Abstract
Purpose:
Gender affirmation surgery (GAS) refers to surgical procedures that align physical appearance with gender identity. Data are limited regarding GAS in national cohort studies and we aimed to assess GAS in Danish transgender persons.
Methods:
We conducted a national register-based cohort study in Danish transgender persons. Persons with International Classification of Diseases (ICD)-10 diagnosis code of “gender identity disorder” were included during 2000–2021 and surgical procedure codes were identified up to and including June 2022.
Results:
The cohort included 3812 transgender persons with median age (interquartile range) at study inclusion 19.0 (15.0; 24.0) years for persons assigned female sex at birth (AFAB, N=1993) and 23.0 (19.0; 33.0) years for persons assigned male sex at birth (AMAB, N=1819). The mean (standard deviation) follow-up duration was 4.5 (4.3) years. In persons AFAB, the 5-year cumulative incidence for GAS increased from 14.9 (7.0; 25.6) for persons diagnosed in 2000–2005 to 50.0 (45.9; 53.9) for persons diagnosed in 2014–2018. In persons AMAB, the 5-year cumulative incidence increased from 7.1 (3.5; 12.4) to 17.0 (13.8; 20.4). The mean waiting time from study inclusion to event of any GAS, top surgery or genital surgery, decreased throughout the study period in persons AFAB and persons AMAB. Genital constructive GAS was conducted in 1.4% transgender persons.
Conclusions:
The incidence of GAS increased and waiting time decreased for transgender persons diagnosed during 2000–2018. Genital constructive GAS was rarely performed in Danish transgender persons.
Keywords: gender identity, genital surgery, register based, top surgery, transgender
Introduction
The term transgender describes persons, whose gender identity differs from the assigned sex at birth.1 The proportion of transgender persons is estimated to be 0.6–1.1% in European study populations.2 Gender-affirmation surgery (GAS) refers to surgical procedures that align physical appearance with gender identity.1 GAS is expected to increase health-related quality of life,1,3,4 but national data are sparse regarding GAS in transgender persons.5
Danish transgender care follows international guidelines, and evaluation of transgender persons, including coordinating of GAS, is conducted at three national centers of gender identity (CGI).6 A national guideline in 2015 from the Danish National Board of Health focused on shortened evaluation period and broader access to gender affirming treatment, which has resulted in higher number of annual referrals in the Danish health care system.7 The trend of more annual referrals in Denmark and increasing demand for gender affirming treatment follows the trend of other European countries.7,8 Initiation of gender affirming treatment should be proceeded by individual psychological counseling.1,9
The duration of psychological counseling will vary according to patient needs, but will often be of 6–12-month duration.1,7 GAS should be preceded by a multidisciplinary team conference and gender affirming hormone treatment is most often initiated before GAS.1,9,10 In persons assigned male at birth (AMAB), guidelines recommend that insertion of breast implants should be preceded by 1 to 2 years of stable feminizing hormone treatment to induce and maintain breast development.11 Furthermore, gonadectomy is an irreversible surgical intervention and 1 year of consistent hormone treatment is advised before surgery.1,12
The Danish health care system covers all expenses for GAS conducted at public hospitals. However, Danish legislation only allows GAS after the age of 18 years, whereas the international guideline allows surgical procedures in young persons after informed consent.1 GAS procedures with insertion of breast implants, salpingo-oophorectomy, and orchiectomy are allowed at Danish public hospitals after referral by one of the CGIs.
Mastectomy is allowed at specialized surgical centers affiliated to the national CGIs, whereas only CGI, Rigshospitalet, Copenhagen, is allowed to perform genital constructive GAS. In some cases, GAS can be conducted in transgender persons without referral from a CGI. These cases include insertion of breast implants at private clinics at the patient's own cost, whereas mastectomy outside a specialized hospital unit is not allowed. The increasing number of health care contacts due to gender identity-related diagnoses7,8 could prolong the waiting time for GAS in case of limited surgical capacity.
One previous Danish study investigated GAS conducted in transgender persons at Rigshospitalet, Copenhagen, during 1995–2015 and reported decreasing age at time of surgery from median 40 to 27 years of age through the study period.5 The study did not include data on top GAS conducted at other Danish hospitals than Rigshospitalet, Copenhagen, and only two breast augmentation procedures were included in the dataset of 158 persons (55 transgender females and 103 transgender males).5
The objective of this study was to investigate the prevalence and incidence of GAS in a Danish national setting.
Materials and Methods
The study was designed as a register-based cohort study. In Denmark, all citizens are provided with a unique social security number (central person register, CPR) issued at birth or upon immigration to Denmark. The CPR links data from all Danish health and social care registers at an individual level.13,14 The National Patient Register contains data on all inpatient hospital contacts in Denmark since 1977 and outpatient contacts are included since 1995.15 From 2002, the National Patient Register also includes contacts for private hospitals, excluding private practice specialists and general practitioners. Diagnoses were extracted from psychiatric and somatic parts of the National Patient Register. The Civil Registration System was established in 1968 and included data on death and emigration.14
Ethics
The study design was an open register-based cohort study and no approval was necessary from the local Ethics committee or Institutional Review Board according to Danish law. The study was approved by the Data Protection Agency and Statistics Denmark. Information regarding the study is available with OPEN ID 939: https://open.rsyd.dk/OpenProjects/openProject.jsp?openNo=939&lang=da
Study population
We included Danish transgender persons according to national registers. The study cohort included persons 3 years of age or older with International Classification of Diseases (ICD)-10 diagnosis code of transgender during 2000–2021 in the National Patient Register. The diagnosis codes F64–F649 (“transsexual, gender identity disorder”) were used in 2000–201716 and the diagnosis codes DZ768E-DZ768E4 (“contact regarding gender identity condition”) were applied after 2017. The date of study inclusion (index date) was defined as the first date of a transgender diagnosis. Persons should have valid Danish address at the time of inclusion.
Definition of study parameters
Age was calculated at the index date.
Assigned sex at birth was determined as the earliest recorded CPR-encoded sex. Transgender persons were divided into persons AMAB (which would most often be transgender women) and persons assigned female sex at birth (AFAB, which would most often be transgender men). According to Danish law, a citizen can apply for legal sex change after the age of 18 years.
Until 2014, legal sex change could be performed in persons with transgender diagnosis and gonadectomy only. Since September 1st, 2014, legal sex change is allowed, independent of contact to the health care system. Misclassification of sex at birth could occur if a person immigrated to Denmark after sex change abroad. Furthermore, misclassification might occur if an individual received a transgender diagnosis or had legal sex change performed before year 2000. In accordance, persons with surgical codes of salpingo-oophorectomy and/or hysterectomy were defined as AFAB, and persons with diagnosis codes of penis amputation and/or orchiectomy were defined as AMAB, which resulted in correction of birth assigned sex in five individuals (Fig. 1).
FIG. 1.
Flowchart of study cohort. ¤Persons with surgical codes of salpingo-oophorectomy and/or hysterectomy were defined as AFAB, persons with diagnosis codes of penis amputation and/or orchiectomy were defined as AMAB. AFAB, assigned female at birth; AMAB, assigned male at birth; ICD-10, The international statistical classification of diseases.
Personal income was extracted from the Income Statistics Register17 at the index date and included information on the available average income after tax and interest (included salary, retirement benefits, welfare payment, remuneration, company profits, etc.). The income was categorized into tertiles (high, middle, and low) and persons <18 years of age (no expected income).
Presence of medical morbidity (defined as Charlson comorbidity index ≥1) was defined from hospital diagnoses within 5 years before the index date. The Charlson comorbidity index is based on 19 medical conditions.18 We calculated from the ICD-10 operationalization by Quan et al.19 using the updated weights from Quan et al.20
The event of GAS was defined as surgical procedure code for top or genital surgery in the period from January 1st 2000 to June 2022 following the index date. We also extracted surgical codes for chondrolangyngoplasty and liposuction and presented these data separately. According to Danish legislation, GAS could only occur after the age of 18 years.
To investigate calendar time trends, the transgender cohort was split into subcohorts according to index date: 2000–2005, 2006–2009, 2010–2013, 2014–2018, and 2019–2021.
Statistical analyses
Baseline characteristics in transgender persons were presented as frequencies for categorical variables. Danish legislation on register data does not allow presentation of data from individual persons or groups ≤3 persons to secure anonymity. Therefore, in most analyses, presentation of medians and quartiles was not possible. Instead, continuous variables were summarized as mean standard derivation (SD) values.
When estimating the incidence of GAS, persons were considered at risk (risk time) from the index date or from the date of turning 18 years, if they had an incident diagnosis before the age of 18 years, which allowed to adjust for delayed entry. The study population was followed until first occurrence of surgical procedure, death, emigration, or end of study (June, 2022). Crude surgery rates were estimated as the number of events per person-time, calculating confidence intervals in the Poisson model. The cumulative 5-year incidence was estimated by the Aalen-Johansen estimator, treating death as a competing risk.
Data management and data analyses were conducted using Stata 16 (StataCorp. 2019. Stata Statistical Software: Release 16. College Station, TX: StataCorp LLC) through a remote virtual private network (VPN) access to Statistics Denmark with analysts blinded to the personal identities of the study subjects.
Results
A flowchart of the Danish transgender population is shown in Figure 1. The transgender cohort included 3812 individuals, 1993 (52%) were AFAB and 1819 (48%) were AMAB. The median age at the index date was 19.0 (15.0; 24.0) years in AFAB individuals and 23.0 (19.0; 33.0) years in AMAB individuals (Table 1). Medical morbidity (Charlson comorbidity index ≥1) was present at baseline in 4.4% persons AFAB and 4.3% persons AMAB. The number of persons with low tertile income was 30.8% in persons AFAB and 45.7% in persons AMAB. The mean (SD) follow up duration of the study cohort was 4.5 (4.3) years (AFAB 3.6 [3.4] and AMAB 5.3 [4.8] years).
Table 1.
Description of Danish Transgender Cohort at Inclusion (n=3812)
|
Transgender AFAB
|
Transgender AMAB
|
p | |
|---|---|---|---|
| N =1993 | N =1819 | ||
| Baseline | |||
| Age, median (IQR) | 19.0 (15.0; 24.0) | 23.0 (19.0; 33.0) | 0.000 |
| Mean (SD) | 21.2 (9.9) | 27.7 (14.0) | 0.000 |
| Morbidity (yes) | 88 (4.4%) | 78 (4.3%) | 0.847 |
| Income low tertile | 613 (30.8%) | 831 (45.7%) | 0.000 |
| Income middle tertile | 399 (20.0%) | 430 (23.6%) | 0.007 |
Baseline characteristics, including age, morbidity, and personal income at the index date.
Morbidity defined as Charlson comorbidity index ≥1.
Transgender persons divided according to assigned gender at birth.
P-value: Chi test AMAB versus AFAB.
AFAB, assigned female at birth; AMAB, assigned male at birth; IQR, interquartile range; SD, standard derivation.
GAS procedures in the transgender study cohort are presented in Table 2.Top surgery was conducted in 608 individuals (n=503 AFAB and n=105 AMAB), which corresponded to prevalence of 25.2% in AFAB and 5.8% in AMAB. The most common surgical codes were mastectomy in persons AFAB (483 individuals, 24.2%) and breast augmentation in persons AMAB (95 individuals, 5.2%).
Table 2.
Gender Affirming Surgery in Danish Transgender Study Cohort (n=3812)
| |
AFAB N=1993
|
AMAB N=1819
|
|||
|---|---|---|---|---|---|
| Total N a | N (%) | Age Mean (SD) | N (%) | Age Mean (SD) | |
| Top surgery | |||||
| Mastectomia KHAC10, 15, 20 | 488 | 483 (24.2%) | 24.7 (6.9) | 5 (0.3%) | 41.6 (18.9) |
| Breast reduction KHAD20, 25, 30, 35 | 29 | 27 (1.4%) | 25.5 (9.0) | <3 (0.2%) | NR |
| Breast construction KHAE10, 20, 25 | 36 | 33 (1.7%) | 25.5 (8.1) | 3 (0.2%) | 43.3 (9.6) |
| Breast construction KHAD99, KHAE99 | 26 | 26 (1.3%) | 26.2 (8.8) | . | . |
| Breast augmentation KHAD00,10,50,55,60 | <100 | <3 | NR | 95 (5.2%) | 36.3 (15.1) |
| Breast construction KHAE00 | 4 | . | . | 4 (0.2%) | 34.0 (13.9) |
| Total top surgery | 608 | 503 (25.2%) | 24.7 (6.9) | 105 (5.8%) | 36.4 (14.8) |
| Salpingo-oophorectomy KLAF 01, 10, 11 | 145 | 145 (7.3%) | 30.0 (9.9) | . | . |
| Hysterectomy KLCD00, 01, 01A, 01B, 04, 11 | 148 | 148 (7.4%) | 29.7 (8.7) | . | . |
| Colpectomy KLED00 | 35 | 35 (1.4%) | 30.4 (8.0) | . | . |
| Testis prosthetic KKFH50 | 7 | 7 (0.4%) | 31.6 (5.3) | . | . |
| Penis construction KKGH96, 96C | 17 | 17 (0.9%) | 30.0 (7.4) | . | . |
| Orchiectomy KKFC00, 10 | 65 | . | . | 65 (3.6%) | 41.7 (13.8) |
| Scrotal surgery KKFH96 | 4 | 4 (0.2%) | 30.8 (8.8) | . | . |
| Penis amputation KKGC10 | 40 | . | . | 40 (2.2%) | 42.0 (13.2) |
| Vagina construction KLEE40 | 38 | . | . | 38 (2.1%) | 42.3 (13.1) |
| Vulva construction KLFE10, 96 | <3 | <3 | NR | <3 | NR |
| Total bottom surgery | 234 | 157 (7.9%) | 30.1 (9.8) | 77 (4.2%) | 42.6 (13.7) |
| Chondrolaryngoplasty KDQD40 | <50 | <3 | NR | 47 (2.6%) | 31.1 (10.9) |
| Liposuction truncus KQBJ00 | 32 | 27 (1.4%) | 28.9 (8.2) | 5 (0.3%) | 34.2 (8.9) |
| Total gender affirming surgery | 752 | 556 (27.8%) | 25.5 (7.9) | 198 (10.9%) | 37.1 (14.5) |
NR (N≤3 in cohort).
Gender affirming surgery in transgender CGI cohort during follow up.
Surgery restricted to age ≥18 years according to Danish legislation
An individual may contribute to multiple rows in the table.
Age refers to age at surgery.
Exact total N and exact row percentage cannot be calculated due to discretized values ≤5. In these cases, the discretized value has been set to the value zero.
CGI, centers of gender identity; NR, not reported.
Genital surgery was performed in 234 persons (n=157 AFAB and n=77 AMAB), which corresponded to prevalence of 7.9% (157/1993) in persons AFAB and 4.2% (77/1819) in persons AMAB. In persons AFAB, hysterectomy was conducted in 148 (7.4%) and penis construction was performed in 17 (0.9%) persons. In persons AMAB, orchiectomy was the most prevalent surgical procedure (65 individuals, 3.6%), whereas vagina construction was performed in 38 (2.1%) persons.
Other GAS procedures included chondrolaryngoplasty in persons AMAB (47/1819=2.6%), and in the whole study cohort, liposuction of truncus was performed in 32/3812=0.8%.
Table 3 shows the incidence of GAS in the study cohort. Both the incidence rates (rate per 100 person years) and the 5-year cumulative incidence increased for transgender persons diagnosed from 2000 to 2018. The mean waiting time for GAS and mean age at surgery decreased throughout the study period. Higher cumulative incidence of GAS according to more recent index date is shown in Figures 2 and 3. Same tendencies were found when we studied top and genital surgery in transgender persons AFAB and AMAB separately, Tables 4 and 5.
Table 3.
Gender Affirming Surgery in Danish Transgender Persons (n=3812)
| Person-years | Risk time Mean (SD) | Events | Waiting time for event of surgery Mean (SD) | Age at surgery Mean (SD) | Rate per 100 person years (95% CI) | 5-Year cumulative incidence (95% CI) | |
|---|---|---|---|---|---|---|---|
| AFAB N=2511 |
|||||||
| 2000–2005 | 703.1 | 11.9 (6.5) | 28 | 8.3 (5.1) | 35.1 (9.4) | 4.0 (2.8; 5.8) | 14.9 (7.0; 25.6) |
| 2006–2009 | 540.3 | 8.6 (5.3) | 33 | 5.6 (4.0) | 31.7 (12.8) | 6.1 (4.3; 8.6) | 29.9 (19.0; 41.6) |
| 2010–2013 | 1059.3 | 6.2 (3.6) | 87 | 3.7 (2.5) | 25.6 (7.8) | 8.2 (6.7; 10.1) | 33.6 (26.3; 41.0) |
| 2014–2018 | 2524.7 | 3.6 (2.0) | 334 | 2.6 (1.3) | 24.0 (6.3) | 13.2 (11.9; 14.7) | 50.0 (45.9; 53.9) |
| 2019–2021 | 1017.2 | 1.6 (0.8) | 74 | 1.7 (0.5) | 25.5 (7.3) | 7.3 (5.8; 9.1) | NA |
| AMAB N=2423 |
|||||||
| 2000–2005 | 2046.6 | 14.9 (6.5) | 17 | 8.7 (6.3) | 48.2 (17.7) | 0.8 (0.5; 1.3) | 7.1 (3.5; 12.4) |
| 2006–2009 | 1249.5 | 11.8 (4.2) | 17 | 7.9 (3.9) | 44.0 (14.4) | 1.4 (0.9; 2.2) | 2.1 (0.4; 6.5) |
| 2010–2013 | 1500.5 | 8.6 (2.8) | 37 | 6.9 (2.6) | 42.4 (15.7) | 2.5 (1.8; 3.4) | 7.3 (4.0; 12.0) |
| 2014–2018 | 2878.1 | 4.8 (1.7) | 106 | 3.5 (1.5) | 33.1 (12.2) | 3.7 (3.0; 4.5) | 17.0 (13.8; 20.4) |
| 2019–2021 | 1168.4 | 1.7 (0.9) | 19 | 1.9 (0.9) | 32.7 (11.7) | 1.6 (1.0; 2.6) | NA |
Incidence rates of gender affirming surgery after study inclusion.
CI, confidence interval; NA, not applicable.
FIG. 2.
Cumulative incidence of any gender affirming surgery in transgender cohort. Estimated cumulative incidence of gender affirming surgery in transgender persons split according to index date: 2000–2005, 2006–2009, 2010–2013, 2014–2018, and 2018–2021. Note that Figure 3 is a zoom version of Figure 2.
FIG. 3.
Cumulative incidence of any gender affirming surgery in transgender cohort. Estimated cumulative incidence of gender affirming surgery in transgender persons split according to index date: 2000–2005, 2006–2009, 2010–2013, 2014–2018, and 2018–2021. Zoom version of Figure 2.
Table 4.
Gender Affirming Top Surgery in Danish Transgender Persons (n=3812)
| Person-years | Risk time Mean (SD) | Events | Waiting time for event of surgery Mean (SD) | Age at surgery Mean (SD) | Rate per 100 person years (95% CI) | 5-Year cumulative incidence (95% CI) | |
|---|---|---|---|---|---|---|---|
| AFAB N=2511 |
|||||||
| 2000–2005 | 812.9 | 13.8 (6.6) | 17 | 7.9 (5.9) | 34.2 (10.3) | 2.1 (1.3; 3.4) | 11.1 (4.5; 21.0) |
| 2006–2009 | 588.3 | 9.3 (5.3) | 25 | 5.1 (3.9) | 29.4 (8.3) | 4.3 (2.9; 6.3) | 26.5 (16.2; 37.9) |
| 2010–2013 | 1113.3 | 6.5 (3.6) | 75 | 3.4 (2.4) | 25.2 (7.9) | 6.7 (5.4; 8.5) | 30.6 (23.5; 37.9) |
| 2014–2018 | 2592.7 | 3.7 (2.0) | 315 | 2.6 (1.3) | 23.5 (5.6) | 12.2 (10.9; 13.6) | 47.2 (43.2; 51.2) |
| 2019–2021 | 1020.0 | 1.6 (0.8) | 71 | 1.7 (0.5) | 25.4 (7.4) | 7.0 (5.5; 8.8) | NR |
| AMAB N=2423 |
|||||||
| 2000–2005 | 2157.7 | 15.7 (6.2) | 8 | 2157.70 | 53.5 (21.9) | 0.4 (0.2; 0.7) | NR |
| 2006–2009 | 1293.6 | 12.2 (3.9) | 10 | 1293.56 | 41.5 (17.0) | 0.8 (0.4; 1.4) | NR |
| 2010–2013 | 1551.2 | 8.9 (2.8) | 21 | 1551.15 | 39.0 (14.0) | 1.4 (0.9; 2.1) | 7.3 (4.0; 12.0) |
| 2014–2018 | 2982.6 | 5.0 (1.6) | 62 | 2982.61 | 32.9 (12.3) | 2.1 (1.6; 2.7) | 9.1 (6.7; 11.8) |
| 2019–2021 | 1181.8 | 1.8 (0.9) | 4 | 1,181.75 | 28.5 (5.1) | 0.3 (0.1; 0.9) | NR |
Incidence rates of gender affirming surgery after study inclusion.
Table 5.
Gender Affirming Genital Surgery in Danish Transgender Persons (n=3812)
| Person-years | Risk time Mean (SD) | Events | Waiting time for event of surgery Mean (SD) | Age at surgery Mean (SD) | Rate per 100 person years (95% CI) | 5-Year cumulative incidence (95% CI) | |
|---|---|---|---|---|---|---|---|
| AFAB N=1993 |
|||||||
| 2000–2005 | 767.7 | 13.0 (6.1) | 20 | 7.7 (3.5) | 35.0 (8.3) | 2.6 (1.7; 4.0) | 11.1 (4.5; 21.1) |
| 2006–2009 | 663.7 | 10.5 (4.7) | 21 | 6.7 (3.0) | 34.4 (14.0) | 3.2 (2.1; 4.9) | 12.9 (6.0; 22.5) |
| 2010–2013 | 1308.4 | 7.6 (2.9) | 50 | 5.0 (2.3) | 28.6 (9.0) | 3.8 (2.9; 5.0) | 13.0 (8.3; 18.6) |
| 2014–2018 | 3193.7 | 4.5 (1.9) | 63 | 3.5 (1.4) | 28.5 (8.7) | 2.0 (1.5; 2.5) | 8.0 (6.0; 10.4) |
| 2019–2021 | 1069.9 | 1.7 (0.9) | 3 | 1.2 (0.5) | 26.7 (4.0) | 0.3 (0.1; 0.9) | NR |
| AMAB N=1819 |
|||||||
| 2000–2005 | 2145.0 | 15.7 (6.1) | 6 | 10.3 (6.1) | 44.7 (14.2) | 0.3 (0.1; 0.6) | NR |
| 2006–2009 | 1292.6 | 12.2 (4.0) | 9 | 8.1 (3.4) | 45.4 (12.4) | 0.7(0.4; 1.3) | NR |
| 2010–2013 | 1565.7 | 8.9 (2.7) | 18 | 7.1 (2.4) | 47.4 (16.1) | 1.2 (0.7; 1.8) | 7.3 (4.0; 12.0) |
| 2014–2018 | 3039.5 | 5.1 (1.6) | 37 | 4.2 (1.6) | 40.2 (12.3) | 1.2 (0.9; 1.7) | 5.6 (3.8; 7.8) |
| 2019–2021 | 1177.7 | 1.8 (0.9) | 7 | 1.9 (0.9) | 37.4 (14.8) | 0.6 (0.3; 1.3) | NR |
Incidence rates of gender affirming surgery after study inclusion.
Discussion
In this register-based study, we investigated GAS in Danish transgender persons. This dataset was unique as we could access GAS in an unselected national study cohort of transgender persons. We described increasing incidence of GAS from year 2000 to 2018, shorter waiting time for surgery, and decreased mean age for surgery throughout the study period. Mastectomy was the most common GAS procedure and was conducted in 24% persons AFAB, whereas the prevalence of other surgical procedures was less than 10%. Of special note, the prevalence of genital constructive GAS was only 0.9% in persons AFAB (penis construction) and 2.1% in transgender persons AMAB (vagina construction).
Our dataset included 3812 transgender persons from a Danish population of 5,900,000 individuals (0.06%), which is considerably lower than the reported prevalence of transgender identity of 1%.2 However, only a subset of transgender persons will aim for gender affirming treatment. In comparison, a Swedish register study from 2015 included 2679 transgender persons from a population of 9,747,324 persons (0.03%),3 and the Amsterdam transgender cohort included 8831 transgender persons from a population of 17,530,000 persons (0.05%).21
The mean follow-up duration was 4.5 years and limited follow-up duration would affect our study results, especially regarding genital GAS. Genital GAS is an irreversible surgical intervention and usually requires at least 12 months of hormone treatment and comprehensive multidisciplinary counseling before the patient is placed on waiting list for surgery.1,12 Furthermore, genital constructive GAS is performed at one Danish surgical center, only. Limited capacity at this center would result in longer waiting time for genital GAS. Despite these reservations, our data showed similar pattern for top and genital GAS regarding shorter waiting time and lower age at surgery.
These data confirm and expand findings by Aydin et al.,5 who showed improved access to GAS in Danish transgender persons until 2015 at Rigshopsitalet, Copenhagen. These data confirm that the trend for decreased waiting time for GAS continues, despite increasing demand for transgender care. However, these data will not reflect possible consequences of the covid pandemic taking place from 2020 to 2022, where the capacity of elective surgical procedures was reduced to a minimum.22 Our data showed low number of genital constructive GAS in Danish transgender persons, whereas salpingo-oophorectomy and hysterectomy were performed in 145 and 148 persons, respectively.
Our finding of limited prevalence of lower constructive surgery contrasts findings from other European study centers.2 The number of GAS will reflect national legislation and differences in organization of the national health care system. The Amsterdam group described >74% prevalence of gonadectomy within 5 years of starting gender affirming hormone treatment2 and a Swedish register-based study found that 20.0% transgender persons had surgery of reproductive organs during follow-up.3 Isolated orchiectomy without genital constructive surgery was not an option, until recently, in Denmark, and long waiting list for genital GAS in transgender women will result in prolonged antiandrogen gender affirming hormone treatment.
As recently reported, cyproterone acetate is the most commonly prescribed androgen blocker in Denmark9 and in most European countries.8 In the Nordic countries, cyproterone acetate is prescribed in >40% transgender women, whereas <10% are treated with spironolactone.6 Cyproterone acetate is a synthetic progesterone (progestin) drug with stimulatory effects on the progesterone receptor, which blocks the gonadal axis and potentially improves breast development.8
However, cyproterone acetate is associated with possible serious side effects, such as meningioma.10 Furthermore, progesterone can promote vasoconstriction, inflammation, and fluid retention,23 and use of cyproterone acetate is associated with increased risk of thromboembolism, hypertension, and hyperprolactinemia.24,25 We plan to investigate the impact of long treatment duration of cyproterone acetate and risk of side effects in this study cohort in the context of limited number of performed genital GAS in Denmark.
The AFAB/AMAB ratio for GAS was 2.8 in this study cohort, which was higher than the ratio of 1.9 previously reported by Aydin.5 However, we included nationwide data on top surgery, whereas the study by Aydin only included data from Rigshospitalet, Copenhagen. Mastectomia can be performed outside Rigshospitalet, which could explain our finding of higher rate of national surgical procedures in persons AFAB. Our finding of higher number of GAS in persons AFAB compared to AMAB persons seemed to contrast that the ratio of persons seeking gender affirming medical care is around 1.7 In accordance, the ratio of prescription of masculinizing/feminizing treatment was around 1 in the Danish study cohort.9 Our data support that GAS is especially requested by persons AFAB. In accordance, chest dysphoria is well described in transgender men,26 and chest dysphoria is not expected to be relieved by masculinizing hormone treatment.26
In contrast, feminizing hormone treatment stimulates breast development, however, not in all cases resulting in the desired Tanner stage.11 Local health guidelines may vary regarding referral to top GAS in the public health care system. Top GAS without gender affirming hormone treatment is not usually performed according to Danish guidelines, whereas this procedure may be possible in other countries.2 Accordingly, more nonbinary persons without wish for gender affirming hormone treatment could be included in other study cohorts compared to the Danish dataset.2 In accordance, a Dutch study reported decreasing incidence rate of GAHT, which could reflect referral of persons with other forms of gender dysphoria, where GAHT is not requested.2
We recently reported high risk of lower socioeconomic status in Danish transgender persons compared to age-matched controls,27 with relative risk ratio of 4.4 for being unemployed or on welfare versus employed in transgender persons. Furthermore, we found significantly higher OR for mental health disorders in Danish transgender persons compared to controls, which remained elevated throughout follow-up, especially in transgender persons AMAB.28 GAS was associated with reduced mental health treatment in a Swedish study cohort,3 but we did not have power to investigate changes in mental health after GAS in Danish transgender persons.28 GAS is expected to have a positive effect on gender dysphoria,1,29 which makes limited access to GAS a concern regarding mental health in transgender persons.
Strengths and limitations
Strengths and limitations apply to this study. Access to nationwide data is an important study strength. Furthermore, we had access to all data on genital GAS procedures, as these procedures were only performed at public hospitals in persons with ICD-10 diagnosis code of transgender. However, some limitations may apply to this study. GAS is allowed after the age of 18 years only, whereas initial evaluation and gender affirming hormone therapy can be initiated before the age of 18 years. Therefore, we defined that risk time for GAS started after the age of 18 years and adjusted for delayed entry in survival analyses.
However, inclusion of young persons in the dataset could result in shorter waiting time for GAS. Danish legislation regarding allowed age for GAS was unchanged during the study period. We obtained transgender diagnosis by available ICD-10 codes and transgender persons without hospital contact would not be included in the data set. Furthermore, persons who terminated transgender care before year 2000 were not included. This dataset did not allow evaluation of GAS conducted abroad. Insertion of breast implants is possible at Danish private clinics, and some surgical breast augmentation procedures will be left outside the dataset. Nonbinary persons with wish for gender affirming care would be included in the dataset, but the study cohort represents a selected group of transgender individuals aiming for transgender care.
We divided persons according to assigned sex at birth, which could lead to misclassification of sex in foreigners if they immigrated to Denmark after the date of the legal sex change. Therefore, persons with GAS codes of salpingo-oophorectomy and/or hysterectomy were defined as AFAB and persons with GAS codes of penis amputation and/or orchiectomy were defined as AMAB. However, due to this study design, self-identified gender was more likely to be correctly defined in individuals, who entered the study cohort early. Limited follow-up duration, especially for persons included late in the study period, may have affected our findings, resulting in decreased incidence rates for persons who initiated transgender care in 2019–2021.
Transgender care is a rapidly developing field and we evaluated time trends of GAS by dividing the study cohort into five groups according to the date of study inclusion. The size of the dataset only allowed us to investigate trends in relatively broad time intervals, which could be considered a study limitation. Furthermore, future studies should investigate possible mediators for GAS in transgender persons, including socioeconomic status.
Conclusion
In this study, we showed increasing incidence of GAS in Denmark from year 2000 and onward. Future studies should investigate the impact of limited number of performed genital GAS on psychological and somatic health outcomes.
Abbreviations Used
- AFAB
assigned female sex at birth
- AMAB
assigned male sex at birth
- CGI
centers of gender identity
- CPR
central person register
- GAS
gender-affirmation surgery
- ICD-10
International Classification of Diseases-10
- IQR
interquartile range
- NR
not reported
- SD
standard derivation
Authors' Contributions
D.G. and M.S.A.: Idea, design, and writing manuscript. K.H.R.: Design and criticism of article. T.G.P.: Design, data analysis, and writing article. Ø.L., G.T'S., M.H., M-.L.J.Ø.L.: Idea and criticism of article.
Author Disclosure Statement
No competing financial interests exist.
Funding Information
The study was funded by the collaboration fund between Odense University Hospital and Rigshospitalet, 2019. Region of Southern Denmark.
Cite this article as: Glintborg D, Petersen TG, Rubin KH, Lidegaard Ø, T'Sjoen G, Larsen M-LJØ, Hilden M, Andersen MS (2024) Gender-affirmation surgery in Denmark: a nationwide register-based cohort study, Transgender Health 10:3, 269–278, DOI: 10.1089/trgh.2023.0044.
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