Chronic testosterone administration improves cardiac contractility and has a beneficial effect on the haemostatic system by enhancing fibrinolytic activity and inducing hypocoagulation in healthy rats

Effects of gender affirming hormone therapy with testosterone on coagulation and hematological parameters in transgender people assigned female at birth: A systematic review and meta-analysis

BACKGROUND

Hormone replacement therapy is associated with an increased thromboembolic risk. The effects of testosterone (T) on coagulation markers in people assigned female at birth (AFAB) under gender affirming hormone therapy (GAHT) are not well described.

METHODS

Systematic review and meta-analysis on English-language articles retrieved from PubMed, Scopus and Cochrane Library up to April 2023 investigating T therapy in AFAB people. Coagulation parameters included international normalized ratio (INR), fibrinogen, activated partial thromboplastin clotting time (aPTT), plasminogen activator inhibitor-1 (PAI-1); hematological variables included hemoglobin (Hb) and hematocrit (HCT). We also reported the rate of thromboembolic events. Data were combined as mean differences (MD) with a 95 % confidence interval (CI) of pre- vs post-follow-up values, using random-effects models.

RESULTS

We included 7 studies (6 prospective and 1 retrospective) providing information on 312 subjects (mean age: 23 to 30 years) who underwent GAHT with variable T preparation. T therapy was associated with a significant increase in INR values [MD: 0.02, 95 % confidence interval (CI): 0.01-0.03; p = 0.0001], with negligible heterogeneity (I2 = 4 %). T therapy was associated with increased Hb (MD: 1.48 g/dL, 95%CI: 1.17 to 1.78; I2 = 9 %) and HCT (4.39 %, 95%CI: 3.52 to 5.26; I2 = 23 %) values. No effect on fibrinogen, aPTT and PAI-1 was found. None of the study reported thromboembolic events during the follow-up.

CONCLUSION

Therapy with T increased blood viscosity in AFAB men. A slight increase in INR values was also found, but the clinical relevance and mechanism(s) of this finding needs to be clarified.

Effects of Exogenous Androgens on Platelet Activity and Their Thrombogenic Potential in Supraphysiological Administration: A Literature Review

Anabolic androgenic steroids (AAS), simply called “androgens”, represent the most widespread drugs used to enhance performance and appearance in a sporting environment. High-dosage and/or long-term AAS administration has been associated frequently with significant alterations in the cardiovascular system, some of these with severe endpoints. The induction of a prothrombotic state is probably the most life-threatening consequence, suggested by numerous case reports in AAS-abusing athletes, and by a considerable number of human and animal studies assessing the influence of exogenous androgens on hemostasis. Despite over fifty years of research, data regarding the thrombogenic potential of exogenous androgens are still scarce. The main reason is the limited possibility of conducting human prospective studies. However, human observational studies conducted in athletes or patients, in vitro human studies, and animal experiments have pointed out that androgens in supraphysiological doses induce enhanced platelet activity and thrombopoiesis, leading to increased platelet aggregation. If this tendency overlaps previously existing coagulation and/or fibrinolysis dysfunctions, it may lead to a thrombotic diathesis, which could explain the multitude of thromboembolic events reported in the AAS-abusing population. The influence of androgen excess on the platelet activity and fluid–coagulant balance remains a subject of debate, urging for supplementary studies in order to clarify the effects on hemostasis, and to provide new compelling evidence for their claimed thrombogenic potential.