Recent medical research by Dr. Henk Asscheman of Amsterdam, the Netherlands and his colleagues shows that transition related hormone treatment leads to very few long-term side effects.
Dr. Asscheman's team examined more than 2000 patients from 15 US and European treatment centers (6 US and 9 European) for the study, called Comorbidity and Side Effects of Cross-Sex hormone Treatment in Transsexual Subjects, with at least one year of follow-up on nearly 1600.
Our results are very reassuring. There are mostly minor side effects and no new [adverse events] observed in this large population.
--Dr. Asscheman
Asscheman spoke last week at the Joint Meeting of the International Society of Endocrinolgy and the Endocrine Society (ICE/ENDO) 2014, where he said the data confirmed smaller studies performed over the past decade.
The take-home message is that when using the guidelines from the Endocrine Society (Endocrine Treatment of Transsexual Persons) you are not going to see a lot of comorbidities with cross-sex hormone treatment.
--Dr. Asscheman
The primary serious side effect, venous thromboembolism, which was previously known, occurred in 1% of male-to-female transgender transitions, due to estrogen treatment. This is lower than has been reported in the past.
Previous research by Dr, Asscheman's team centered on venous thromboembolism.
Administration of cross-sex hormones to male-to-female transsexual subjects, usually oestrogens + often anti-androgens, such as cyproterone acetate, carries a risk of venous thromboembolism (VTE). VTE usually occurs in the first year of oestrogen administration. Ethinyl oestradiol, due to its chemical structure, was in 2003 identified as a major factor in the occurrence of VTE. Most clinics do not prescribe ethinyl oestradiol any longer, but people who take hormones without medical supervision use often oral contraceptives containing ethinyl oestradiol, many times in overdose. Cessation of use of ethinyl oestradiol and peri-operative thrombosis prophylaxis for surgery have reduced prevalence rate of VTE. Other oral oestrogens should not be overdosed, and transdermal oestrogen is to be preferred. Thrombosis prophylaxis for surgery is mandatory. It seems advisable to stop hormone use at least 2 weeks before major surgery, to be resumed only after 3 weeks following full mobilisation.
--Link
The 1596 adults who completed the follow-up consisted of 1073 MtF and 523 FtM patients. The mean period of follow-up for the MtF group was 5.6 years. The mean age for that group was 35.0 years. The mean period of follow-up for the FtM group was 4.5 years and the group had a mean age of 27.5 years.
More than 70% of the MtFs received cyproterone acetate (in Europe) or spironolactone (in the US) as an androgen antagonist in addition to the estrogen treatment.
More than 90% of the FtMs received intramuscular or topical testosterone administration.
The most common baseline comorbidity in both groups was depression, occurring in 24.9% in MtF patients and 13.6% of FtM patients. Asscheman noted that the frequency of depression varied greatly with location of the treatment center. After treatment 2.4% of the MtF subjects and 1.4% of the FtM subjects still reported depression.
Dr. Asscheman therefore concluded that...
Sex-reassignment treatment does not cure depression.
Other comorbidities existant before hormonal therapy were Type 2 diabetes (3.2% in MtF / 0,6% in FtM), HIV infection (2.6% / 0.0%), morbid obesity (2.5% / 2.5%), hypothyroidism (2.1% / 2.3%), prostate cancer (0.4% / NA), and testicular carcinoma (0.3% / NA).
The hypothyroidism rate was about twice what Dr. Asscheman expected.
After treatment side effects in MtF subjects included weight gain (0.5%), myocardial infarction (0.4%), and stroke (0.1%). Dr. Asscheman stated that hypertension was common in this group.
The FtM subjects reported acne (2.9%), weight gain (0.4%), muscle pain (0.4%), and liver enzyme abnormalities (0.4%)
Dr. Asscheman noted that the study was limited by the small number of patients followed for over 10 years or of age greater than 60. He also noted some difference in rates between the US and European centers.
Some side effects are expected, such as venous thromboembolism with estrogen use, but most of the results are really reassuring,
One researcher reported having worked for Bayer Schering, Pfizer, Inc, and Ipsen. The other researches reported no possible conflicts of interest.
Our data show a very reassuring picture of side effects with cross-sex hormone treatment. Our observations are biased because we have no data on those who were lost after few visits (lost to follow up) and those who went to other clinics ("shoppers"). Nevertheless our data confirm the reassuring data from studies with smaller numbers published in the last 10 years.
--Abstract