Is It Being Overdiagnosed? Feline Pancreatitis

SGLT2 inhibitor use in the management of feline diabetes mellitus

Sodium-glucose cotransporter-2 (SGLT2) inhibitors are routinely used in the management of human type 2 diabetes and have been shown to effectively mitigate hyperglycemia and reduce the risks of cardiovascular and renal compromise. Two SGLT2 inhibitors, namely bexagliflozin and velagliflozin, were recently FDA approved for the treatment of uncomplicated feline diabetes mellitus. These oral hypoglycemic agents are a suitable option for many newly diagnosed cats, with rapid improvements in glycemic control and clinical signs. Suitable candidates must have some residual β-cell function, as some endogenous insulin production is required to prevent ketosis. Appropriate patient selection and monitoring are necessary, and practitioners should be aware of serious complications such as euglycemic diabetic ketoacidosis.

Evaluation of Disease Spectrum in Hospitalized Cats with Hyperlipasemia: Pancreatitis Alone Is Rare, Hyperlipasemia without Suspected Pancreatitis Is Common

Histological evidence of pancreatitis is commonly found in necropsy studies in cats. A clinical diagnosis of pancreatitis is challenging due to nonspecific clinical signs, a lack of diagnostic lipase cutoffs, and frequent presence of multiple diseases. It is still unknown how often pancreatitis alone is found in sick cats and how often clinicopathological evidence of pancreatitis in sick cats does not lead to a clinical diagnosis of pancreatitis. Our aims were to evaluate the extent of comorbidities in cats with suspected pancreatitis, evaluate how often sick cats with hyperlipasemia are diagnosed only with non-pancreatic diseases, and compare their clinical findings. Medical records of 563 client-owned hospitalized cats with available lipase activity measurement (LIPC Roche) > 30 U/L (RI, 6-26) were searched and medical diagnoses recorded and grouped by organ system. Clinicopathological findings were compared between cats with pancreatitis alone (PA), pancreatitis with concurrent disease (PD), and no suspected pancreatitis (NP). We found that PA was present in 33 (6%) cats, 159 cats (28%) were in the PD group, and 371 cats (66%) had no suspected pancreatitis (NP). Clinical, laboratory, and ultrasonographic findings did not differ between PA and PD cats. Lipase activities did not differ between the three groups. The most common disease categories in PD and NP cats were gastrointestinal, hepatobiliary, renal/urinary, and endocrine, and renal/urinary, gastrointestinal, cardiac, and musculoskeletal, respectively. We conclude that cats are rarely hospitalized because of suspected pancreatitis alone, and PA cats did not differ clinically from PD cats. Hyperlipasemia in sick cats without a diagnosis of pancreatitis may be due to a reactive pancreatopathy or preexisting chronic pancreatitis.

Analytical validation of an ELISA for the measurement of feline pancreas-specific lipase and re-evaluation of the reference interval and decision threshold for diagnosing pancreatitis

BACKGROUND

The diagnosis of feline pancreatitis can be challenging. The clinical presentation often includes mild, nonspecific clinical signs, such as vomiting, anorexia, and weight loss. Measurement of feline pancreatic lipase immunoreactivity (fPLI) concentration in serum has been reported to be sensitive and specific for a diagnosis of pancreatitis in cats. However, analytical validation for a widely available commercial assay for the measurement of fPLI concentration has not been published.

OBJECTIVE

We aimed to analytically validate the Spec fPL assay (IDEXX Laboratories, Westbrook, ME), a commercial ELISA for the measurement of fPLI concentration, and re-evaluate its reference interval and decision threshold for diagnosing pancreatitis in cats.

METHODS

Dilutional linearity, accuracy, precision, and the effect of interfering substances were assessed. The upper limit of the reference interval was calculated based on the 95th percentile of results from clinically healthy cats (n = 107), and a decision threshold for diagnosing pancreatitis was calculated with an expected specificity of 99%.

RESULTS

Analytical validation demonstrated good linearity, accuracy, and precision, as well as the absence of interference from lipemia, hemolysis, or icterus. The upper limit of the reference interval for Spec fPL was determined to be 4.4 μg/L, and the decision threshold (a theoretical cut-off) for diagnosing pancreatitis was determined to be 8.8 μg/L based on a desired specificity of 99%.

CONCLUSIONS

The Spec fPL assay is analytically valid, and results suggest that a decision threshold of 8.8 μg/L would have high diagnostic specificity for excluding clinically healthy cats.

Accuracy of acute-phase proteins in identifying lethargic and anorectic cats with increased serum feline pancreatic lipase immunoreactivity

The mainstay of laboratory diagnostics of feline pancreatitis (FP) is measuring serum feline pancreatic lipase immunoreactivity (fPLI). Thus far, several studies have investigated the relationship between acute-phase proteins (APPs) and the presence and severity of FP. Although changes in serum amyloid A (SAA) concentration have been linked with FP, its diagnostic accuracy remains unknown. We aimed to determine the accuracy of selected APPs in identifying cats with a high risk of FP based on increased fPLI. Serum fPLI was measured in cats (n = 52) that were presented to veterinary clinics with signs of lethargy and anorexia. The cats were divided into two groups (fPLI ≤3.5 μg/L; n = 27 and fPLI >3.5 μg/L, n = 25), corresponding to low and high risks of FP. Serum albumin, globulin, haptoglobin (Hp), and SAA concentrations, as well as the albumin-to-globulin ratio (A/G) and SAA-to-albumin (SAA/A) ratios, were determined and compared between groups. The accuracy of these measurements was examined using a multivariable logistic regression model and receiver operator characteristic (ROC) curve analysis. SAA concentrations and SAA/A ratios were significantly (P = .026 and P = .022) higher in cats with increased fPLI, with the area under ROC curve (AUROC) of 68.1% (CI 95%: 53.4%, 82.9%) and 68.6% (CI 95%: 54.0%, 83.2%), respectively. The logistic regression model combining SAA and A/G had AUROC of 75.2% (CI 95%: 62.0%, 88.4%) for identifying cats with increased fPLI. SAA as a sole analyte or combined with A/G had low to moderate accuracy in identifying anorexic, lethargic cats with increased fPLI. Serum albumin, globulin, and Hp concentrations had no discriminatory potential in these cats.

Correlation between metabolomic profile constituents and feline pancreatic lipase immunoreactivity

Background

Feline pancreatic lipase immunoreactivity (fPLI) is commonly used to diagnose pancreatitis in cats (FP). Untargeted metabolomics has been extensively applied in human and veterinary medicine, but no metabolomic studies regarding FP have been conducted.

Objectives

To identify metabolites significantly associated with increased fPLI.

Animals

Forty‐nine client‐owned cats: 11 clinically healthy and 38 with various clinical conditions.

Methods

Analytical cross‐sectional study with convenience sampling. A panel of 630 metabolites belonging to 26 biochemical classes was quantified in plasma using a commercial metabolomic assay. The correlation between plasma metabolite concentrations and serum fPLI was evaluated using Spearman's rank correlation coefficient (R_s) with Bonferroni correction. Multivariable analysis then was performed to control for glomerular filtration rate, liver damage, and blood glucose concentration. The accuracy of selected metabolites in discriminating between cats with normal (≤3.5 μg/L) and increased (>5.3 μg/L) fPLI was estimated using the area under the receiver operating characteristic curve (AUROC).

Results

Four hundred and seven of 630 metabolites (64.6%) were quantified in all cats. When controlled for potential confounders only 3 sphingolipids were significantly positively correlated with fPLI: 2 cerebrosides: HexCer(d18:1/24:0); (R_s = .56), and HexCer(d18:1/24:1); (R_s = .58) and 1 sphingomyelin: SM C18:0 (R_s = .55). Their AUROCs in identifying cats with increased fPLI were 82% (95% confidence interval [CI 95%], 70%‐94%), 84% (CI 95%, 72%‐96%), and 78% (CI 95%, 65%‐92%), respectively.

Conclusions and Clinical Importance

Selected sphingolipids are moderately positively correlated with fPLI and appear to have fair to moderate diagnostic accuracy in discriminating between cats with normal and increased fPLI.

Application of a complete blood count to screening lethargic and anorectic cats for pancreatitis

Background

Feline pancreatitis (FP) is an important health problem of cats. Its diagnostics is based on the combination of quantification of serum pancreatic lipase immunoreactivity (fPLI) and abdominal ultrasonography (AUS). These modalities allow for establishing highly specific diagnosis, however they are relatively expensive and time-consuming. On the other hand, a screening test of high sensitivity which would allow to rule out FP on the first visit without a considerable increase of costs would be clinically useful. To evaluate accuracy of nonspecific inflammatory biomarkers based on complete blood count (CBC) in diagnosing FP 73 client-owned cats with signs of lethargy and reduced appetite lasting for at least 2 days before presentation were enrolled in the cross-sectional study. They were examined with fPLI assay and AUS and classified as cats with very low risk of FP when fPLI ≤3.5 μg/L and AUS negative for FP, or as cats with increased risk of FP in the case of any other combination of results. Then, 7 various CBC measurements were measured in each cat and linked to the risk of FP using the multivariable logistic regression.

Results

Five CBC measurements turned out to be significantly associated with the risk of FP – total leukocyte count (WBC; crude odds ratio(OR_crude) = 12.2; CI 95%: 1.52, 98.5), total neutrophil count (OR_crude = 5.84; CI 95%: 1.22, 27.9), band neutrophil count (BNC; OR_crude = 6.67; CI 95%: 1.98, 22.4), neutrophil-to-lymphocyte ratio (OR_crude = 3.68; CI 95%: 1.25, 10.9), and eosinophil count (EC; OR_crude = 0.34; CI 95%: 0.12, 0.96). The model based on WBC, BNC, and EC proved to have at least fair diagnostic potential (area under ROC curve 82.7%; CI 95%: 72.8%, 92.5%). When WBC <  18 G/L, BNC <  0.27 G/L, and EC >  0.3 G/L was considered as a negative result, and any other combination as the positive result, the CBC model had high sensitivity (91.8%; CI 95%: 80.8%, 96.8%) at a relatively low specificity (58.3%; CI 95%: 38.8%, 75.5%).

Conclusion

The combination of three CBC measurements is an immediately available and fairly accurate screening method for identification of lethargic and anorectic cats with increased risk of FP.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-021-03098-z.