{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,17]],"date-time":"2026-10-17T20:48:16Z","timestamp":1792270096502,"version":"4.4.0"},"reference-count":41,"publisher":"CSIRO Publishing","issue":"3","license":[{"start":{"date-parts":[[2025,5,5]],"date-time":"2025-05-05T00:00:00Z","timestamp":1746403200000},"content-version":"vor","delay-in-days":2659,"URL":"https:\/\/doi.org\/10.1071\/journalslicense"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2018,6,4]]},"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Syphilis incidence worldwide has rebounded since 2000, particularly among men who have sex with men (MSM). A predictive model for syphilis infection may inform prevention counselling and use of chemoprophylaxis. Methods: Data from a longitudinal cohort study of MSM and transgender women meeting high-risk criteria for syphilis who were followed quarterly for 2 years were analysed. Incidence was defined as a four-fold increase in rapid plasma reagin (RPR) titres or new RPR reactivity if two prior titres were non-reactive. Generalised estimating equations were used to calculate rate ratios (RR) and develop a predictive model for 70% of the dataset, which was then validated in the remaining 30%. An online risk calculator for the prediction of future syphilis was also developed. Results: Among 361 participants, 22.0% were transgender women and 34.6% were HIV-infected at baseline. Syphilis incidence was 19.9 cases per 100-person years (95% confidence interval (CI) 16.3\u201324.3). HIV infection (RR 2.22; 95% CI 1.54\u20133.21) and history of syphilis infection (RR 2.23; 95% 1.62\u20133.64) were significantly associated with incident infection. The final predictive model for syphilis incidence in the next 3 months included HIV infection, history of syphilis, number of male sex partners and sex role for anal sex in the past 3 months, and had an area under the curve of 69%. The online syphilis risk calculator based on those results is available at: www.syphrisk.net. Conclusions: Using data from a longitudinal cohort study among a population at high risk for syphilis infection in Peru, we developed a predictive model and online risk calculator for future syphilis infection. The predictive model for future syphilis developed in this study has a moderate predictive accuracy and may serve as the foundation for future studies.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1071\/sh17118","type":"journal-article","created":{"date-parts":[[2018,1,22]],"date-time":"2018-01-22T20:06:23Z","timestamp":1516651583000},"page":"261-268","source":"Crossref","is-referenced-by-count":16,"title":["The development of an online risk calculator for the prediction of future syphilis among a high-risk cohort of men who have sex with men and transgender women in Lima, Peru"],"prefix":"10.1071","volume":"15","author":[{"given":"Lao-Tzu","family":"Allan-Blitz","sequence":"first","affiliation":[{"name":"ADivision of Infectious Diseases, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, 10833 Le Conte Ave, Los Angeles CA, 90095, USA."},{"name":"FCorresponding author. Email: lallanblitz@mednet.ucla.edu"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kelika A.","family":"Konda","sequence":"additional","affiliation":[{"name":"ADivision of Infectious Diseases, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, 10833 Le Conte Ave, Los Angeles CA, 90095, USA."},{"name":"BCentre for Interdisciplinary Studies in Sexuality, AIDS and Society, Cayetano Heredia University, Av. Honorio Delgado 430, San Mart\u00edn de Porres, 15102, Peru."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Silver K.","family":"Vargas","sequence":"additional","affiliation":[{"name":"BCentre for Interdisciplinary Studies in Sexuality, AIDS and Society, Cayetano Heredia University, Av. Honorio Delgado 430, San Mart\u00edn de Porres, 15102, Peru."},{"name":"CLaboratory of Sexual Health, Universidad Peruana Cayetano Heredia, Av. Honorio Delgado 430, San Mart\u00edn de Porres, 15102, Peru."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiaoyan","family":"Wang","sequence":"additional","affiliation":[{"name":"DDepartment of General Internal Medicine and Health Services Research, University of California Los Angeles, 911 Broxton Avenue, Los Angeles, CA, 90095, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eddy R.","family":"Segura","sequence":"additional","affiliation":[{"name":"ADivision of Infectious Diseases, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, 10833 Le Conte Ave, Los Angeles CA, 90095, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Boris M.","family":"Fazio","sequence":"additional","affiliation":[{"name":"BCentre for Interdisciplinary Studies in Sexuality, AIDS and Society, Cayetano Heredia University, Av. Honorio Delgado 430, San Mart\u00edn de Porres, 15102, Peru."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gino M.","family":"Calvo","sequence":"additional","affiliation":[{"name":"BCentre for Interdisciplinary Studies in Sexuality, AIDS and Society, Cayetano Heredia University, Av. Honorio Delgado 430, San Mart\u00edn de Porres, 15102, Peru."},{"name":"CLaboratory of Sexual Health, Universidad Peruana Cayetano Heredia, Av. Honorio Delgado 430, San Mart\u00edn de Porres, 15102, Peru."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Carlos F.","family":"Caceres","sequence":"additional","affiliation":[{"name":"BCentre for Interdisciplinary Studies in Sexuality, AIDS and Society, Cayetano Heredia University, Av. Honorio Delgado 430, San Mart\u00edn de Porres, 15102, Peru."},{"name":"CLaboratory of Sexual Health, Universidad Peruana Cayetano Heredia, Av. Honorio Delgado 430, San Mart\u00edn de Porres, 15102, Peru."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jeffrey D.","family":"Klausner","sequence":"additional","affiliation":[{"name":"ADivision of Infectious Diseases, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, 10833 Le Conte Ave, Los Angeles CA, 90095, USA."},{"name":"EDepartment of Epidemiology, Fielding School of Public Health, University of California Los Angeles, 650 Charles E Young Drive South, Los Angeles CA, 90095, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"67","published-online":{"date-parts":[[2018,1,23]]},"reference":[{"key":"2025102419070498200_R1","unstructured":"Centers for Disease Control and Prevention. Sexually transmitted disease surveillance 2015. Atlanta: U.S. Department of Health and Human Services; 2016. Available at: https:\/\/wwwcdcgov\/std\/stats15\/std-surveillance-2015-printpdf [verified 21 January 2017]."},{"issue":"3","key":"2025102419070498200_R2","doi-asserted-by":"publisher","first-page":"311","DOI":"10.1016\/0021-9681(55)90139-9","article-title":"The Oslo study of the natural history of untreated syphilis; an epidemiologic investigation based on a restudy of the Boeck-Bruusgaard material; a review and appraisal.","volume":"2","author":"Clark","year":"1955","journal-title":"J Chronic Dis"},{"issue":"7","key":"2025102419070498200_R3","doi-asserted-by":"publisher","first-page":"1020","DOI":"10.1093\/cid\/ciu450","article-title":"Syphilis predicts HIV incidence among men and transgender women who have sex with men in a preexposure prophylaxis trial.","volume":"59","author":"Solomon","year":"2014","journal-title":"Clin Infect Dis"},{"issue":"10","key":"2025102419070498200_R4","doi-asserted-by":"publisher","first-page":"1459","DOI":"10.1086\/508548","article-title":"Association of herpes simplex virus type 2 infection and syphilis with human immunodeficiency virus infection among men who have sex with men in Peru.","volume":"194","author":"Lama","year":"2006","journal-title":"J Infect Dis"},{"issue":"Suppl 1","key":"2025102419070498200_R5","doi-asserted-by":"publisher","first-page":"S47","DOI":"10.1097\/QAI.0b013e3181a2671d","article-title":"High HIV and ulcerative sexually transmitted infection incidence estimates among men who have sex with men in Peru: awaiting for an effective preventive intervention.","volume":"51","author":"Sanchez","year":"2009","journal-title":"J Acquir Immune Defic Syndr"},{"issue":"4","key":"2025102419070498200_R6","doi-asserted-by":"publisher","first-page":"e59072","DOI":"10.1371\/journal.pone.0059072","article-title":"Prevalence of HIV, STIs, and risk behaviors in a cross-sectional community- and clinic-based sample of men who have sex with men (MSM) in Lima, Peru.","volume":"8","author":"Perez-Brumer","year":"2013","journal-title":"PLoS One"},{"issue":"2","key":"2025102419070498200_R7","doi-asserted-by":"publisher","first-page":"75","DOI":"10.1097\/OLQ.0b013e3181c03434","article-title":"Recent syphilis infection prevalence and risk factors among male low-income populations in coastal Peruvian cities.","volume":"37","author":"Snowden","year":"2010","journal-title":"Sex Transm Dis"},{"issue":"Suppl 2","key":"2025102419070498200_R8","doi-asserted-by":"publisher","first-page":"S81","DOI":"10.1097\/01.aids.0000266460.56762.84","article-title":"Sexually transmitted disease and HIV prevalence and risk factors in concentrated and generalized HIV epidemic settings.","volume":"21","author":"NIMH Collaborative HIV\/STD Prevention Trial Group","year":"2007","journal-title":"AIDS"},{"issue":"10","key":"2025102419070498200_R9","doi-asserted-by":"publisher","first-page":"765","DOI":"10.1016\/S1473-3099(12)70144-5","article-title":"Prevalences of sexually transmitted infections in young adults and female sex workers in Peru: a national population-based survey.","volume":"12","author":"C\u00e1rcamo","year":"2012","journal-title":"Lancet Infect Dis"},{"issue":"9","key":"2025102419070498200_R10","doi-asserted-by":"publisher","first-page":"e0162156","DOI":"10.1371\/journal.pone.0162156","article-title":"Risk factors associated with incident syphilis in a cohort of high-risk men in Peru.","volume":"11","author":"Park","year":"2016","journal-title":"PLoS One"},{"issue":"6","key":"2025102419070498200_R11","doi-asserted-by":"publisher","first-page":"331","DOI":"10.1097\/OLQ.0b013e3181990c85","article-title":"Risk factors for repeat syphilis in men who have sex with men, San Francisco.","volume":"36","author":"Phipps","year":"2009","journal-title":"Sex Transm Dis"},{"issue":"1","key":"2025102419070498200_R12","doi-asserted-by":"publisher","first-page":"e1","DOI":"10.2105\/AJPH.2011.300383","article-title":"Repeat syphilis among men who have sex with men in California, 2002\u20132006: implications for syphilis elimination efforts.","volume":"102","author":"Cohen","year":"2012","journal-title":"Am J Public Health"},{"key":"2025102419070498200_R13","doi-asserted-by":"publisher","first-page":"75","DOI":"10.11604\/pamj.2016.24.75.8425","article-title":"A study on usefulness of a set of known risk factors in predicting maternal syphilis infections in three districts of Western Province, Zambia.","volume":"24","author":"Sakala","year":"2016","journal-title":"Pan Afr Med J"},{"issue":"5","key":"2025102419070498200_R14","doi-asserted-by":"publisher","first-page":"321","DOI":"10.1097\/OLQ.0000000000000120","article-title":"A critical appraisal of risk models for predicting sexually transmitted infections.","volume":"41","author":"Falasinnu","year":"2014","journal-title":"Sex Transm Dis"},{"key":"2025102419070498200_R15","doi-asserted-by":"publisher","first-page":"606","DOI":"10.1186\/1471-2458-13-606","article-title":"Screen more or screen more often? Using mathematical models to inform syphilis control strategies.","volume":"13","author":"Tuite","year":"2013","journal-title":"BMC Public Health"},{"issue":"2","key":"2025102419070498200_R16","doi-asserted-by":"publisher","first-page":"98","DOI":"10.1097\/OLQ.0000000000000216","article-title":"Doxycycline prophylaxis to reduce incident syphilis among HIV-infected men who have sex with men who continue to engage in high-risk sex: a randomized, controlled pilot study.","volume":"42","author":"Bolan","year":"2015","journal-title":"Sex Transm Dis"},{"key":"2025102419070498200_R17","doi-asserted-by":"publisher","first-page":"426","DOI":"10.1186\/1471-2334-13-426","article-title":"Characterizing the syphilis epidemic among men who have sex with men in Lima, Peru to identify new treatment and control strategies.","volume":"13","author":"Deiss","year":"2013","journal-title":"BMC Infect Dis"},{"issue":"1","key":"2025102419070498200_R18","doi-asserted-by":"publisher","first-page":"255","DOI":"10.1186\/s12879-017-2332-x","article-title":"The PICASSO cohort: baseline characteristics of a cohort of men who have sex with men and male-to-female transgender women at high risk for syphilis infection in Lima, Peru.","volume":"17","author":"Kojima","year":"2017","journal-title":"BMC Infect Dis"},{"issue":"6","key":"2025102419070498200_R19","doi-asserted-by":"publisher","first-page":"825","DOI":"10.1097\/QAD.0b013e32834380c1","article-title":"Mobile phone technologies improve adherence to antiretroviral treatment in a resource-limited setting: a randomized controlled trial of text message reminders.","volume":"25","author":"Pop-Eleches","year":"2011","journal-title":"AIDS"},{"key":"2025102419070498200_R20"},{"key":"2025102419070498200_R21","unstructured":"Ministry of Health. Peru: Health Technical Standard for the Management of Sexually Transmitted Infections In Peru. Lima. 2009. Available at: ftp:\/\/ftp2.minsa.gob.pe\/docconsulta\/documentos\/dgsp\/vihsida\/GuiaNacionalITS_Dic2006.pdf [verified 10 May 2017]"},{"issue":"3","key":"2025102419070498200_R22","doi-asserted-by":"publisher","first-page":"151","DOI":"10.1097\/01.olq.0000204506.06551.5f","article-title":"Syphilis treatment and HIV infection in a population-based study of persons at high risk for sexually transmitted disease\/HIV infection in Lima, Peru.","volume":"33","author":"Long","year":"2006","journal-title":"Sex Transm Dis"},{"issue":"6","key":"2025102419070498200_R23","doi-asserted-by":"publisher","first-page":"515","DOI":"10.7326\/0003-4819-130-6-199903160-00016","article-title":"Assessing the generalizability of prognostic information.","volume":"130","author":"Justice","year":"1999","journal-title":"Ann Intern Med"},{"issue":"2","key":"2025102419070498200_R24","first-page":"627","article-title":"Receiver operating characteristic (roc) curve analysis for medical diagnostic test evaluation.","volume":"4","author":"Hajian-Tilaki","year":"2013","journal-title":"Caspian J Intern Med"},{"issue":"1","key":"2025102419070498200_R25","doi-asserted-by":"publisher","first-page":"29","DOI":"10.1148\/radiology.143.1.7063747","article-title":"The meaning and use of the area under a receiver operating characteristic (ROC) curve.","volume":"143","author":"Hanley","year":"1982","journal-title":"Radiology"},{"issue":"45","key":"2025102419070498200_R26","doi-asserted-by":"publisher","first-page":"e2023","DOI":"10.1097\/MD.0000000000002023","article-title":"Serum TRSUT titer &gt;\/=1: 6 is a predictor for neurosyphilis among hiv-infected patients with concurrent syphilis and no neurological symptoms.","volume":"94","author":"Sun","year":"2015","journal-title":"Medicine (Baltimore)"},{"issue":"3","key":"2025102419070498200_R27","doi-asserted-by":"publisher","first-page":"736","DOI":"10.1128\/JCM.02522-13","article-title":"Comparison of the cerebrospinal fluid (CSF) toluidine red unheated serum test and the CSF rapid plasma reagin test with the CSF venereal disease research laboratory test for diagnosis of neurosyphilis among HIV-negative syphilis patients in China.","volume":"52","author":"Zhu","year":"2014","journal-title":"J Clin Microbiol"},{"issue":"12","key":"2025102419070498200_R28","doi-asserted-by":"publisher","first-page":"4060","DOI":"10.1128\/JCM.01989-13","article-title":"Clinical prediction and diagnosis of neurosyphilis in HIV-infected patients with early Syphilis.","volume":"51","author":"Dumaresq","year":"2013","journal-title":"J Clin Microbiol"},{"issue":"5","key":"2025102419070498200_R29","doi-asserted-by":"publisher","first-page":"374","DOI":"10.1136\/sextrans-2016-052870","article-title":"A double-edged sword: does highly active antiretroviral therapy contribute to syphilis incidence by impairing immunity to Treponema pallidum?","volume":"93","author":"Rekart","year":"2017","journal-title":"Sex Transm Infect"},{"issue":"1","key":"2025102419070498200_R30","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1097\/01.qai.0000214809.83218.88","article-title":"Adverse effects of antiretroviral drugs on HIV-1-infected and -uninfected human monocyte-derived macrophages.","volume":"42","author":"Azzam","year":"2006","journal-title":"J Acquir Immune Defic Syndr"},{"issue":"1","key":"2025102419070498200_R31","doi-asserted-by":"publisher","first-page":"39","DOI":"10.1016\/S0167-4889(97)00027-X","article-title":"2',3'-dideoxycytidine cytotoxicity in human macrophages.","volume":"1358","author":"Antonelli","year":"1997","journal-title":"Biochim biophys Acta"},{"issue":"2","key":"2025102419070498200_R32","doi-asserted-by":"publisher","first-page":"161","DOI":"10.3109\/08923979609052730","article-title":"In vitro effects of 3'-azido-3'-deoxythymidine (AZT) on normal human polymorphonuclear cell and monocyte-macrophage functional capacities.","volume":"18","author":"de Simone","year":"1996","journal-title":"Immunopharmacol Immunotoxicol"},{"key":"2025102419070498200_R33","first-page":"1","article-title":"Centers for Disease, Control and Prevention: sexually transmitted diseases treatment guidelines, 2015.","volume":"64","author":"Workowski","year":"2015","journal-title":"MMWR Recomm Rep"},{"issue":"5","key":"2025102419070498200_R34","doi-asserted-by":"crossref","first-page":"298","DOI":"10.1097\/OLQ.0b013e3181ca3c0a","article-title":"Frequent testing of highly sexually active gay men is required to control syphilis.","volume":"37","author":"Gray","year":"2010","journal-title":"Sex Transm Dis"},{"issue":"30","key":"2025102419070498200_R35","doi-asserted-by":"publisher","first-page":"e1242","DOI":"10.1097\/MD.0000000000001242","article-title":"Risk factors for acute and early HIV Infection Among Men Who Have Sex With Men (MSM) in San Diego, 2008 to 2014: a cohort study.","volume":"94","author":"Hoenigl","year":"2015","journal-title":"Medicine (Baltimore)"},{"issue":"5","key":"2025102419070498200_R36","doi-asserted-by":"publisher","first-page":"546","DOI":"10.1097\/QAI.0b013e318195bd2b","article-title":"Exploring the relationship between sexually transmitted diseases and HIV acquisition by using different study designs.","volume":"50","author":"Zetola","year":"2009","journal-title":"J Acquir Immune Defic Syndr"},{"issue":"1","key":"2025102419070498200_R37","doi-asserted-by":"publisher","first-page":"49","DOI":"10.1097\/OLQ.0000000000000535","article-title":"Are Centers for Disease Control and Prevention guidelines for preexposure prophylaxis specific enough? Formulation of a personalized HIV risk score for pre-exposure prophylaxis initiation.","volume":"44","author":"Beymer","year":"2017","journal-title":"Sex Transm Dis"},{"issue":"1","key":"2025102419070498200_R38","doi-asserted-by":"publisher","first-page":"e000005","DOI":"10.1136\/bmjopen-2010-000005","article-title":"Developing and validating a risk scoring tool for chlamydia infection among sexual health clinic attendees in Australia: a simple algorithm to identify those at high risk of chlamydia infection.","volume":"1","author":"Wand","year":"2011","journal-title":"BMJ Open"},{"issue":"1","key":"2025102419070498200_R39","doi-asserted-by":"publisher","first-page":"44","DOI":"10.1136\/sextrans-2015-052058","article-title":"Use of a risk quiz to predict infection for sexually transmitted infections: a retrospective analysis of acceptability and positivity.","volume":"92","author":"Gaydos","year":"2016","journal-title":"Sex Transm Infect"},{"issue":"4","key":"2025102419070498200_R40","doi-asserted-by":"publisher","first-page":"e40","DOI":"10.2196\/jmir.6.4.e40","article-title":"The effectiveness of web-based vs. non-web-based interventions: a meta-analysis of behavioral change outcomes.","volume":"6","author":"Wantland","year":"2004","journal-title":"J Med Internet Res"},{"issue":"10042","key":"2025102419070498200_R41","doi-asserted-by":"publisher","first-page":"412","DOI":"10.1016\/S0140-6736(16)00684-X","article-title":"Global health burden and needs of transgender populations: a review.","volume":"388","author":"Reisner","year":"2016","journal-title":"Lancet"}],"container-title":["Sexual Health"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/connectsci.au\/sh\/article-pdf\/15\/3\/261\/147076\/sh17118.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/connectsci.au\/sh\/article-pdf\/15\/3\/261\/147076\/sh17118.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,24]],"date-time":"2025-10-24T23:07:08Z","timestamp":1761347228000},"score":1,"resource":{"primary":{"URL":"https:\/\/connectsci.au\/sh\/article\/15\/3\/261\/21311\/The-development-of-an-online-risk-calculator-for"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,1,23]]},"references-count":41,"journal-issue":{"issue":"3","published-print":{"date-parts":[[2018,6,4]]}},"URL":"https:\/\/doi.org\/10.1071\/sh17118","relation":{},"ISSN":["1448-5028","1449-8987"],"issn-type":[{"value":"1448-5028","type":"print"},{"value":"1449-8987","type":"electronic"}],"subject":[],"published":{"date-parts":[[2018,1,23]]}}}