The Cardiovascular Question That Every Hormone Practitioner Must Answer
Every practitioner who prescribes TRT, HRT, or other hormone therapies will face the cardiovascular question from patients, referring providers, and occasionally from the media. Understanding the actual evidence — including its nuances, limitations, and evolving nature — enables you to provide informed, confident, evidence-based answers and make clinical decisions that appropriately balance benefit and risk.
TRT and Cardiovascular Risk: What the Evidence Shows
The cardiovascular safety of TRT has been debated since a 2010 Testosterone in Older Men with Mobility Limitations (TOM) trial was halted early due to increased cardiovascular events in a frail elderly population. This generated substantial concern. However, the landmark TRAVERSE trial (2023) — a randomized controlled trial of 5,246 middle-aged and older men with hypogonadism and elevated cardiovascular risk — found no significant increase in major cardiovascular events with testosterone therapy compared to placebo. This large, well-designed trial substantially improved the evidence base for TRT safety.
Hematocrit and Thrombosis Risk
TRT raises red blood cell production via erythropoiesis stimulation, increasing hematocrit. Elevated hematocrit (>54%) increases blood viscosity and theoretical thrombotic risk. Management includes dose reduction, dose splitting (more frequent, smaller injections), switching delivery methods, or therapeutic phlebotomy in refractory cases. This is a real clinical consideration that mandates regular CBC monitoring — not a reason to avoid therapy, but a reason to monitor carefully.
Estrogen Therapy and Cardiovascular Risk in Women
The WHI’s original findings on cardiovascular risk were driven largely by the conjugated equine estrogen + medroxyprogesterone acetate arm, with oral administration and older patient populations. Subsequent analyses and prospective trials (KEEPS, ELITE) show that transdermal estradiol plus micronized progesterone, initiated in younger, healthier women during the “timing hypothesis” window (within 10 years of menopause or before age 60), does not increase cardiovascular risk and may be cardioprotective. Route of administration matters significantly — oral estrogen increases CRP and triglycerides; transdermal does not.
Lipid Effects of TRT
TRT can modestly reduce HDL cholesterol and may increase LDL in some patients — effects that vary significantly by delivery method (injections more pronounced than topicals) and dose. Monitor a full lipid panel including ApoB and LDL-P (particle number) rather than relying solely on LDL-C. Cardiovascular benefits from testosterone’s effects on body composition, insulin sensitivity, and inflammation may offset modest lipid changes in many patients.
Patient Risk Stratification
Not all patients carry the same cardiovascular baseline risk. Assess cardiovascular risk at baseline using tools like the ASCVD 10-year risk calculator, ApoB, Lp(a), hsCRP, and functional testing (VO2max, resting heart rate, blood pressure). Patients with high baseline cardiovascular risk require more careful monitoring, conservative dosing, and coordination with cardiology when warranted. The goal is not to avoid therapy but to manage it intelligently.