Evaluation of Coagulation Parameters in Dogs with Overweight or Obesity

Abstract

Background: Hemostatic alterations have already been well characterized in humans with body fat excess, being included in the list of obesity related comorbidities. Overweight and obesity are common in dogs; however, there is little information about the blood coagulation parameters in dogs with these conditions. The aim of this study was to compare hematological and coagulation parameters between lean dogs and overweight or obese dogs, including platelets count; prothrombin time (PT); activated partial thromboplastin time (aPTT), coagulation time (CT) and plasma fibrinogen concentration.

Materials, Methods & Results: A total of 22 dogs (aged 1 to 10 years, neutered) were evaluated, 10 of them presented ideal body condition score (BCS 4-5) and formed the group 1 (control) and 12 were overweight or obese (BCS 7-9) and formed the group 2. The dogs were submitted to clinical evaluation and then to blood collection for the following laboratory tests: blood count (performed on automatic analyzer), quantification of plasma proteins by refractometry, determination PT, aPTT and plasma fibrinogen concentration using specific commercial kits, and CT by Lee-White method. Compared to group 1, group 2 presented a lower leukocytes and lymphocytes counts (P < 0.05) and a higher concentration of plasma fibrinogen (P = 0,026), but compatible with reference values. No difference was observed in the erythrogram, platelets count, total plasma protein concentration, PT, aPTT and CT between the groups. BCS was negatively correlated with leukocytes (r = -0.45) and lymphocytes (r = -0.60) counts and positively with plasma fibrinogen concentration (r = +0.56).

Discussion: The reduction in lymphocytes led to a lower leukocytes count in the dogs of group 2. The migration of peripheral blood lymphocytes to adipose tissue has been reported in the early phase of the inflammatory process induced by obesity and could justify the reduction of circulating lymphocytes in overweight or obese dogs evaluated in this study; however, cytopathological assessment of adipose tissue was not performed. Fibrinogen has to be converted to fibrin for clot formation, so the concentration of this plasma protein is an important parameter for the evaluation of hemostasis. However, there are reports of increase in plasma fibrinogen as a result of infammatory processes. In group 2, formed by dogs with overweight or obese, the higher value of plasm fibrinogen concentration, associated with lower lymphocyte count, may suggest an early-stage inflammatory process. Similar results were described in obese humans, but also evidenced in obese dogs. Supporting this suggestion, the correlation analysis indicates that the higher the body fat excess (estimated by the BCS), the higher the fibrinogen concentration and the lower the lymphocyte count in evaluated dogs. Despite the higher concentration of plasma fibrinogen in group 2, no change was observed in the hemostasis of overweight or obese dogs, due to the normal values for platelets count, PT, aPTT and CT, excluding a hypercoagulability condition as already hypothesized by other authors for dogs and obese humans. The difference between our findings and the literature may be in the time of evolution of the disease, since we evaluated younger dogs. In conclusion, the body fat excess did not alter the erythrogram and the activity of the clotting factors, estimated by PT, aPTT and CT, but it interfered in the leukogram and increased the plasma concentration of fibrinogen in the evaluated dogs.