Summary
Researchers used Kaiser Permanente health records to follow about 5,000 trans adults and nearly 100,000 matched non-trans men and women. They looked at blood clots in the veins, strokes from a blocked blood vessel, and heart attacks. Trans women had clearly more blood clots than either comparison group, and the gap grew over time. In those who started estrogen during the study, clots rose after about 2 years and strokes after about 6 years. Heart attack rates were similar to non-trans men. For trans men there were too few cases to conclude anything. The authors said estrogen raises the risk of clots and probably stroke, and doctors should watch for this long term. The study is large and well matched, but follow-up was short, people were young, and hormone use outside Kaiser was often unknown, so the real risks are probably higher.
Key findings
- شملت الدراسة 2,842 امرأة متحولة و2,118 رجلاً متحولاً، قورنوا بـ 48,686 رجلاً غير متحول و48,775 امرأة غير متحولة من ثلاث مناطق في Kaiser Permanente.
- كان لدى النساء المتحولات 61 جلطة دموية و54 سكتة و33 نوبة قلبية؛ وكان لدى الرجال المتحولين 23 و16 و9.
- مقارنة بالرجال غير المتحولين، كان لدى النساء المتحولات نحو 4 جلطات دموية إضافية لكل 1,000 شخص بعد سنتين ونحو 17 إضافية بعد 8 سنوات؛ ومقارنة بالنساء غير المتحولات، نحو 3 و14 إضافية.
- لدى النساء المتحولات اللواتي بدأن الإستروجين أثناء الدراسة، تقدمت معدلات الجلطات الدموية بعد نحو سنتين ومعدلات السكتة بعد نحو 6 سنوات. وكان هذا متأخراً عما لدى النساء غير المتحولات اللواتي يتناولن العلاج الهرموني البديل بعد سن اليأس.
- كانت النوبات القلبية لدى النساء المتحولات أشيع منها لدى النساء غير المتحولات لكنها مماثلة تقريباً لما لدى الرجال غير المتحولين.
- لم تتوفر بيانات كافية للرجال المتحولين. ولاحظ المؤلفون علامة محتملة لكنها غير مؤكدة جداً على زيادة النوبات القلبية مع التستوستيرون.
- تمت متابعة الناس نحو 4 سنوات فقط في المتوسط، لذا فالمخاطر طويلة الأمد مع تقدمهم في السن ما زالت مجهولة.
Abstract
BACKGROUND: Venous thromboembolism (VTE), ischemic stroke, and myocardial infarction in transgender persons may be related to hormone use. OBJECTIVE: To examine the incidence of these events in a cohort of transgender persons. DESIGN: Electronic medical record-based cohort study of transgender members of integrated health care systems who had an index date (first evidence of transgender status) from 2006 through 2014. Ten male and 10 female cisgender enrollees were matched to each transgender participant by year of birth, race/ethnicity, study site, and index date enrollment. SETTING: Kaiser Permanente in Georgia and northern and southern California. PATIENTS: 2842 transfeminine and 2118 transmasculine members with a mean follow-up of 4.0 and 3.6 years, respectively, matched to 48 686 cisgender men and 48 775 cisgender women. MEASUREMENTS: VTE, ischemic stroke, and myocardial infarction events ascertained from diagnostic codes through the end of 2016 in transgender and reference cohorts. RESULTS: Transfeminine participants had a higher incidence of VTE, with 2- and 8-year risk differences of 4.1 (95% CI, 1.6 to 6.7) and 16.7 (CI, 6.4 to 27.5) per 1000 persons relative to cisgender men and 3.4 (CI, 1.1 to 5.6) and 13.7 (CI, 4.1 to 22.7) relative to cisgender women. The overall analyses for ischemic stroke and myocardial infarction demonstrated similar incidence across groups. More pronounced differences for VTE and ischemic stroke were observed among transfeminine participants who initiated hormone therapy during follow-up. The evidence was insufficient to allow conclusions regarding risk among transmasculine participants. LIMITATION: Inability to determine which transgender members received hormones elsewhere. CONCLUSION: The patterns of increases in VTE and ischemic stroke rates among transfeminine persons are not consistent with those observed in cisgender women. These results may indicate the need for long-term vigilance in identifying vascular side effects of cross-sex estrogen. PRIMARY FUNDING SOURCE: Patient-Centered Outcomes Research Institute and Eunice Kennedy Shriver National Institute of Child Health and Human Development.
Conclusion
The patterns of increases in VTE and ischemic stroke rates among transfeminine persons are not consistent with those observed in cisgender women. These results may indicate the need for long-term vigilance in identifying vascular side effects of cross-sex estrogen. In the discussion the authors state that cross-sex estrogen is a risk factor for VTE and probably ischemic stroke among transfeminine persons, that evidence for transmasculine persons was insufficient (with a possible signal for myocardial infarction), and that the risk must be weighed against the benefits of treatment.