Serum 25(OH)D reflects clinical characterization in dogs with chronic enteropathies

Introduction: In canine chronic enteropathies (CE) and protein-losing enteropathy (PLE), vitamin D deficiency is recognized as a negative prognostic factor, while 25(OH)D status in relation to other clinical phenotypes has been poorly investigated. Methods: This study aimed to describe differences in CE dogs according to their response to treatment and to reveal potential associations with retrospective clinical and diagnostic data. Results: A total of 91 dogs were obtained from clinical records and categorized based on their response to treatment into the following groups: food- responsive enteropathy (FRE, n = 39), microbiota-related modulation-responsive enteropathies (MrMRE, n = 26), immunosuppressant-responsive enteropathy (IRE, n = 16), and PLE (n = 10). 25(OH)D, determined by UHPLC–MS/MS from stored serum samples, differed significantly among groups (p < 0.001). Median levels were markedly lower in the PLE group (10.3 ng/mL; range 10–27) than in FRE (33 ng/mL; 10–68) and MrMRE (37 ng/mL; 10–61) groups (p < 0.001). IRE group (20 ng/mL; 10–43) also showed reduced concentrations relative to FRE and MrMRE (p = 0.006). A multivariable linear regression model obtained using data from 75/91 dogs, revealed that fructosamine and phosphorus were positively associated with 25(OH)D status, while increased c-reactive protein was associated with a lower 25(OH)D. Conclusion: In CE dogs, 25(OH)D is negatively affected by inflammation and reflects the severity of clinical characteristics and serum protein- related biomarkers