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Testosterona elevou glóbulos vermelhos em homens trans: 38% passaram do limiar masculino de eritrocitose em 10 anos

Eritrocitose em uma grande coorte de homens trans em uso de testosterona: um estudo de acompanhamento de longo prazo sobre prevalência, determinantes e anos de exposição

Estudos de coorte e registrosHormônios do sexo oposto
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

  • Dos 1.073 homens trans em uso de testosterona, 11% tinham sangue espesso demais (mais da metade do volume do sangue formada por glóbulos vermelhos) em dois exames pelos padrões masculinos; 3,7% e 0,5% ultrapassaram limites mais altos.
  • 24% tiveram pelo menos um exame de sangue acima do limite masculino.
  • Em média, a parcela do sangue formada por glóbulos vermelhos subiu de 39% antes do tratamento para 45% após um ano, e depois subiu apenas ligeiramente ao longo de 20 anos.
  • Entre os 776 homens com dados iniciais, a chance de algum dia passar do limite masculino chegou a 38% após 10 anos e 50% após 14 anos.
  • As injeções de testosterona de ação prolongada foram ligadas a cerca de 3 vezes a chance de sangue espesso demais em comparação com o gel; tabagismo (cerca do dobro da chance), peso maior, idade mais avançada de início e doenças pulmonares também aumentaram o risco.
  • Usando em vez disso o limite normal para mulheres, 26% se qualificariam em dois exames, disseram os autores em uma resposta a uma carta publicada.
  • O estudo mediu apenas exames de sangue, não eventos reais de saúde como coágulos ou infartos.

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.