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Testosteronul a crescut globulele roșii la bărbații trans: 38% au depășit pragul masculin de eritrocitoză în 10 ani

Eritrocitoza într-o cohortă mare de bărbați trans care folosesc testosteron: un studiu de urmărire pe termen lung privind prevalența, determinanții și anii de expunere

Studii de cohortă și registreHormoni de sex opus
Authors
Milou Cecilia Madsen, Dennis van Dijk, Chantal M. Wiepjes, Elfi B. Conemans, Abel Thijs, Martin den Heijer
Journal
The Journal of Clinical Endocrinology & Metabolism
Year
2021
Source
https://doi.org/10.1210/clinem/dgab089

Summary

Testosterone makes the body produce more red blood cells. Blood that becomes too thick raises the risk of clots, heart attack and stroke. Amsterdam doctors reviewed blood tests from 1,073 trans men on testosterone over up to 20 years. About one in nine had repeatedly high levels by male standards. The chance of ever crossing the limit kept rising for years, reaching 38% after a decade, so someone stable for years can still develop it. Long-acting injections, smoking, higher weight, older age and lung disease raised the risk. The authors advise checking blood for as long as testosterone is used. More than half of the clinic's trans men were left out for missing data. Using the normal limits for women would label far more people as affected (26%, the authors said in a reply to a letter), so the true scale may be higher.

Key findings

  • Dintre cei 1.073 de bărbați trans care luau testosteron, 11% aveau sânge prea gros (mai mult de jumătate din volumul sângelui format din globule roșii) la două analize după standardele masculine; 3,7% și 0,5% au depășit limite mai mari.
  • 24% au avut cel puțin o analiză de sânge peste limita masculină.
  • În medie, ponderea sângelui formată din globule roșii a crescut de la 39% înainte de tratament la 45% după un an, apoi a crescut doar ușor pe parcursul a 20 de ani.
  • Printre cei 776 de bărbați cu date de început, șansa de a depăși vreodată limita masculină a ajuns la 38% după 10 ani și 50% după 14 ani.
  • Injecțiile cu testosteron cu acțiune prelungită au fost legate de șanse de aproximativ 3 ori mai mari de sânge prea gros comparativ cu gelul; fumatul (șanse de aproximativ două ori mai mari), greutatea mai mare, vârsta mai mare la început și afecțiunile pulmonare au crescut și ele riscul.
  • Folosind în schimb limita normală pentru femei, 26% s-ar fi calificat la două analize, au spus autorii într-un răspuns la o scrisoare publicată.
  • Studiul a măsurat doar analize de sânge, nu evenimente reale de sănătate precum cheaguri de sânge sau infarcte.

Abstract

CONTEXT: Erythrocytosis is a known side effect of testosterone therapy that can increase the risk of thromboembolic events. OBJECTIVES: To study the prevalence and determinants in the development of erythrocytosis in trans men using testosterone. METHODS: A 20-year follow-up study in adult trans men who started testosterone therapy and had monitoring of hematocrit at our center (n = 1073). RESULTS: Erythrocytosis occurred in 11% (hematocrit > 0.50 L/L), 3.7% (hematocrit > 0.52 L/L), and 0.5% (hematocrit > 0.54 L/L) of trans men. Tobacco use (odds ratio [OR] 2.2; 95% CI, 1.6-3.3), long-acting undecanoate injections (OR 2.9; 95% CI, 1.7-5.0), age at initiation of hormone therapy (OR 5.9; 95% CI, 2.8-12.3), body mass index (BMI) (OR 3.7; 95% CI, 2.2-6.2), and pulmonary conditions associated with erythrocytosis and polycythemia vera (OR 2.5; 95% CI, 1.4-4.4) were associated with hematocrit > 0.50 L/L. In the first year of testosterone therapy hematocrit increased most: 0.39 L/L at baseline to 0.45 L/L after 1 year. Although there was only a slight continuation of this increase in the following 20 years, the probability of developing erythrocytosis still increased (10% after 1 year, 38% after 10 years). CONCLUSION: Erythrocytosis occurs in trans men using testosterone. The largest increase in hematocrit was seen in the first year, but also after the first years a substantial number of people present with hematocrit > 0.50 L/L. A reasonable first step in the care for trans men with erythrocytosis while on testosterone is to advise them to quit smoking, to switch to a transdermal administration route, and if BMI is high, to lose weight.

Conclusion

Erythrocytosis occurs in trans men using testosterone. The largest increase in hematocrit was seen in the first year, but also after the first years a substantial number of people present with hematocrit > 0.50 L/L. A reasonable first step in the care for trans men with erythrocytosis while on testosterone is to advise them to quit smoking, to switch to a transdermal administration route, and if BMI is high, to lose weight. The authors add that regular hematocrit control seems warranted for as long as testosterone is used.