Introduction. Hemarthrosis is a frequent clinical manifestation in patients with hemophilia A (HA). In addition, the course of GA may be accompanied by concomitant diseases. The most effective way to treat hemophilia is replacement hemostatic therapy with coagulation factor VIII (FVIII) drugs. But changes in some parameters of the pharmacokinetics of these drugs against the background of the most common concomitant diseases remain poorly studied.

The aim of this work was to investigate changes in the activity of exogenous FVIII in patients with HA against the background of the most common comorbidities in the population of individuals with hemophilia, taking into account the severity of the joint syndrome according to the joint index (SI).

Materials and methods. The material of the study is the blood of 127 patients with GA, who were divided into three categories – patients with viral hepatitis B and C, urolithiasis, and angina pectoris. FVIII (50 IU/kg) was administered once to all patients for the study of pharmacokinetic parameters (estimated maximum activity of FVIII is 100 IU/dL). FVIII activity (A) was determined by a one-step method. The functional state of the joints was determined using the HJHS joint health score (Hemophilia Joint Health Scores) scale, followed by the calculation of the joint index (SI).

Results. Depletion of FVIII reserves of own synthesis is more pronounced in patients with GA and chronic hepatitis, as well as in groups with high SI values. These changes can be compensated by regular prevention. In angina pectoris, the maximum activity of exogenous FVIII has higher values compared to patients of other categories. This indicates the activation of hemostasis reactions at the expense of the body’s own reserves. Arthrosis, arthritis, and chronic synovitis affect CI indicators. The latter has the most significant contribution. Inflammatory reactions can stimulate the hemostasis system. Significant activation of hemocoagulation is limited by congenital deficiency of F VIII in GA. As a result of inflammation, excessive consumption of self-synthesized FVIII can occur, which accelerates the destruction of joints in GA.

Conclusions. In patients with hemophilia A with a mild course of arthropathy chronic viral hepatitis B or C can reduce the level of maximal activity of factor VIII after its exogenous administration in comparison with the calculated value, as well as with the parameter of maximal activity of patients with other investigated concomitant diseases. In patients with stable angina pectoris of the I and II functional types on the background of coronary heart disease, the increase in the activity of exogenous factor VIII occurs more pronounced than in patients of other categories and compared to the calculated values. The reduction of the activity of factor VIII to the lower limit of values characteristic of a mild form of hemophilia is more delayed and is more than 48 hours. An increase in the severity of the joint syndrome in patients with hemophilia A does not lead to a decrease in the activity of blood coagulation factor VIII as a result of its consumption against the background of a congenital deficiency under the condition of full prevention.

Keywords: hemophilia A, joint syndrome, concomitant diseases, pharmacokinetics of factor VIII.