Interleukin-6 as a prognostic marker in dogs in an intensive care unit

Background: Interleukin-6 (IL-6) is involved in the acute phase reaction during inflammatory disease, including septicemia and the inflammatory response syndrome (SIRS). In people, IL-6 has been studied as a prognostic marker in intensive care medicine, where nonsurvivors had significantly higher IL-6 concentrations than survivors.

Objectives: The objective of the study was to investigate the prognostic value of IL-6 in dogs admitted to the intensive care unit based on sensitivity and specificity.

Methods: Dogs suffering from different severe diseases treated in the intensive care unit were divided into 2 groups of survivors and nonsurvivors. Serum IL-6 concentrations were measured with a canine-specific ELISA (enzyme-linked immunosorbent assay) kit.

Results: Sixty-nine dogs were included in the study, including 20 survivors, 9 nonsurvivors, and 40 control dogs. In the control group, IL-6 serum concentrations were below the detection level (0 pg/mL). In the group of nonsurviving dogs, IL-6 ranged from 45-4656 pg/mL (median 1398 pg/mL). The surviving dogs had a range of 0-405 pg/mL (median 84.5 pg/mL). The mean IL-6 concentration was significantly higher (P < .001) in nonsurvivors than in survivors. Using a cutoff of 400 pg/mL, a sensitivity of 90% and specificity of 95% were determined.

Conclusions: The results of this study suggest that IL-6 is a useful prognostic marker for canine critical care patients with acute internal disease.