OBJECTIVE: To evaluate the use of the acute-phase proteins serum amyloid A (SAA) and haptoglobin as prognostic indicators in horses with colic with regard to the need for surgical intervention, development of complications, and hospitalization cost and duration.
DESIGN: Prospective observational study.
ANIMALS: 20 clinically normal horses and 42 horses with colic.
PROCEDURES: Total WBC and neutrophil counts and plasma fibrinogen, SAA, and haptoglobin concentrations were compared between healthy (control) horses and horses admitted to a veterinary teaching hospital for colic. Clinicopathologic values were compared between medical and surgical colic cases to test the ability of acute-phase proteins to predict indication for surgical intervention, development of complications, and duration and cost of hospitalization.
RESULTS: Mean SAA concentration was significantly higher in the surgical group, compared with that for both the control and medical groups. Haptoglobin concentration did not differ significantly among groups. Horses with colic and an abnormally increased SAA concentration (> 5 μg/mL) were more likely to be managed surgically than medically (OR, 5.7; 95% confidence interval, 1.4 to 22.8). Horses with small intestinal lesions had significantly higher SAA concentrations than did control horses. Euthanasia due to a poor prognosis or the development of thrombophlebitis was more likely for horses with an SAA concentration > 5 μg/mL (OR, 7.6; 95% confidence interval, 1.1 to 52.4). A weak positive correlation (r = 0.30) was observed between cost of treatment and SAA concentration.
CONCLUSIONS AND CLINICAL RELEVANCE: Horses with colic that had an abnormally increased SAA concentration were more likely to require surgical intervention, develop thrombophlebitis, or be euthanized because of a poor prognosis despite treatment.