REPRESENTATION AND EXTRAPOLATION: EVIDENCE FROM CLINICAL TRIALS.

This article examines the consequences and causes of low enrollment of Black patients in clinical trials. We develop a simple model of similarity-based extrapolation that predicts that evidence is more relevant for decision-making by physicians and patients when it is more representative of the group being treated. This generates the key result that the perceived benefit of a medicine for a group depends not only on the average benefit from a trial but also on the share of patients from that group who were enrolled in the trial. In survey experiments, we find that physicians who care for Black patients are more willing to prescribe drugs tested in representative samples, an effect substantial enough to close observed gaps in the prescribing rates of new medicines. Black patients update more on drug efficacy when the sample that the drug is tested on is more representative, reducing Black-white patient gaps in beliefs about whether the drug will work as described. Despite these benefits of representative data, our framework and evidence suggest that those who have benefited more from past medical breakthroughs are less costly to enroll in the present, leading to persistence in who is represented in the evidence base.

The NBER Orange Book Dataset: A user's guide.

This paper introduces a newly digitized, open-access version of the Food and Drug Administration's "Orange Book"-a linkage between approved small-molecule drugs and the patents that protect them. The Orange Book also reports any applicable regulatory exclusivity that prevents competitive entry. We summarize the Orange Book's coverage and discuss the opportunities and challenges associated with using these data for research. Empirical validations against various administrative datasets suggest that Orange Book records are, largely, complete and accurate. We conclude with a specific use case-calculating legal exclusivity periods for drugs-to highlight the types of choices that researchers must make when using this resource.

Enhancing Public Health Messaging: Discrete-Choice Experiment Evidence on the Design of HIV Testing Messages in China.

Introduction. While a growing literature documents the effectiveness of public health messaging on social media, our understanding of the factors that encourage individuals to engage with and share messages is limited. In the context of human immunodeficiency virus (HIV) among men who have sex with men (MSM) in China, rising incidence and low testing rates despite decades of interventions suggest the need for effective, targeted messaging to reach underserved populations. Social media platforms and sex-seeking apps present a promising avenue, as web-based strategies can take advantage of existing trust within dense social networks. Methods. We conducted an online discrete-choice experiment in January 2017 with MSM from across China. Participants were presented with 6 choice tasks, each composed of 2 messages about HIV testing, and were asked in which scenario they were more likely to share the content. Participants were given information about the source of the HIV testing message, the social media sharing platform, and the recipients with whom they would share the message. They were given the option of sharing 1 message or neither. Multinomial and mixed logit models were used to model preferences within 4 subgroups. Results. In total, 885 MSM joined the survey, completing 4387 choice tasks. The most important attribute for 3 of the 4 subgroups was social media sharing platform. Men were more willing to share messages on sex-seeking mobile applications and less willing to share materials on generic (non-MSM) social media platforms. We found that men with more active online presences were less willing to share HIV testing messages on generic social media platforms. Conclusions. Our findings suggest that sex-seeking platforms represent a targeted, efficient method of actively engaging MSM in public health interventions.

MSM Behavior Disclosure Networks and HIV Testing: An Egocentric Network Analysis Among MSM in China.

Men who have sex with men (MSM) disclose same-sex behaviors with others, creating disclosure networks. This study examined the characteristics of disclosure networks that are associated with HIV testing among MSM in China through an online nationwide survey. Name-generator questions were used to ask each participant ("ego") to nominate up to five social network members ("alters") with whom he had disclosed same-sex behaviors. Among the 806 men, the average disclosure network size was 4.05. MSM who reported larger disclosure networks were more likely to have been tested for HIV (aOR 1.21, 95% CI 1.08-1.34). The most common disclosure network alters were friends (45.1%), followed by sex partners (18.7%) and healthcare professionals (2.5%). Men who disclosed to healthcare professionals were more likely to test for HIV compared to men who disclosed to family members (aOR 5.43, 95% CI 2.11-14.04). Our findings can inform disclosure network-based interventions to promote MSM HIV testing.

No Place Like Home? Disentangling Preferences for HIV Testing Locations and Services Among Men Who Have Sex with Men in China.

In China, some health departments and gay community-based organizations have begun to offer home-based HIV testing kits in order to augment test uptake among men who have sex with men (MSM). However, HIV test preferences and motivations for home-testing among MSM in China are not well understood. The HIV testing preferences of 803 MSM throughout China were evaluated using single-item assessment and a discrete choice experiment (DCE). In both the single-item assessment and DCE, participants expressed strong preference for free and anonymous testing by health professionals. Both approaches also indicated that naïve testers most prefer home testing. However, among previous testers, the single-item assessment indicated that "home" was the most preferred testing location (vs. hospital or clinic), while the DCE indicated that "home" was the least preferred testing location after controlling for anonymity. HIV home-testing may have limited appeal to previously tested Chinese MSM if anonymity is not maintained.

Condom use peer norms and self-efficacy as mediators between community engagement and condom use among Chinese men who have sex with men.

BACKGROUND: Community engagement strategies are often integrated in public health interventions designed to promote condom use among men who have sex with men (MSM), a key population for HIV prevention. However, the ways in which condom use peer norms and self-efficacy play a role in the association between community engagement and condom use is unclear. This study examines the potential mediating roles of peer norms and self-efficacy in this association. METHODS: A nationwide cross-sectional online survey was conducted among Chinese MSM in 2015. Recruitment criteria included being born biologically male, being older than 16 years, having had anal sex with a man at least once during their lifetime, and having had condomless anal or vaginal sex in the past three months. Mplus 6.11 was used to conduct confirmatory factor analysis and path modeling analysis to examine the structural relationships between HIV/sexual health community engagement (e.g., joining social media and community events related to HIV and sexual health services), condom use peer norms, condom use self-efficacy, and frequency of condom use. RESULTS: The study found that HIV/sexual health community engagement, condom use peer norms, condom use self-efficacy, and frequency of condom use were mutually correlated. A good data model was achieved with fit index: CFI = 0.988, TLI = 0.987, RMSEA = 0.032, 90% CI (0.028, 0.036). HIV/sexual health community engagement was associated with frequency of condom use, which was directly mediated by condom use peer norms and indirectly through self-efficacy. CONCLUSION: The study suggests that condom use peer norms and self-efficacy may be mediators in the pathway between community engagement and condom use, and suggests the importance of peer-based interventions to improve condom use.

Social Media Engagement and HIV Testing Among Men Who Have Sex With Men in China: A Nationwide Cross-Sectional Survey.

BACKGROUND: Many interventions find that social media engagement with health promotion materials can translate into behavioral changes. However, only a few studies have examined the ways in which specific actions on various social media platforms are correlated with health behaviors. OBJECTIVE: The objective of this study was to examine the association between social media use and HIV testing behaviors among Chinese men who have sex with men (MSM). METHODS: In July 2016, a Web-based survey was conducted to recruit MSM in 8 Chinese cities through Blued (Blue City Holdings Ltd.), the world's largest gay mobile phone app. Data on sociodemographic variables, social media use platforms and behaviors, sexual behaviors, and HIV testing histories were collected. HIV testing-related social media use was defined as having ever engaged with HIV testing content on social media, which was further divided into observing (ie, receiving), endorsing (eg, liking and sharing), and contributing (eg, posting or commenting on HIV testing materials). Confirmatory factor analysis (CFA) was conducted to determine the best division of HIV testing-related social media use. Univariate and multivariable logistic regressions were used to examine the association between HIV testing-related social media use and HIV testing behaviors. RESULTS: A total of 2105 individuals participated in the survey. Among them, 46.75% (984) were under the age of 24 years, 35.43% (746) had high school education or less, and 47.74% (587) had condomless sex in the last 3 months. More than half of the respondents (58.14%, 1224/2105) reported HIV testing-related social media use. Additionally, HIV testing-related social media use, especially on multifunctional platforms such as WeChat, was found to be associated with recent HIV testing (adjusted odds ratio [aOR] 2.32, 95% CI 1.66-3.24). Contributing on social media was correlated with recent HIV testing (aOR 2.10, 95% CI 1.40-3.16), but neither observing (aOR 0.66, 95% CI 0.38-1.15) nor endorsing (aOR 1.29, 95% CI 0.88-1.90) were correlated. CONCLUSIONS: Our data suggest that social media use, particularly on multifunctional platforms such as WeChat and with contributing behaviors, is correlated with HIV testing among MSM in China. Campaigns that promote active participant contribution on social media beyond passive observation and endorsement of promotional materials are needed. This study has implications for the design and implementation of social media interventions to promote HIV testing.