September 08, 2015
3 min read

No new infections among HIV PrEP clinical cohort

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The use of once-daily oral PrEP appeared effective among a cohort of patients enrolled within a large integrated health care system and resulted in no new cases of HIV infection, according to recent data.

Despite this positive outcome, acquisition of sexually transmitted infection was high, and self-reported condom use decreased after treatment initiation, the researchers wrote.

“Our study is the first to extend the understanding of the use of PrEP in a real-world setting and suggests that the treatment may prevent new HIV infections even in a high-risk setting,” researcher Jonathan E. Volk, MD, of Kaiser Permanente San Francisco Medical Center, said in a press release.

From July 2012 to February, Volk and colleagues examined the outcomes and behaviors of 1,045 high-risk patients referred for HIV PrEP within the Kaiser Permanente health care system. Patients were assessed for medical contraindications and interviewed on their reasons to initiate PrEP treatment before enrollment. Safety assessments and HIV/STI screening were repeated every 1 to 3 months after treatment initiation, and, after July 2014, patients were surveyed about changes in sexual behavior 6 months after starting PrEP through secure email.

Eighty percent of patients referred for PrEP initiated the treatment. The mean age of initiators was 37 years, with 99% identified as men who have sex with men. Patients who initiated PrEP were more likely than noninitiators to report multiple sex partners (84% vs. 69%; P < .001) and prior use of PrEP from an outside provider (7.8% vs. 0.7%; P = .002). Reasons against PrEP use reported by noninitiators included low risk for HIV (35%), cost concerns (15%) and an unwillingness to undergo required follow-up (10%).

During the 388 person-years of follow-up, there were no HIV diagnoses among patients who initiated PrEP (upper limit of one-sided 97.5% CI, 1%); however, 30% of PrEP users were diagnosed with an STI after 6 months of use (95% CI, 26%-35%), and 50% were diagnosed after 12 months of use (95% CI, 43%-56%). In addition, surveys completed by a subset of PrEP users (n = 143) 6 months after treatment initiation revealed a decrease in condom use among 41% of respondents, suggesting a potential increase in risky behavior.

“Our data suggest that fears about risk compensation resulting in increased HIV acquisition among PrEP users may be unfounded,” Volk and colleagues wrote. “High rates of STIs are concerning, however, and reinforce that ongoing screening and treatment for STIs, including hepatitis C, remain an essential component of PrEP delivery.”

Robert Grant

Robert M. Grant

In a related editorial, Robert M. Grant, MD, MPH, and Kimberly A. Koester, both of the University of California, San Francisco, wrote that the high rate of PrEP uptake within a primary care setting is extremely encouraging, but more work is required to identify and reduce the burden of STIs.

“Men who seek PrEP services tend to report more numbers of sexual partners and less condom use, so sexually transmitted infections are commonly present when PrEP is initiated,” they wrote. “PrEP is best combined with a parallel plan to prevent other STIs, which may include use of condoms, frequent testing and treatment, and discussion of STI test results with prospective partners.” – by Dave Muoio

Disclosures: Volk, Grant and Koester report no relevant financial disclosures. Please see the full study for a list of all other authors’ relevant financial disclosures.