Results Summary

What was the research about?

People who are transgender have a gender identity that differs from the male or female sex assigned to them at birth. Some transgender people get gender-affirming therapies to change their bodies to match their gender identity. For example, they may take hormones such as estrogen or testosterone.

Gender-affirming therapies can improve mental health and quality of life for transgender adults. These improved outcomes may help transgender adults focus on other health concerns.

In this study, the research team wanted to learn if gender-affirming hormone therapy improved sexual health outcomes and symptoms of depression in transgender adults.

What were the results?

Compared with transgender patients who didn’t receive hormone therapy, those who did were less likely to have sexually transmitted infections and symptoms of depression.

Transgender adults who did and didn’t receive hormone therapy didn’t differ in:

  • Whether they filled a prescription for medicine to prevent HIV. HIV weakens the body's immune system and makes it hard for the body to fight off infections.
  • The amount of HIV in the blood being so low that a test can't detect it among patients with HIV.
  • New cases of HIV.

Who was in the study?

The study included health records for 6,330 transgender patients from 2016 to 2019. All received care at one of two clinics in Massachusetts and New York. In 2016, 86 percent took hormone therapy and 14 percent did not. Also, 7 percent of patients were living with HIV. Among patients, 63 percent were White, 20 percent Black, 8 percent were multiracial, 7 percent were Asian or Pacific Islander, and 2 percent identified as another race; 21 percent were Hispanic or Latinx. The average age was 28. Also, 47 percent were transgender female, 36 percent were transgender male, 16 percent were nonbinary, and 1 percent identified as another gender identity. In addition, 54 percent had private insurance, 42 percent had public insurance, and 4 percent didn’t have insurance.

What did the research team do?

The research team compared health records for transgender patients who did and didn’t receive hormone therapy over three years.

Transgender adults, researchers, and clinicians, such as doctors and nurses, helped design the study.

What were the limits of the study?

The study used records from two clinics that specialized in gender-affirming therapies. Results may differ for adults receiving care at other clinics. Most patients had public or private health insurance; results may differ for adults without health insurance.

Future research could include adults who seek care at clinics that don’t focus on gender-affirming therapies. It could also include more adults without health insurance.

How can people use the results?

Clinics can use the results when considering how to improve sexual health and mental health outcomes for transgender patients.

Peer-Review Summary

Peer review of PCORI-funded research helps make sure the report presents complete, balanced, and useful information about the research. It also assesses how the project addressed PCORI’s Methodology Standards. During peer review, experts read a draft report of the research and provide comments about the report. These experts may include a scientist focused on the research topic, a specialist in research methods, a patient or caregiver, and a healthcare professional. These reviewers cannot have conflicts of interest with the study. 

The peer reviewers point out where the draft report may need revision. For example, they may suggest ways to improve descriptions of the conduct of the study or to clarify the connection between results and conclusions. Sometimes, awardees revise their draft reports twice or more to address all of the reviewers’ comments.   

Peer reviewers commented and the researchers made changes or provided responses. Those comments and responses included the following: 

  • The reviewers agreed that this is a strong study and a useful report, but commented on challenges with its interpretation, because of the difference in scope of the original aim to characterize effects of gender affirmation (GA) hormone replacement therapy and GA surgical care and performed feasibility analyses (comparisons of GA hormone care versus none, and not GA surgical care). The researchers clarified in the report that in the original study protocol GA included hormones and surgeries, but only hormones were studied following a PCORI-approved study protocol modification due to unanticipated challenges in extracting surgery data from the electronic health record. Therefore, medical GA was defined as only including hormone care. 
  • The reviewers suggested that the researchers add more consistent explanations of the interventions and study comparators using lay language summaries of in the text. The researchers have expanded their description of what medical GA therapies are by adding a paragraph to the report’s Background section with a lay-language explanation. 
  • The reviewers questioned whether the heterogeneity of treatment effects (HTE) analyses were pre-specified or not, and asked details on the potential hypotheses underlying these analyses. The researchers explained that they had pre-specified these analyses and hypothesized that there would be no evidence of HTE by age, race, ethnicity or gender identity. 
  • The reviewers asked the researchers to expand their discussion of the possibility of uncontrolled confounding as a potential to explain findings in the observational cohort and rationales for seeking GA care. They cautioned the researchers against using causal language in their conclusions where findings could be explained by unknown factors. The researchers revised the report to reflect the potential of uncontrolled confounding to impact the association between medical GA and the study outcomes. They added a paragraph in the Discussion section summarizing challenges they encountered with uncontrolled confounding related to patient expectations about medical GA, as well as the temporal order of hormone therapy, patient-reported depression and anogenital sexually transmitted infections. 

Conflict of Interest Disclosures

Project Information

Sari L. Reisner, ScD
Brigham and Women's Hospital
Transgender Cohort Study of Gender Affirmation and HIV-related Health

Key Dates

November 2017
April 2023

Study Registration Information


Has Results
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Populations Populations PCORI is interested in research that seeks to better understand how different clinical and health system options work for different people. These populations are frequently studied in our portfolio or identified as being of interest by our stakeholders. View Glossary
Intervention Strategy Intervention Strategies PCORI funds comparative clinical effectiveness research (CER) studies that compare two or more options or approaches to health care, or that compare different ways of delivering or receiving care. View Glossary
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Last updated: March 14, 2024