Our review pooled data from 95,854 responses to highlight trends and disparities in PrEP use. Because this is a systematic review of published surveys, our estimated proportions cannot be generalized beyond the people who took the surveys; however, our findings may be important to be considered for future research and clinical practice.
CDC's national HIV behavioral surveillance system reported that 3.5% of MSM participants had taken ARVs before sex in the past 12 months in 2014. Our sample reported a higher rate (4.2%) than the behavioral surveillance estimates. The difference in estimates may be due to our review reporting lifetime use, whereas the CDC's behavioral surveillance study focused on PrEP use in the past 12 months. Moreover, our samples may not be representative of the key populations identified in the US national goals.
In this review, MSM and Hispanic/Latinos reported a higher PrEP use and faster growth rates than other key populations. Proportions of PrEP use among blacks and people in the Southern United States in recent years were similar, yet PrEP use among blacks improved significantly in the postguideline era, whereas people in the Southern United States were not much impacted by the guideline release. Moreover, PrEP use significantly increased among youth in the preguideline era; however, after the guideline release, growth stopped. Our review also found a 34% increase per year in the odds of lifetime PrEP use in the postguideline era and the odds of reporting PrEP use among MSM were twice as greater than among non-MSM.
We found very few studies for PWID. With the limited number of studies, PWID, especially non-MSM PWID, reported the lowest PrEP use compared with other key populations or non-MSM subgroups. Although clean injecting equipment can reduce the risk of HIV transmission, PWID are 22 times more likely to acquire HIV compared with the general population because of high levels of HIV risk behaviors (eg, sharing injection equipment with people with HIV), suggesting the importance of offering PrEP to this key population.[26,27] Further studies on identifying barriers and facilitators of PrEP prescription and use in PWID may help us understand this population's low PrEP use.
As noted previously, the proportion of PrEP use in youth demonstrated a significant growth in the preguideline era, whereas the growth was no longer significant in the postguideline era despite low PrEP use in this population. One reason for the low rate may be that TDF/emtricitabine was not approved for individuals younger than 18 years until May 2018. With the recent FDA approval, in addition to the CDC support document released in November 2018 for individuals aged 13 years and older, PrEP use in youth aged 13–24 years may significantly increase in the next few years.[28,29] A follow-up study assessing PrEP use in youth after the FDA approval may help us learn the impact of these FDA approvals and new guidance from the CDC.
Both blacks and people in the Southern United States reported similar proportions of PrEP use in recent years; however, the proportion did not demonstrate growth among people in the Southern United States, whereas PrEP use among blacks improved significantly in the postguideline era. This may show geographical disparities in PrEP access and availability. People in the Southern United States account for more than half of HIV diagnoses in the United States. To reduce the health care disparity because of geographical location, more studies are needed to identify barriers for PrEP use in this geographical area to understand and reduce barriers.
We identified only 4 studies that focused on women. Although 3 of these studies reported less than 1% of PrEP use among participating women, one recent study reported 2.4% of PrEP use in 2017, and the overall proportion of 0.8% was the lowest proportion among any of the populations described in this review. Moreover, black women comprised 59% of women diagnosed with HIV in 2017, whereas they represent 13.4% of women in the United States.;[31,32] however, our review found no studies that focused on PrEP use among black women. Black women are particularly vulnerable to HIV and in need of PrEP compared with other non-MSM populations but are neglected from PrEP studies. Further PrEP intervention studies focusing on or including women may be necessary to increase PrEP uptake in this population.
Heterogeneity remained high for some subgroups (eg, study years 2015–2017, people in the Southern United States, see Supplemental Table 2, Supplemental Digital Content, https://links.lww.com/QAI/B453). This might be due to the significant improvement in PrEP use over 3 years of the period. Also, heterogeneity tended to be high among people in the Southern United States, which may be due to the large geographic area of 17 states, with potential differences in other variables in each study location. Finally, this review included 19 studies with high risk of bias. These studies could potentially improve the scores (ie, reduce the risk of bias) by having recruited more participants from multiple locations.
This review has several other limitations. Participants may have been counted more than once in our review because they may have been included in more than one study sample, although we excluded studies with duplicated data sets. We cannot ignore that there are a limited number of studies (if any) in certain years for some key populations. Most included studies had high study quality with low risk of bias, but there may be other biases that were not assessed. Finally, a high heterogeneity of included studies is noteworthy; subgroup analyses reduced only some heterogeneity. Despite these limitations, this is the first review we know of to estimate proportions of PrEP use in key populations and geographic areas identified in the US national HIV prevention goals by synthesizing identified published self-reported surveys.
J Acquir Immune Defic Syndr. 2020;84(4):379-386. © 2020 Lippincott Williams & Wilkins