Subclinical Pancreatitis is More Common in Overweight and Obese Dogs if Peak Postprandial Triglyceridemia is >445 mg/dl
In human beings, there is strong evidence that hypertriglyceridemia is associated with an increased risk for pancreatitis. Miniature Schnauzers with fasting hypertriglyceridemia have a higher risk of pancreatitis. The association of hypertriglyceridemia and pancreatitis has not been well characterized in other dogs. The aim of this study was to determine whether dogs with increased postprandial serum triglyceride concentrations are at increased risk of having serum pancreatic lipase immunoreactivity (cPLI) or trypsin-like immunoreactivity (cTLI) concentrations in the diagnostic range for exocrine pancreatic disease.
We recruited 36 client-owned, healthy (no vomiting, anorexia, abdominal pain) overweight or obese dogs (body condition score 6-9/9). Serum triglycerides were measured after a 24 hour fast and hourly for 12 hours after a meal (40% ME dietary fat) comprising 50% of daily maintenance energy requirement based on estimated lean body weight. Fasting serum cPLI (Spec cPLTM) concentrations higher than 400 µg/L and cTLI lower than 2.5 µg/L were used as cut-off values for pancreatitis and exocrine pancreatic insufficiency (EPI), respectively. Low, medium, and high cut-offs for hypertriglyceridemia were set a priori for fasting (90, 175, and 355 mg/dL), mean postprandial (90, 265, and 530 mg/dL), and peak postprandial (135, 445, and 885 mg/dL) triglycerides. Odds of elevated cPLI were compared using Fisher's Exact tests. Results are reported as likelihood ratios (LR)--the ratios of post- to pre-test odds.
Three of the 36 dogs had a fasting cPLI above the cut-off value for pancreatitis (pre-test odds 0.09). Eight dogs had peak triglycerides higher than 445 mg/dL, of which three had a cPLI above the diagnostic cut-off for pancreatitis (LR 6.6, p=0.008). Both dogs with peak postprandial serum triglycerides above 885 mg/dL had serum cPLI higher than the diagnostic cut-off for pancreatitis (LR infinite, p=0.005). Dogs that exceeded 445 mg/dL were identified with sensitivity of 75%, 88%, and 88% by postprandial samples collected at 2, 3, and 4 hours, respectively. Sensitivity was 100% when two samples were evaluated at either 2 and 4, or 3 and 4 hours. No significant association was found between any of the fasting or mean postprandial triglyceride concentrations and a cPLI above the cut-off value for pancreatitis. None of the dogs had a serum cTLI concentration below the diagnostic cut-off for EPI.
The odds of having serum cPLI concentration above the diagnostic cut-off for pancreatitis are about 7 times higher in overweight and obese dogs when peak postprandial triglyceridemia is >445 mg/dL after a standard meal with 40% ME fat fed at 50% MER. This information could allow development of a useful screening test to identify dogs that might benefit from dietary fat restriction because of increased risk of subclinical pancreatitis.