{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,10]],"date-time":"2026-10-10T14:12:57Z","timestamp":1791641577797,"version":"4.3.4"},"reference-count":42,"publisher":"Oxford University Press (OUP)","issue":"8","license":[{"start":{"date-parts":[[2021,2,22]],"date-time":"2021-02-22T00:00:00Z","timestamp":1613952000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/journals\/pages\/open_access\/funder_policies\/chorus\/standard_publication_model"}],"funder":[{"DOI":"10.13039\/100000025","name":"National Institute of Mental Health","doi-asserted-by":"publisher","award":["5F31 MH111346"],"award-info":[{"award-number":["5F31 MH111346"]}],"id":[{"id":"10.13039\/100000025","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"publisher","award":["AI064002 to RMG"],"award-info":[{"award-number":["AI064002 to RMG"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"publisher","award":["NCT00458393"],"award-info":[{"award-number":["NCT00458393"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2021,8,1]]},"abstract":"<jats:title>Abstract<\/jats:title>\n               <jats:p>Subgroup analyses of randomized controlled trials guide resource allocation and implementation of new interventions by identifying groups of individuals who are likely to benefit most from the intervention. Unfortunately, trial populations are rarely representative of the target populations of public health or clinical interest. Unless the relevant differences between trial and target populations are accounted for, subgroup results from trials might not reflect which groups in the target population will benefit most from the intervention. Transportability provides a rigorous framework for applying results derived in potentially highly selected study populations to external target populations. The method requires that researchers measure and adjust for all variables that 1) modify the effect of interest and 2) differ between the target and trial populations. To date, applications of transportability have focused on the external validity of overall study results and understanding within-trial heterogeneity; however, this approach has not yet been used for subgroup analyses of trials. Through an example from the Iniciativa Profilaxis Pre-Exposici\u00f3n (iPrEx) study (multiple countries, 2007\u20132010) of preexposure prophylaxis for human immunodeficiency virus, we illustrate how transporting subgroup analyses can produce target-specific subgroup effect estimates and numbers needed to treat. This approach could lead to more tailored and accurate guidance for resource allocation and cost-effectiveness analyses.<\/jats:p>","DOI":"10.1093\/aje\/kwab045","type":"journal-article","created":{"date-parts":[[2021,2,19]],"date-time":"2021-02-19T12:40:40Z","timestamp":1613738440000},"page":"1671-1680","source":"Crossref","is-referenced-by-count":17,"title":["Transporting Subgroup Analyses of Randomized Controlled Trials for Planning Implementation of New Interventions"],"prefix":"10.1093","volume":"190","author":[{"given":"Megha L","family":"Mehrotra","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Daniel","family":"Westreich","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"M Maria","family":"Glymour","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Elvin","family":"Geng","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"David V","family":"Glidden","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","published-online":{"date-parts":[[2021,2,22]]},"reference":[{"issue":"9454","key":"2021091506520140600_ref1","doi-asserted-by":"crossref","first-page":"176","DOI":"10.1016\/S0140-6736(05)17709-5","article-title":"Treating individuals 2. Subgroup analysis in randomised controlled trials: importance, indications, and interpretation","volume":"365","author":"Rothwell","year":"2005","journal-title":"Lancet"},{"issue":"10","key":"2021091506520140600_ref2","doi-asserted-by":"crossref","first-page":"680","DOI":"10.7326\/0003-4819-154-10-201105170-00008","article-title":"On the interpretation of subgroup analyses in randomized trials: heterogeneity versus secondary interventions","volume":"154","author":"VanderWeele","year":"2011","journal-title":"Ann Intern Med."},{"issue":"26","key":"2021091506520140600_ref3","doi-asserted-by":"crossref","first-page":"1728","DOI":"10.1056\/NEJM198806303182605","article-title":"An assessment of clinically useful measures of the consequences of treatment","volume":"318","author":"Laupacis","year":"1988","journal-title":"N Engl J Med"},{"issue":"6977","key":"2021091506520140600_ref4","doi-asserted-by":"crossref","first-page":"452","DOI":"10.1136\/bmj.310.6977.452","article-title":"The number needed to treat: a clinically useful measure of treatment effect","volume":"310","author":"Cook","year":"1995","journal-title":"BMJ"},{"issue":"27","key":"2021091506520140600_ref5","doi-asserted-by":"crossref","first-page":"2587","DOI":"10.1056\/NEJMoa1011205","article-title":"Preexposure chemoprophylaxis for HIV prevention in men who have sex with men","volume":"363","author":"Grant","year":"2010","journal-title":"N Engl J Med"},{"issue":"6","key":"2021091506520140600_ref6","doi-asserted-by":"crossref","first-page":"468","DOI":"10.1016\/S1473-3099(14)70025-8","article-title":"HIV pre-exposure prophylaxis in men who have sex with men and transgender women: a secondary analysis of a phase 3 randomised controlled efficacy trial","volume":"14","author":"Buchbinder","year":"2014","journal-title":"Lancet Infect Dis"},{"issue":"12","key":"2021091506520140600_ref7","doi-asserted-by":"crossref","first-page":"272","DOI":"10.14745\/ccdr.v43i12a05","article-title":"Setting the stage for expanding HIV pre-exposure prophylaxis use in Canada","volume":"43","author":"Hull","year":"2017","journal-title":"Can Commun Dis Rep"},{"issue":"4","key":"2021091506520140600_ref8","article-title":"Translating PrEP effectiveness into public health impact: key considerations for decision-makers on cost-effectiveness, price, regulatory issues, distributive justice and advocacy for access","volume":"18","author":"Hankins","year":"2015","journal-title":"J Int AIDS Soc"},{"key":"2021091506520140600_ref9","doi-asserted-by":"crossref","DOI":"10.1002\/jia2.25096","article-title":"The cost-effectiveness of HIV pre-exposure prophylaxis in men who have sex with men and transgender women at high risk of HIV infection in Brazil","author":"Luz","year":"2018"},{"issue":"2","key":"2021091506520140600_ref10","doi-asserted-by":"crossref","first-page":"438","DOI":"10.1093\/aje\/kwy228","article-title":"Target validity and the hierarchy of study designs","volume":"188","author":"Westreich","year":"2019","journal-title":"Am J Epidemiol"},{"key":"2021091506520140600_ref11","doi-asserted-by":"crossref","first-page":"495","DOI":"10.1186\/s13063-015-1023-4","article-title":"A literature review on the representativeness of randomized controlled trial samples and implications for the external validity of trial results","volume":"16","author":"Kennedy-Martin","year":"2015","journal-title":"Trials"},{"issue":"3","key":"2021091506520140600_ref12","doi-asserted-by":"crossref","first-page":"488","DOI":"10.1007\/s13187-013-0491-z","article-title":"The bottleneck effect in lung cancer clinical trials","volume":"28","author":"Gonzalez","year":"2013","journal-title":"J Cancer Educ"},{"issue":"7","key":"2021091506520140600_ref13","doi-asserted-by":"crossref","first-page":"1226","DOI":"10.1111\/add.13327","article-title":"Assessing sample representativeness in randomized controlled trials: application to the National Institute of Drug Abuse clinical trials network","volume":"111","author":"Susukida","year":"2016","journal-title":"Addiction"},{"issue":"1","key":"2021091506520140600_ref14","doi-asserted-by":"crossref","first-page":"306","DOI":"10.1186\/s13063-015-0812-0","article-title":"Similarities and differences between patients included and excluded from a randomized clinical trial of vitamin D supplementation for improving glucose tolerance in prediabetes: interpreting broader applicability","volume":"16","author":"Eisenberg","year":"2015","journal-title":"Trials"},{"issue":"9","key":"2021091506520140600_ref15","doi-asserted-by":"crossref","first-page":"e256","DOI":"10.2196\/jmir.6374","article-title":"The inclusion of ethnic minority patients and the role of language in telehealth trials for type 2 diabetes: a systematic review","volume":"18","author":"Isaacs","year":"2016","journal-title":"J Med Internet Res"},{"issue":"2","key":"2021091506520140600_ref16","doi-asserted-by":"crossref","first-page":"181","DOI":"10.1097\/QAI.0000000000000842","article-title":"A systematic review of the inclusion (or exclusion) of women in HIV research: from clinical studies of antiretrovirals and vaccines to cure strategies","volume":"71","author":"Curno","year":"2016","journal-title":"J Acquir Immune Defic Syndr"},{"issue":"4","key":"2021091506520140600_ref17","doi-asserted-by":"crossref","first-page":"579","DOI":"10.1214\/14-STS486","article-title":"External validity: from do-calculus to transportability across populations","volume":"29","author":"Pearl","year":"2014","journal-title":"Stat Sci"},{"key":"2021091506520140600_ref18","author":"Pearl","year":"2011"},{"issue":"1","key":"2021091506520140600_ref19","doi-asserted-by":"crossref","first-page":"107","DOI":"10.1093\/aje\/kwq084","article-title":"Generalizing evidence from randomized clinical trials to target populations: the ACTG 320 trial","volume":"172","author":"Cole","year":"2010","journal-title":"Am J Epidemiol Engl"},{"key":"2021091506520140600_ref20","volume-title":"Modern Epidemiology","author":"Rothman","year":"2008"},{"issue":"4","key":"2021091506520140600_ref21","doi-asserted-by":"crossref","first-page":"553","DOI":"10.1097\/EDE.0000000000000664","article-title":"Generalizing study results: a potential outcomes perspective","volume":"28","author":"Lesko","year":"2017","journal-title":"Epidemiology"},{"issue":"4","key":"2021091506520140600_ref22","doi-asserted-by":"crossref","first-page":"562","DOI":"10.1097\/EDE.0000000000000665","article-title":"\u201cAll generalizations are dangerous, even this one.\u201d\u2013Alexandre Dumas","volume":"28","author":"Balzer","year":"2017","journal-title":"Epidemiology"},{"issue":"5","key":"2021091506520140600_ref23","doi-asserted-by":"crossref","first-page":"1509","DOI":"10.1111\/rssb.12213","article-title":"Robust estimation of encouragement-design intervention effects transported across sites","volume":"79","author":"Rudolph","year":"2017","journal-title":"J R Stat Soc Ser B Stat Methodol"},{"issue":"2","key":"2021091506520140600_ref24","doi-asserted-by":"crossref","first-page":"199","DOI":"10.1097\/EDE.0000000000000774","article-title":"Composition or context: using transportability to understand drivers of site differences in a large-scale housing experiment","volume":"29","author":"Rudolph","year":"2018","journal-title":"Epidemiology"},{"issue":"3","key":"2021091506520140600_ref25","doi-asserted-by":"crossref","first-page":"e94","DOI":"10.1097\/QAI.0000000000002037","article-title":"Baseline characteristics explain differences in effectiveness of randomization to daily oral TDF\/FTC PrEP between transgender women and cisgender men who have sex with men in the iPrEx trial","volume":"81","author":"Mehrotra","year":"2019","journal-title":"J Acquir Immune Defic Syndr 1999"},{"issue":"9637","key":"2021091506520140600_ref26","doi-asserted-by":"crossref","first-page":"423","DOI":"10.1016\/S0140-6736(08)60883-1","article-title":"\u201cKnow your epidemic, know your response\u201d: a useful approach, if we get it right","volume":"372","author":"Wilson","year":"2008","journal-title":"Lancet"},{"issue":"6","key":"2021091506520140600_ref27","doi-asserted-by":"crossref","first-page":"1036","DOI":"10.2105\/AJPH.2006.102624","article-title":"HIV infection, sexual risk behavior, and substance use among Latino gay and bisexual men and transgender persons","volume":"98","author":"Ramirez-Valles","year":"2008","journal-title":"Am J Public Health"},{"key":"2021091506520140600_ref28","author":"Ramirez-Valles","year":"2014"},{"issue":"1","key":"2021091506520140600_ref29","doi-asserted-by":"crossref","first-page":"31","DOI":"10.1177\/0962280210386207","article-title":"Diagnosing and responding to violations in the positivity assumption","volume":"21","author":"Petersen","year":"2012","journal-title":"Stat Methods Med Res"},{"issue":"suppl 2","key":"2021091506520140600_ref30","doi-asserted-by":"crossref","first-page":"139S","DOI":"10.1016\/S0021-9681(87)80018-8","article-title":"A graphical approach to the identification and estimation of causal parameters in mortality studies with sustained exposure periods","volume":"40","author":"Robins","year":"1987","journal-title":"J Chronic Dis"},{"key":"2021091506520140600_ref31","volume-title":"Causality: Models, Reasoning, and Inference","author":"Pearl","year":"2000"},{"issue":"3","key":"2021091506520140600_ref32","doi-asserted-by":"crossref","first-page":"378","DOI":"10.1097\/EDE.0b013e3182126127","article-title":"Compound treatments, transportability, and the structural causal model: the power and simplicity of causal graphs","volume":"22","author":"Petersen","year":"2011","journal-title":"Epidemiology"},{"key":"2021091506520140600_ref33","volume-title":"Probabilistic Reasoning in Intelligent Systems: Networks of Plausible Inference","author":"Pearl","year":"1988"},{"issue":"1","key":"2021091506520140600_ref34","article-title":"Simple, efficient estimators of treatment effects in randomized trials using generalized linear models to leverage baseline variables","volume":"6","author":"Rosenblum","year":"2010","journal-title":"Int J Biostat Ger"},{"issue":"2","key":"2021091506520140600_ref35","doi-asserted-by":"crossref","first-page":"200","DOI":"10.1111\/j.1751-5823.2011.00138.x","article-title":"Connections between survey calibration estimators and semiparametric models for incomplete data","volume":"79","author":"Lumley","year":"2011","journal-title":"Int Stat Rev"},{"issue":"8","key":"2021091506520140600_ref36","doi-asserted-by":"crossref","first-page":"1010","DOI":"10.1093\/aje\/kwx164","article-title":"Transportability of trial results using inverse odds of sampling weights","volume":"186","author":"Westreich","year":"2017","journal-title":"Am J Epidemiol"},{"key":"2021091506520140600_ref37","doi-asserted-by":"crossref","DOI":"10.1007\/978-1-4899-4541-9","volume-title":"An Introduction to the Bootstrap","author":"Efron","year":"1993"},{"issue":"7223","key":"2021091506520140600_ref38","doi-asserted-by":"crossref","first-page":"1492","DOI":"10.1136\/bmj.319.7223.1492","article-title":"Calculating the number needed to treat for trials where the outcome is time to an event","volume":"319","author":"Altman","year":"1999","journal-title":"BMJ"},{"key":"2021091506520140600_ref39","volume-title":"R: A Language and Environment for Statistical Computing","author":"R Core Team","year":"2017"},{"key":"2021091506520140600_ref40","volume-title":"Stata Statistical Software: Release 15","author":"StataCorp","year":"2017"},{"key":"2021091506520140600_ref41","article-title":"Transport-subgroups","author":"Mehrotra","year":"2019"},{"issue":"14","key":"2021091506520140600_ref42","doi-asserted-by":"crossref","first-page":"1999","DOI":"10.1002\/sim.8426","article-title":"Extending inferences from a randomized trial to a new target population","volume":"39","author":"Dahabreh","year":"2020","journal-title":"Stat Med"}],"container-title":["American Journal of Epidemiology"],"original-title":[],"language":"en","link":[{"URL":"http:\/\/academic.oup.com\/aje\/advance-article-pdf\/doi\/10.1093\/aje\/kwab045\/38822897\/kwab045.pdf","content-type":"application\/pdf","content-version":"am","intended-application":"syndication"},{"URL":"http:\/\/academic.oup.com\/aje\/article-pdf\/190\/8\/1671\/40369921\/kwab045.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"http:\/\/academic.oup.com\/aje\/article-pdf\/190\/8\/1671\/40369921\/kwab045.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2021,9,15]],"date-time":"2021-09-15T06:55:37Z","timestamp":1631688937000},"score":1,"resource":{"primary":{"URL":"https:\/\/academic.oup.com\/aje\/article\/190\/8\/1671\/6145106"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,2,22]]},"references-count":42,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2021,2,22]]},"published-print":{"date-parts":[[2021,8,1]]}},"URL":"https:\/\/doi.org\/10.1093\/aje\/kwab045","relation":{},"ISSN":["0002-9262","1476-6256"],"issn-type":[{"value":"0002-9262","type":"print"},{"value":"1476-6256","type":"electronic"}],"subject":[],"published-other":{"date-parts":[[2021,8]]},"published":{"date-parts":[[2021,2,22]]}}}