An expanded national cohort study of transgender people - PROJECT SUMMARY/ABSTRACT
The goal of this proposal is to expand and extend the ongoing longitudinal Study of Transition, Outcomes &
Gender (STRONG), which is a cohort of transgender people identified from the electronic medical records of
three large integrated health care systems: Kaiser Permanente Georgia, Kaiser Permanente Southern
California, and Kaiser Permanente Northern California. The study now includes 6,459 members with an index
date (first evidence of transgender status) from 2006 through 2014. The transgender cohort is matched on
year of birth, race/ethnicity, site, and membership year at initial presentation (index date) with up to 10 male
and 10 female non-transgender enrollees. To-date cohort follow up extends through the end of 2016. The
STRONG cohort has already provided a number of new findings that will inform clinical practice. We found
that estrogen use is associated with several-fold increase in risk for venous thromboembolism and ischemic
stroke among transfeminine cohort members. We also found a much higher prevalence of psychiatric
polypharmacy and higher incidence of suicide attempts among transgender participants compared to matched
controls. Despite the importance of these results, many analyses were not feasible due to sparse treatment-
specific strata and the need for longer follow up. It is unclear if the observed associations can be explained by
a specific route of administration, dosage, or drug combinations. In addition, the STRONG cohort offers an
opportunity to characterize the distributions of a wide range of clinical health indicators and laboratory
measures among transgender people, which may help with the development of relevant reference ranges in
these population. In this application, we propose 1) including additional subjects at existing sites identified
through 2024, 2) adding a new site at Kaiser Permanente Mid-Atlantic States to increase geographic and
demographic diversity of the cohort, and 3) extending follow up through 2025. The final cohort will include as
many as 30,000 members matched to 600,000 referents. The methods of data collection described in the
current application have been successfully implemented previously. The new project will address three areas
of importance: 1) occurrence of acute cardiovascular events in relation to various aspects of hormone therapy;
2) changes in mental health status and incidence of suicide attempts among transgender people; and 3)
metabolic and hematologic consequences of cross-sex hormone therapy. The project will be carried out by a
team that includes experts in transgender health, electronic record-based data collection, s epidemiology and
specifically pharmacoepidemiology methods, advanced longitudinal data analyses, mental health,
cardiovascular disease, neuroscience and endocrinology.