Aging Hemostasis: Changes to Laboratory Markers of Hemostasis As We Age—A Narrative Review

The incidence of venous thromboembolism (VTE) is well recognized to increase with aging. Concurrently, the plasma concentrations of many coagulation factors (e.g., fibrinogen, factor [F] V, FVII, FVIII, and FIX) increase with aging, as does von Willebrand factor (VWF), thrombin generation, and platelet activation. Data are conflicting regarding age-related changes in the natural anticoagulants, including protein C, protein S, and antithrombin. Changes are also observed with components of the fibrinolytic pathway. All in all, aging is associated with a variety of hemostasis changes that on balance reflects a heightened procoagulant status compared with earlier age. It has to be recognized that as this occurs in the otherwise normal general population, this can also be considered a normal phenomenon of progressive life. An element of this heightened procoagulant status may reflect ongoing inflammatory processes, given some markers, notably FVIII and fibrinogen, are acute phase reactants. A variety of acquired prothrombotic risk factors (e.g., cancer, autoimmune disorders, and diabetes) also gradually develop with aging, some of which may induce profound abnormalities of hemostasis, and confound the age-related changes in hemostasis, as well as their influence on thrombotic risk. In this article, we review the changes in hemostasis markers measurable within many hemostasis laboratories, and consider many of the important implications for clinical and laboratory practice. Apart from representing an increased thrombotic risk, additional considerations entail the potential need (1) to utilize age-adjusted normal ranges (e.g., for D-dimer), (2) to consider the consequence on previous diagnoses (e.g., "mild type 1" von Willebrand disease [VWD], where VWF test results may "normalize" with aging), and (3) to consider the effect of these changes of risk factors on the (perceived) therapeutic efficacy of antithrombotic medications such as aspirin.