Comparison of clinical, clinicopathologic, and histologic variables in dogs with chronic inflammatory enteropathy and low or normal serum 25-hydroxycholecalciferol concentrations.

Background The cause of low serum vitamin D concentrations in dogs with chronic inflammatory enteropathy (CIE) is not well understood. Objective Improve understanding of pathogenesis of low serum vitamin D concentrations in dogs with CIE by comparing several clinical, clinicopathologic, and histologic variables between CIE dogs with low and normal serum 25-hydroxyvitamin D concentrations (25[OH]D). Animals Fifteen dogs with CIE and low serum 25[OH]D concentrations; 15 dogs with CIE and normal serum 25(OH)D concentrations. Methods Prospective cohort study. Clinical and clinicopathologic variables were compared between groups. Correlations between serum 25(OH)D concentration and histopathologic variables were assessed. Results Dogs with CIE and low serum 25(OH)D concentrations had higher canine chronic enteropathy clinical activity index scores (P = .003), lower serum alpha-tocopherol (P < .001), cholesterol (P < .001), and albumin (P < .001) concentrations and higher serum C-reactive protein (P = .004) concentrations compared to CIE dogs with normal serum 25(OH)D concentrations. Serum concentrations of vitamin D-binding protein (VDBP) were not different between groups (P = .91). Duodenal morphologic and inflammatory histopathological scores (P = .002 and P = .004, respectively) and total histopathological scores in duodenum and combined duodenum and ileum negatively correlated with serum 25(OH)D concentration. Conclusions and Clinical Importance The pathogenesis of low serum vitamin D concentrations in dogs with CIE is likely multifactorial. Fat malabsorption deserves further study in dogs with low serum vitamin D concentration and CIE. Loss of VDBP does not appear to be an important cause of low serum vitamin D concentration in dogs with CIE.