[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-0-en-105":3,"doc-seo-402164-105":59,"doc-detail-402164-en":130},{"code":4,"msg":5,"data":6},0,"success",[7,13,18,23,28,33,38,43,48,51,55],{"id":8,"doc_module":4,"doc_module_name":9,"category_name":10,"show_sort_weight":11,"slug":12},1,"Document","Story & Novel",90,"story-novel",{"id":14,"doc_module":4,"doc_module_name":9,"category_name":15,"show_sort_weight":16,"slug":17},2,"Literature",80,"literature",{"id":19,"doc_module":4,"doc_module_name":9,"category_name":20,"show_sort_weight":21,"slug":22},4,"Exam",70,"exam",{"id":24,"doc_module":4,"doc_module_name":9,"category_name":25,"show_sort_weight":26,"slug":27},5,"Comic",60,"comic",{"id":29,"doc_module":4,"doc_module_name":9,"category_name":30,"show_sort_weight":31,"slug":32},6,"Technology",50,"technology",{"id":34,"doc_module":4,"doc_module_name":9,"category_name":35,"show_sort_weight":36,"slug":37},7,"Healthcare",40,"healthcare",{"id":39,"doc_module":4,"doc_module_name":9,"category_name":40,"show_sort_weight":41,"slug":42},8,"Research & Report",30,"research-report",{"id":44,"doc_module":4,"doc_module_name":9,"category_name":45,"show_sort_weight":46,"slug":47},9,"Religion & Spirituality",20,"religion-spirituality",{"id":46,"doc_module":4,"doc_module_name":9,"category_name":49,"show_sort_weight":46,"slug":50},"World Cup","world-cup",{"id":52,"doc_module":4,"doc_module_name":9,"category_name":53,"show_sort_weight":52,"slug":54},10,"Lifestyle","lifestyle",{"id":56,"doc_module":4,"doc_module_name":9,"category_name":57,"show_sort_weight":24,"slug":58},19,"General","general",{"code":4,"msg":60,"data":61},"ok",{"site_id":62,"language":63,"slug":64,"title":65,"keywords":66,"description":67,"schema_data":68,"social_meta":123,"head_meta":125,"extra_data":127,"updated_unix":129},105,"en","supplementary-methods-prep-surfing-study-supplementary-material","Supplementary Methods - PrEP surfing study supplementary material","","Supplementary material describes a study on PrEP surfing among HIV-negative men who have sex with men, focusing on how intention and recent practice were measured. Participants received an explanation of PrEP surfing and answered structured questions about using partners’ PrEP use to decide on condomless anal sex over the preceding six months and the upcoming six months. The supplement reports assessment of intention-behavior agreement using logistic regression and provides stratified distributions and adjusted odds ratios for related factors. It also summarizes construction of HIV-perception variables for regression analyses.",{"@graph":69,"@context":122},[70,84,105],{"@type":71,"itemListElement":72},"BreadcrumbList",[73,77,79,82],{"item":74,"name":75,"@type":76,"position":8},"https://docshare.wps.com","Home","ListItem",{"item":78,"name":9,"@type":76,"position":14},"https://docshare.wps.com/document/",{"item":80,"name":35,"@type":76,"position":81},"https://docshare.wps.com/document/healthcare/",3,{"item":83,"name":65,"@type":76,"position":19},"https://docshare.wps.com/document/supplementary-methods-prep-surfing-study-supplementary-material/402164/",{"url":83,"name":65,"@type":85,"image":86,"author":91,"headline":65,"publisher":94,"fileFormat":97,"inLanguage":63,"description":67,"dateModified":98,"datePublished":99,"encodingFormat":97,"isAccessibleForFree":100,"interactionStatistic":101},"DigitalDocument",{"url":87,"@type":88,"width":89,"height":90},"https://docshare.wps.com/thumbnails/supplementary-methods-prep-surfing-study-supplementary-material/402164.png","ImageObject",300,407,{"name":92,"@type":93},"percent12345","Person",{"url":74,"name":95,"@type":96},"DocShare","Organization","application/pdf","2026-10-29","2026-09-27",true,{"@type":102,"interactionType":103,"userInteractionCount":44},"InteractionCounter",{"@type":104},"ViewAction",{"@type":106,"mainEntity":107},"FAQPage",[108,114,118],{"name":109,"@type":110,"acceptedAnswer":111},"How were participants asked about recent PrEP surfing practice?","Question",{"text":112,"@type":113},"Participants were asked whether they used information about an HIV-negative casual partner’s PrEP use to decide on condomless anal sex in the preceding six months, with yes/no options.","Answer",{"name":115,"@type":110,"acceptedAnswer":116},"How was intention to PrEP surfing measured?",{"text":117,"@type":113},"Intention to use information about an HIV-negative partner’s PrEP use to decide on condomless anal sex in the coming six months was measured using a 7-point Likert scale with endpoints labeled as definitely not and definitely.",{"name":119,"@type":110,"acceptedAnswer":120},"Why might the number of participants differ between practice and intention analyses?",{"text":121,"@type":113},"The practice question was asked only to participants without HIV who reported no steady or casual partners, while the intention question was asked to all participants without HIV; therefore available data counts can differ.","https://schema.org",{"og:url":83,"og:type":124,"og:title":65,"og:site_name":95,"og:description":67},"article",{"robots":126,"canonical":83},"index,follow",{"doc_id":128,"site_id":62},402164,1790693841,{"code":4,"msg":5,"data":131},{"doc_id":128,"user_id":132,"nickname":92,"user_avatar":133,"doc_module":4,"category_id":34,"category_name":35,"doc_title":65,"doc_description":67,"doc_content":134,"file_id":135,"file_url":136,"file_type":137,"file_size":138,"view_count":44,"is_deleted":4,"is_public":8,"is_downloadable":8,"audit_status":8,"page_count":24,"language":139,"language_code":63,"site_id":62,"html_lang":63,"table_of_contents":140,"faqs":141,"seo_title":142,"seo_description":67,"update_tm":143,"read_time":144,"preview_page_count":4},1099529851338,"https://ap-avatar.wpscdn.com/davatar_155a257f0dc6eb9ab79c44ca47cae57d","Supplementary material to:  \nPrEP surfing: HIV preexposure prophylaxis use of sex partners as HIV prevention strategy among men who have sex with men  \nAuthors  \nCarien Blomaard1,2,3,4, Jeffrey C. D. Koole1, Elske Hoornenborg1,2,3,4, Maria Prins1,2,3,4, Janneke C. M. Heijne1,2,3,4, Udi Davidovich1,5, Maarten F. Schim van der Loeff1,2,3,4  \nAffiliations:  \n1. Department of Infectious Diseases, Public Health Service Amsterdam, Amsterdam, The Netherlands  \n2. Department of Internal Medicine, Amsterdam UMC location University of Amsterdam, Amsterdam, The  \nNetherlands  \n3. Amsterdam Institute for Immunology and Infectious Diseases (AII), Amsterdam, the Netherlands  \n4. Amsterdam Public Health Research Institute (APH), Amsterdam, the Netherlands  \n5. Department of Social Psychology, University of Amsterdam, Amsterdam, The Netherlands  \nSupplementary Methods  \nParticipants were asked to report recently practiced PrEP surfing and intention to PrEP surfing between  \nOctober 2021 and December 2023. First, they were provided a short explanation of PrEP surfing, and were asked questions about PrEP surfing as follows (please note that at the time we inserted these questions in the questionnaire we used the term “PrEP sorting” rather than “PrEP surfing”, but with identical meaning) : “The following questions are about PrEP sorting. PrEP is a medication that can be taken by HIV-negative individuals to reduce their risk of HIV infection. PrEP can be taken daily or intermittent (around the sex). When you use information about your partner’s PrEP use to decide to have condomless sex with them, we call it PrEP sorting.  \nPrEP sorting can be a way to protect yourself from HIV.  \nThen, the following question on recent PrEP surfing was posed:  \n1. “Did you use information about your HIV-negative casual partner’s PrEP-use in order to decide to have condomless anal sex with him, in the preceding six months?”  \nAnswer options: Yes/no  \nFinally, a question on intention to PrEP surfing in the coming 6 months was posed:  \n2. “Are you planning to use information about your HIV-negative partner’s PrEP-use in order to decide to  \nhave condomless anal sex with him, in the upcoming six months?”  \nAnswer options: Definitely not 1 2 3 4 5 6 7 Definitely  \nThe first question on recent practice of PrEP surfing was only asked to those without HIV reporting steady or  \ncasual partners; and the second question to all participants without HIV. Therefore, the number of participants with available data for recent PrEP surfing and intention to practice PrEP surfing may differ.  \nSupplementary Table 1. Assessment of intention-behavior agreement of PrEP surfing in past 6 months in 1,217 study visits among 475 HIV-negative men who have sex with men with event-driven or no PrEP use, participating in the Amsterdam Cohort Studies, the Netherlands, 2021-2023. Results from logistic regression with standard errors adjusting for correlated observations.  \n\n|  | Univariable model |  |  | Multivariable model |  |  |\n| --- | --- | --- | --- | --- | --- | --- |\n|  | median (IQR)/ n/N (%) | OR | 95% CI | aOR | 95% CI | p |\n| Intention to PrEP surfing in preceding visita | 4 (1-5) | 1.64 | 1.51-1.78 | 1.60 | 1.46-1.75 | \u003C0.001 |\n\nAge group  \n16-34 years  \n35-44 years  \n45-54 years  \n≥55 years Country of Origin  \nThe Netherlands  \nOther Steady partnerb  \nYes  \nNo  \nNumber of sex partnersb  \n0-2  \n3-8  \n≥9 PrEP useb, c  \nNo  \nYes  \nRectal STI or syphilisb  \nNo  \nYes  \nPerceived probability of contracting HIVd Low (1-2.5)  \n79/248 (31.9%)  \n77/241 (32 .0%)  \n81/431 (18 .8%)  \n57/297 (19.2%)  \n264/1,044 (25.3%) 27/164 (16.5%)  \n171/849 (20 . 1%)  \n123/368 (33.4%)  \n48/513 (9 .4%) 126/384 (32.8%)  \n120/320 (37.5%)  \n93/747 (12.5%) 201/470 (42.8%)  \n242/1,099 (22 .0%) 52/118 (44.1%)  \n238/1,037 (23.0%)  \nREF  \n1.00 0.50  \n0.51  \nREF  \n0.58  \nREF  \n1.99  \nREF  \n4.73  \n5.81  \nREF  \n5.25  \nREF  \n2.79  \nREF  \n-  \n0.63-1.61  \n0.32-0.77  \n0.30-0.85  \n-  \n0.35-0.98  \n-  \n1.42-2.78  \n-  \n3.07-7.30 ","cbCaimuTD9g9bQjf","https://ap.wps.com/l/cbCaimuTD9g9bQjf","pdf",309301,"English","# Supplementary Methods\n## PrEP surfing and intention questions\n## Participant eligibility for practice and intention measures\n## Supplementary Table 1: intention-behavior agreement\n## Supplementary Figure 1: HIV perception variable distributions","[{\"question\":\"How were participants asked about recent PrEP surfing practice?\",\"answer\":\"Participants were asked whether they used information about an HIV-negative casual partner’s PrEP use to decide on condomless anal sex in the preceding six months, with yes/no options.\"},{\"question\":\"How was intention to PrEP surfing measured?\",\"answer\":\"Intention to use information about an HIV-negative partner’s PrEP use to decide on condomless anal sex in the coming six months was measured using a 7-point Likert scale with endpoints labeled as definitely not and definitely.\"},{\"question\":\"Why might the number of participants differ between practice and intention analyses?\",\"answer\":\"The practice question was asked only to participants without HIV who reported no steady or casual partners, while the intention question was asked to all participants without HIV; therefore available data counts can differ.\"}]","Supplementary Methods - PrEP surfing study supplementary material | PDF",1790527659,13]