance.
• Severe liver disease: impaired lipid handling may drive TG elevation; focus on liver-friendly nutritional strategies and treating hepatic disease.
• Medication-associated cases: monitor TG after starting SGLT2 inhibitors; consider alternative therapies if significant elevations occur.

Unanswered questions and research needs

• Which TG thresholds, if any, predict organ dysfunction or adverse outcomes in different equid populations?
• What mechanisms explain tolerance of high TG in some animals versus rapid decompensation in others?
• How do specific diseases (endocrine disorders, myopathies, hepatic conditions) differentially modulate lipid metabolism in equids?
• What monitoring strategies best balance early detection with avoidance of overtreatment?

Practical takeaways

• High TG is common, often secondary to another problem, and not always synonymous with clinical deterioration.
• Prioritize restoring energy balance and correcting underlying disease or medication triggers.
• Interpret TG values in clinical context; avoid making management decisions based on numbers alone when the animal is otherwise stable.
• Because the consequences of elevated TG are not fully defined, timely, proportionate interventions are reasonable while evidence evolves.