Clinical Practice Guideline
Quality of Life Following Male-To-Female Sex Reassignment Surgery
; ; ;
Background: The prevalence of persons who are born with primary and secondary male sexual characteristics but feel that they are female (trans women) is ca. 5.48 per 100 000 males in Germany. In this article, we provide a detailed overview of the currently available data on quality of life after male-to-female sex reassignment surgery.
Methods: This review is based on publications retrieved by a systematic literature search that was carried out in the PubMed, EMBASE, Web of Science, and PsycINFO databases in March 2017.
Results: The 13 articles (11 quantitative and 2 mixed quantitative/qualitative studies) that were found to be suitable for inclusion in this review contained information on 1101 study participants. The number of trans women in each study ranged from 3 to 247. Their mean age was 39.9 years (range: 18–76). Seven different questionnaires were used to assess postoperative quality of life. The findings of the studies permit the conclusion that sex reassignment surgery beneficially affects emotional well-being, sexuality, and quality of life in general. In other categories (e.g., “freedom from pain”, “fitness”, and “energy”), some of the studies revealed worsening after the operation. All of the studies were judged to be at moderate to high risk of bias. The drop-out rates, insofar as they were given, ranged from 12% to 77% (median: 56%).
Conclusion: Current studies indicate that quality of life improves after sex reassignment surgery. The available studies are heterogeneous in design. In the future, prospective studies with standardized methods of assessing quality of life and with longer follow-up times would be desirable.
The term “gender incongruence” (GI) describes the situation in which a person does not identify with the gender they were assigned at birth on the basis of physical sexual characteristics and that they consequently experience “a marked and persistent incongruence between . . . experienced gender and the assigned sex” (1). The term trans women describes persons with congenital primary and secondary male sexual characteristics (assigned male at birth) who feel/identify as women. Trans men are persons who feel/identify as men but who have primary and secondary female sexual characteristics (assigned female at birth). Persons who fully identify with the sex/gender they were assigned at birth are known as cis women and cis men.
A data analysis from 2000 showed a prevalence in Germany of 4.26 trans persons/100 000 population (5.48 trans women/100 000 of the male population and 3.12 trans men/100 000 of the female population) (2). We are not aware of any more recent data for Germany.
If persons with gender incongruence develop clinically relevant biopsychosocial suffering, they have gender dysphoria (GD), according to the DSM-5 classification (3). For many trans persons, physical transition is the best option for alleviating the symptoms of gender dysphoria (4). Sex/gender reassignment hormone treatment as well as surgery have a central role in this setting (5). The latter comprise surgical procedures involving the genitals (sex reassignment surgery) (Box), the breasts, and the face and vocal cords, as well as hair epilation (6).
A US study showed that from 2000 to 2011, the rate of surgical sex reassignment measures among trans persons rose from 72% to 83.9% (7). These data move the question of the effectiveness of such operations increasingly into the focus of clinical attention and awareness (8–11).
In the context of evidence-based medicine, the consensus is now that the success of medical procedures should not be studied merely in terms of objective results (survival and complication rates, measurements of functionality, etc), but that patients’ personal wellbeing should be included in assessing the success of any procedure (12, 13). Review articles to date have shown that sex reassignment hormone treatment has a positive effect on the quality of life of trans persons (14, 15). By contrast, an overall assessment of quality of life after sex reassignment surgery is so far lacking. In this article we will attempt to provide a review of current studies, and on this basis we will investigate the question of quality of life after sex reassignment surgery.
For the review to be as representative as possible, this article deals with trans women only, whose incidence is notably higher than that of trans men (0.41 male to female/100 000 total male population in Germany and 0.26 female to male/100 000 total female population in Germany) (2).
We conducted as systematic literature search in PubMed, EMBASE, Web of Science, and PsycINFO in March 2017. GW and DGN independently undertook the article search on the basis of the recommendations summarized in the PRISMA statement (16). Details of the methods are described in the eMethods section.
We included only articles on the subject of the quality of life of trans women after sex reassignment surgery. GW, RF, and DGN operationalized (eTable 1) the search terms in an iterative process according to the PICO method (e1) and set out a search string (eTable 2).
Among others, we excluded studies that did not focus exclusively on trans persons or that didn’t collect data on quality of life by using a standardized questionnaire. We also excluded studies in underage trans people.
The Figure shows the study selection process.
All included articles are non-randomized studies with an evidence level of III (e2). In the case of studies that reported on the quality of life of trans women as well as trans men (17–21) we ensured that the data for trans women were evaluated separately or that the ratio of M–F/F–M favored trans women. Table 1 shows further key study data; Table 2 shows the quality characteristics of the studies.
The studies made use of the following instruments:
- 6 studies used the Short Form 36 Health Survey (SF-36) (18, 20, 22–25);
- 2 studies used the World Health Organization’s Quality of Life 100 questionnaire (WHOQOL-100) (17, 26);
- 2 studies used the Subjective Happiness Scale (SHS) in combination with the Satisfaction with Life Scale (SWLS) and the Cantrils Ladder of Life Scale (CLLS) (27, 28);
- 2 studies used the FLZ questionnaire (Fragebogen zur Lebenszufriedenheit) (21, 29); and
- 1 study used the King’s Health Questionnaire (KHQ) (19).
None of the questionnaires constitutes an investigative tool that is specifically tailored to trans persons. Table 3 shows the result scales. Table 2 shows the confounding variables and, as far as it is possible to assess this, the risk of bias.
Quality of life
The SF-36 and WHOQOL-100 are validated, reliable and disease–non-specific instruments for measuring health-related quality of life (30, 31). They can be used to gain information on the individual health status and allow for observing disease-related stresses over time. The questionnaires collect data on numerous aspects of daily life, which in their totality reflect quality of life. They are used internationally and therefore make cross-cultural studies an option (32).
Studies that used the SF-36 to answer the question of postoperative quality of life (18, 20, 22–25) observed after sex reassignment surgery an improvement in “social functioning”, “physical” and “emotional role functioning”, “general health perceptions”, “vitality”, and “mental health” (p = 0.025 to p >0.05). In two of these studies (22, 24), “mental health” in trans women after sex reassignment surgery did not differ significantly from the standard sample. This explains the formally non-significant result. Ainsworth and Spiegel (22) showed that trans women without surgical intervention when compared indirectly with cis women from the SF-36 standard sample reported significantly poorer “mental health” (39.5 vs 48.9; p <0.05). Lindqvist et al. (23) and Weyers et al. (24) found an improvement in “self-perceived health” in the first postoperative year (p <0.05 and p <0.009), which deteriorated later but did not fall as low as its original score (p <0.0001). Furthermore, the studies concluded that “physical pain” increased postoperatively and “physical functioning” decreased; the postoperative follow-up periods varied between 3 months (18) and 5 years (23). According to Lindqvist et al. (23), “physical pain” in trans women five years postoperatively was comparable to that in the standard population (72.5 vs 72.7; SD 26.5).
Studies that used the WHOQOL-100 came up with the following results: Cardoso da Silva et al. (26) observed postoperatively an increase in “sexual activity” (p = 0.000) compared with the preoperative evaluation (prospective study design). Furthermore they found a postoperative improvement in the “psychological domain” (p = 0.041) and “social relationships” (p = 0.007), but a deterioration in “physical health” (p = 0.002) and “independence” (p = 0.031). Accordingly, deteriorations were seen in the areas of “energy” and “fatigue”, “sleep”, “negative feelings”, “mobility”, and “activities of daily living” (p <0.05). Castellano et al. (17) found after sex reassignment surgery for the group of trans women compared with the group of cis women no significant differences relating to “sexual activity” (65.85 vs 66.28; p >0.05), “body image” (64.64 vs 65.47; p >0.05), and the “quality of life score” (67.87 vs 69.49; p >0.05).
Quality of life and urinary incontinence
The King’s Health Questionnaire (KHQ) is a validated questionnaire for evaluating the impact of urinary incontinence on quality of life (33), a topic of central importance for trans persons (34). This questionnaire interrogates the quality of life domains always in association with urinary incontinence as the main problem. Kuhn et al. (19) showed that “general health” in trans persons was experienced as poorer to a relevant extent (Cohen’s d = 4.126; p = 0.019), and “physical” (d = −7.972; p <0.0001) and “personal limitations” (d = −7.016; p <0.001) were experienced to a greater extent. In contrast to this, trans persons felt less limited in terms of “role limitation” (d = 3.311; p = 0.046). For “emotions”, “sleep”, “incontinence”, and “symptom severity”, the differences to the control group did not reach significance. The control group consisted of cis women who had undergone abdominopelvic surgery. The evaluation of the visual analogue scale (VAS) showed a lower (d = 14.136; p <0.0001) degree of general life satisfaction in the group of trans persons.
The SHS (35), SWLS (36), and CLLS (37) are validated and internationally used visual analogue scales to evaluate life satisfaction. The SHS evaluates individual happiness and associated physical, mental, and social wellbeing (35). The SWLS was used as a short-form scale in the cited studies (also known as L-1) and included only the question on general life satisfaction (36). The CLLS evaluates emotional wellbeing associated with life satisfaction as well as subjective health (37).
Studies that used the SHS, SWLS, and CLLS (27, 28) to evaluate postoperative life satisfaction reported a high degree of “subjective happiness” (5.6; SD 1.4 and 5.9; SD 0.6), of “satisfaction with life“ (27.7; SD 5.8 and 27.1; SD 2.1) and “subjective wellbeing” (8.0 [range: 4–10] and 7.9; SD 0.7) in trans women after intestinal vaginoplasty. The studies cited earlier differ with regard to the following items: Bouman et al. (27) studied a population of young trans women (mean age: 19.1 years) with penoscrotal hypoplasia after primary laparoscopic intestinal vaginoplasty. The study participants had received puberty blockers during their transition therapy, which resulted in penoscrotal hypoplasia and made penile inversion vaginoplasty (Box) impossible. Van der Sluis et al. (28) studied an older population (mean age: 58 years) of trans women after secondary intestinal vaginoplasty—that is, patients who required secondary intestinal reconstruction owing to vaginal stenosis or insufficient vaginal length after penile inversion vaginoplasty. The postoperative follow-up period varied between 1–7.5 years (27) and 17.2–34.3 years (28). In spite of the different patient populations, these studies found that sex reassignment surgery had a positive effect on life satisfaction.
The FLZ is a validated multidimensional questionnaire for evaluating individual general life satisfaction (38). It is used in life quality and rehabilitation research and enables the recording of changes if administered repeatedly. It is available in a German language version only; for this reason, its results apply only to German speaking populations.
Studies that used the FLZ questionnaire (21, 29) found that the postoperative life satisfaction of trans women in terms of “health” does not differ from that of the general population. Additionally, Papadopoulos et al. (29) found no differences for “friends”, “hobbies”, “income”, “work”, and “relationship.” A subanalysis of the module “health” found postoperatively in both studies a relevant decrease in “fitness” (d = 0.521; p <0.001) and “energy” (d = 0.494; p <0.003). Zimmerman et al. (21) additionally found a significant decrease in “ability to relax/equilibrium” (p = 0.002), “fearlessness/absence of anxiety” (p = 0.015), and “absence of discomfort/pain” (p = 0.037). Both studies (21, 29) were retrospective surveys that were undertaken once only in a time period between 6 months and 58 months postoperatively. Papadopoulos et al. (29) included only subjects into the study who did not require any further corrective surgery after sex reassignment surgery or who had already undergone a second procedure for the purpose of minor corrections.
Two prospective studies documented postoperatively a notable improvement in quality of life (23, 26). Four studies found that the life quality of trans women after sex reassignment surgery was no different from that of cis women (17, 20, 22, 24). Sex reassignment surgery has also been shown to have a positive effect on life satisfaction (27, 28)—the exception was urinary incontinence, in which case life satisfaction dropped (19). Lindqvist et al. (23) and Weyers et al. (24) observed an improvement in self-perceived health in the first postoperative year, which then drops, albeit not all the way down to its original level. This is consistent with the honeymoon phase described by De Cuypere et al. (39), which has been described as a euphoric period in the first year after surgery. Several studies (18, 20–25) showed that physical pain increased after surgery and physical functioning deteriorated. This is easily explained by the surgery itself, however; the postoperative follow-up periods in these studies varied between 3 months (18) and 5 years (23).
Altogether the study results imply that sex reassignment surgery has an overall positive effect on partial aspects, such as mental health, sexuality, life satisfaction, and quality of life.
These results were confirmed by Barone et al. (40) and Murad et al. (15) in their review articles, which were published in 2017 and 2010, respectively. Barone et al. (40) in a systematic review evaluated patient reported results after sex reassignment surgery; among others, regarding life satisfaction. Murad et al. (15) in a meta-analysis focused on quality of life and psychosocial health after hormone therapy (main aspect) and sex reassignment surgery. In sum, both studies found improvements in quality of life and life satisfaction after sex reassignment surgery, and an improvement at the psychosocial level. Hess et al. (11) concluded that the study participants benefited from sex reassignment surgery—they too found high rates of satisfaction postoperatively in Germany.
As sex reassignment surgery often constitutes the final step of sex reassignment measures, hormone therapy as well as accompanying psychotherapy may have had a confounding effect. Not all studies adjusted for confounding factors. A lack of randomization and control or the use of a matched control group (17, 19) in the studies also introduced methodological bias (Table 2). Furthermore, the high dropout rates of 12% (17) to 77% (23) (median: 56%), which are mainly due to non-respondents, should be assessed critically. In our experience, however, the patient population of trans women is often reticent and is not interested in study participation because of personal reasons (“to not be reminded of that time”). Other authors have shared this observation (18, 24), which may also explain the occasionally high dropout rates. There is also the possibility that dissatisfied patients were among the dropouts. Owing to socioeconomic and clinical conditions, the studies from Croatia (18) and China (25) need to be evaluated separately. On the one hand, the authors of both studies draw attention to the public’s lack of awareness and understanding (and the associated psychological stress for trans women) in these countries, and, on the other hand, statutory sickness funds did not cover the costs of all treatments, which were therefore accessible to only few patients. This explains the notably lower participant numbers of 3 (18) and 4 (25) male-to-female transitions after sex reassignment surgery. None of the included studies reported potential suicide rates.
The strength of this review lies in the fact that we included only studies that used standardized questionnaires. Tests (such as the SF-36 or WHOQOL-100) represent validated and reliable measuring instruments, for some of which reference standard populations exist, and they enable international and intercultural comparison. Furthermore, standardized questionnaires have the advantage of a high degree of objectivity in terms of conducting, evaluating, and interpreting studies.
The available study data show that sex reassignment surgery has a positive effect on partial aspects—such as mental health/wellbeing, sexuality, and life satisfaction—as well as on quality of life overall.
It should be noted that the studies are almost exclusively retrospective analyses of mostly uncontrolled and small cohorts, for which no valid or specific measuring instruments are available to date. Because of the high dropout and non-response rates, the current data should be interpreted with caution.
In spite of the essentially positive results, the data are not satisfactory at this point in time. Due to the studies’ limited follow-up times, no conclusions can be drawn as yet about the long term consequences of such procedures. Furthermore, many studies did not use standardized questionnaires and/or scores, which makes comparisons between individual studies difficult.
Conflict of interest statement
The authors declare that no conflict of interest exists.
Manuscript received on 24 September 2018, revised version accepted on 11 February 2019.
Translated from the original German by Birte Twisselmann, PhD.
Klinik für Plastische Chirurgie und Handchirurgie
Rämistr. 100, CH-8091 Zürich
For eReferences please refer to:
ge=43812012 (last accessed on 20 October 2017).
Géraldine Weinforth, PD Dr. med. Richard Fakin, Prof. Dr. med. Pietro Giovanoli
Department of Plastic, Reconstructive & Aesthetic Surgery and Hand Surgery, Center for Gender Variance, Universitätsspital Basel: Dr. med. David Garcia Nuñez
|1.||Garcia Nuñez D, Nieder TO: Geschlechtsinkongruenz und -dysphorie. J Gynakol Endokrinol 2017; 15: 5–13.|
|2.||Meyer zu Hoberge S: Prävalenz, Inzidenz und Geschlechterverhältnis der Transsexualität anhand der bundesweit getroffenen Entscheidungen nach dem Transsexuellengesetz in der Zeit von 1991 bis 2000. www.macau.uni-kiel.de/receive/dissertation_diss_00004825?lang=de (last accessed on 20 September 2018).|
|3.||Falkai P: Diagnostische Kriterien DSM-5®. Göttingen: Hogrefe 2015.|
|4.||Hage JJ, Karim RB: Ought GIDNOS get nought? Treatment options for nontranssexual gender dysphoria. Plast Reconstr Surg 2000; 105: 1222–7 CrossRef|
|5.|| Coleman E, Bockting W, Botzer M, et al: Standards of Care – Versorgungsempfehlung für die Gesundheit von transsexuellen, transgender und geschlechtsnichtkonformen Personen. www.wpath.org/site_page.cfm?pk_association_webpage_menu=1351&pk_association_webpa|
ge=43812012 (last accessed on 20 October 2017).
|6.||Fisher AD, Maggi M: Endocrine treatment of transsexual male-to-female persons. In: Trombetta C, Liguori G, Bertolotto M: Management of gender dysphoria. Milano: Springer 2015; 86 CrossRef|
|7.||Canner JK, Harfouch O, Kodadek LM, et al.: Temporal trends in gender-affirming surgery among transgender patients in the united states. JAMA Surg 2018; 153: 609–16 CrossRef MEDLINE PubMed Central|
|8.||De Cuypere G, T‘Sjoen G, Beerten R, et al.: Sexual and physical health after sex reassignment surgery. Arch Sex Behav 2005; 34: 679–90 CrossRef MEDLINE|
|9.||Klein C, Gorzalka BB: Sexual functioning in transsexuals following hormone therapy and genital surgery: a review. J Sex Med 2009; 6: 2922–39; quiz 40–1 CrossRef MEDLINE|
|10.||Gijs L, Brewaeys A: Surgical treatment of gender dysphoria in adults and adolescents: recent developments, effectiveness, and challenges. Annu Rev Sex Res 2007; 18: 178–224.|
|11.||Hess J, Rossi Neto R, Panic L, Rübben H, Senf W: Satisfaction with male-to-female gender reassignment surgery—results of a retrospec-tive analysis. Dtsch Arztebl Int 2014; 111: 795–801 VOLLTEXT|
|12.||Bolton MA, Pruzinsky T, Cash TF, Persing JA: Measuring outcomes in plastic surgery: body image and quality of life in abdominoplasty patients. Plast Reconstr Surg 2003; 112: 619–25; discussion 26–7 CrossRef MEDLINE|
|13.||Sinno H, Dionisopoulos T, Slavin SA, Ibrahim AM, Chung KC, Lin SJ: The utility of outcome studies in plastic surgery. Plast Reconstr Surg Glob Open 2014; 2: e189 CrossRef MEDLINE PubMed Central|
|14.||White Hughto JM, Reisner S: A systematic review of the effects of hormone therapy on psychological functioning and quality of life in transgender individuals. Transgend Health 2016; 1: 21–31. CrossRef MEDLINE PubMed Central|
|15.||Murad M, Elamin M, Garcia M, et al.: Hormonal therapy and sex reassignment: a systematic review and meta-analysis of quality of life and psychosocial outcomes. Clin Endocrinol 2010; 72: 214–31 CrossRef MEDLINE|
|16.||Moher D, Liberati A, Tetzlaff J, Altman DG: Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. Ann Intern Med 2009; 151: 264–9 CrossRef|
|17.||Castellano E, Crespi C, Dell‘Aquila C, et al.: Quality of life and hormones after sex reassignment surgery. J Endocrinol Invest 2015; 38: 1373–81 CrossRef MEDLINE|
|18.||Jokic-Begic N, Korajlija A, Jurin T: Psychosocial adjustment to sex reassignment surgery: a qualitative examination and personal experiences of six transsexual persons in Croatia. Sci. World J 2014; 2014: 960745.|
|19.||Kuhn A, Bodmer C, Stadlmayr W, Kuhn P, Mueller MD, Birkhäuser M: Quality of life 15 years after sex reassignment surgery for transsexualism. Fertil Steril 2009; 92: 1685–9 CrossRef MEDLINE|
|20.||Parola N, Bonierbale M, Lemaire A, Aghababian V, Michel A, Lançon C: Study of quality of life for transsexuals after hormonal and surgical reassignment. J Sexol 2010; 19: 24–8 CrossRef|
|21.||Zimmermann A, Zimmer R, Kovacs L, et al.: Transsexuals‘ life satisfaction after gender transformation operations. Chirurg 2006; 77: 432–8 CrossRef MEDLINE|
|22.||Ainsworth TA, Spiegel JH: Quality of life of individuals with and without facial feminization surgery or gender reassignment surgery. Qual Life Res 2010; 19: 1019–24 CrossRef MEDLINE|
|23.||Lindqvist EK, Sigurjonsson H, Möllermark C, Rinder J, Farnebo F, Lundgren TK: Quality of life improves early after gender reassignment surgery in transgender women. Eur J Plast Surg 2017; 40: 223–6 CrossRef MEDLINE PubMed Central|
|24.||Weyers S, Elaut E, De Sutter P, et al.: Long-term assessment of the physical, mental, and sexual health among transsexual women. J Sex Med 2009; 6: 752–60 CrossRef MEDLINE|
|25.||Yang X, Zhao L, Wang L, et al.: Quality of life of transgender women from China and associated factors: a cross-sectional study. J Sex Med 2016; 13: 977–87 CrossRef MEDLINE|
|26.||Cardoso da Silva D, Schwarz K, Fontanari AM, et al.: WHOQOL-100 before and after sex reassignment surgery in brazilian male-to-female transsexual individuals. J Sex Med 2016; 13: 988–93 CrossRef MEDLINE|
|27.||Bouman MB, van der Sluis WB, van Woudenberg Hamstra LE, et al.: Patient-reported esthetic and functional outcomes of primary total laparoscopic intestinal vaginoplasty in transgender women with penoscrotal hypoplasia. J Sex Med 2016; 13: 1438–44 CrossRef MEDLINE|
|28.||van der Sluis WB, Bouman MB, de Boer NK, et al.: Long-term follow-up of transgender women after secondary intestinal vaginoplasty. J Sex Med 2016; 13: 702–10 CrossRef MEDLINE|
|29.||Papadopulos NA, Lellé JD, Zavlin D, et al.: Quality of life and patient satisfaction following male-to-female sex reassignment surgery. J Sex Med 2017: 721–30 CrossRef MEDLINE|
|30.||Morfeld M, Kirchberger I, Bullinger M: Fragebogen zum Gesundheitszustand (SF-36). Göttingen: Hogrefe 2011.|
|31.||Gunzelmann T, Brähler E, Angermeyer C, Kilian R, Matschinger H: Deutschsprachige Version der WHO Instrumente zur Erfassung von Lebensqualität WHOQOL-100 und WHOQOL-BREFM. Z med Psychol 2002; 44–8.|
|32.||Lehmann I: Procedures to measure quality of life. Z med Psychol 2007; 16: 5–23.|
|33.||Bjelic-Radisic V, Dorfer M, Tamussino K, et al.: Der King‘s Fragebogen zur Erfassung der Lebensqualität von Patientinnen mit Harninkontinenz (deutsche Version). Geburtshilfe Frauenheilkd 2005; 65: 1042–50 CrossRef|
|34.||Kuhn A, Hiltebrand R, Birkhauser M: Do transsexuals have micturition disorders? Eur J Obstet Gynecol Reprod Biol 2007; 131: 226–30 CrossRef MEDLINE|
|35.||Swami V, Stieger S, Voracek M, Dressler S, Eisma L, Furnham A: Psychometric evaluation of the tagalog and German Subjective Happiness Scales and a cross-cultural comparison. Soc Indic Res 2009; 93: 393 CrossRef|
|36.||Glaesmer H, Grande G, Braehler E, Roth M: The German version of the Satisfaction with Life Scale (SWLS): Psychometric properties, validity, and population-based norms. Eur J Psychol Assess 2011; 27: 127–32 CrossRef|
|37.||Levin K, Currie C: Reliability and validity of an adapted version of the Cantril Ladder for use with adolescent samples. Soc Indic Res 2014; 119: 1047 CrossRef|
|38.||Fahrenberg J, Myrtek M, Schuhmacher J, Brähler E: Fragebogen zur Lebenszufriedenheit (FLZ). Göttingen: Hogrefe 2000 MEDLINE|
|39.||De Cuypere G, Elaut E, Heylens G, et al.: Long-term follow-up: psychosocial outcome of Belgian transsexuals after sex reassignment surgery. Sexologies 2006; 15: 126–33 CrossRef|
|40.||Barone M, Cogliandro A, Di Stefano N, Tambone V, Persichetti P: |
A systematic review of patient-reported outcome measures following transsexual surgery. Aesthetic Plast Surg 2017; 41: 700–13 CrossRef MEDLINE
|e1.||Schardt C, Adams MB, Owens T, Keitz S, Fontelo P: Utilization of the PICO framework to improve searching PubMed for clinical questions. BMC Med Inform Decis Mak 2007; 7: 16 CrossRef MEDLINE PubMed Central|
|e2.||Oxford Uo. CEBM Levels of Evidence. 2011. www.cebm.net/wp-content/uploads/2014/06/CEBM-Levels-of-Evidence-2.1.pdf (last accessed on 25 November 2018).|
|e3.||Cochrane Deutschland, Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften – Institut für Medizinisches Wissensmanagement. „Bewertung des Biasrisikos (Risiko systematischer Fehler) in klinischen Studien: ein Manual für die Leitlinienerstellung“. 1st edition 2016. www.cochrane.de/de/rob-manual ; AWMF: www.awmf.org/leitlinien/awmf-regelwerk/ll-entwicklung.html (last accessed on 30 November 2018).|
Experiences and Interactions with the Healthcare System in Transgender and Non-Binary Patients in Austria: An Exploratory Cross-Sectional StudyInternational Journal of Environmental Research and Public Health, 202110.3390/ijerph18136895