IM01 - Effect of Corticosteroid Administration on Serum C-reactive Protein Concentrations in healthy Dogs

Abstract: Background: Serum C-reactive protein (CRP) is a biomarker of systemic inflammation in dogs and is used in clinical practice to aid in diagnosing and monitoring primary inflammatory conditions (e.g., immune-mediated polyarthritis). Treatment of these diseases often includes anti-inflammatory or immunosuppressive doses of corticosteroids. However, potential effects of corticosteroid administration on serum CRP concentrations in dogs have not been studied.

Objective: To evaluate serial serum CRP concentrations in healthy dogs receiving high-dose corticosteroid treatment of >4 weeks.

Animals: Samples from a prospective cohort study including 12 healthy Beagle dogs were used.

Methods: Serum samples obtained before initiation (baseline) and on days 1, 5, and 28 of receiving either 8 mg/kg hydrocortisone PO q12h (6 dogs) or placebo (6 control dogs) were used. Serum CRP concentrations were measured in all samples (stored at -80ºC) using the TriDelta canine CRP-ELISA (total of 2 assay runs using the same assay reagents). A MANOVA model with Box-Cox transformed (l = -0.93) data followed by individual t-tests served for statistical analysis, with P < 0.05 indicating significance.

Results: Serum CRP concentrations slightly decreased over the 4 weeks in both groups of dogs, without a significant effect of hydrocortisone administration (P=0.7605; MANOVA). Two baseline samples and one sample obtained on day 1 of hydrocortisone treatment yielded serum CRP concentrations above the upper reference limit ( >7.6 mg/L); all other measurements were within the reference interval.

Conclusions and clinical importance: These findings suggest a lack of a confounding effect of hydrocortisone administration on serum CRP concentrations in dogs.