January 17, 2014
Educational efforts play an essential role in helping to inform people about options for preventing the spread of sexually transmitted infections (STIs), including HIV. Information about STIs themselves -- signs, symptoms, the damage that they can cause, treatment options -- as well as regular screening for these infections and the correct and consistent use of condoms can all be helpful.
In the case of HIV, some clinical trials have found that taking a combination of anti-HIV drugs prior to possible exposure to the virus can reduce the risk of becoming infected. This approach is called Pre-Exposure Prophylaxis (PrEP). Also, in cases where someone is not taking PrEP and may have been exposed to HIV, taking a combination of anti-HIV drugs within 72 hours of exposure every day for 28 consecutive days can greatly reduce the risk of subsequently developing HIV infection. This approach is called Post-Exposure Prophylaxis (PEP).
The Infectious Diseases Society of America (IDSA) has an Emerging Infections Network (EIN). This group consists of infectious disease specialists who currently treat patients experiencing different infections. In the summer of 2013, the EIN surveyed doctors in Canada and the U.S. about their attitudes toward PrEP, how it was prescribed and perceived barriers to its use. In the U.S., the Food and Drug Administration (FDA) has approved the use of a combination of two anti-HIV drugs -- tenofovir + FTC, sold as a fixed-dose combination pill called Truvada -- for use in PrEP.
Researchers analysed responses to the EIN survey from 573 infectious disease specialists. Although a majority of specialists supported the use of PrEP, only 9% had prescribed it. Practices related to the prescription of PrEP and monitoring of patients on PrEP varied considerably. Clinicians reported many barriers to the use of PrEP outside of the well-resourced and controlled setting of a clinical trial.
In another study, Canadian researchers, led by infectious disease specialist Darrell Tan, M.D., Ph.D., surveyed a broader range of physicians in Canada about PrEP than the EIN. Their preliminary findings are somewhat similar to the results of the EIN survey.
In the EIN survey, out of the 1,175 infectious disease specialists who were surveyed, 573 (nearly 50%) responded. The physicians were distributed across the U.S. and 35% of respondents were from Canada (the geographic distribution within Canada was not provided).
In general, doctors who responded to the EIN survey about PrEP were more likely to be highly experienced clinicians compared to non-responders. The EIN has found this to be usually the case with respondents to its surveys. Please note that percentages do not add up to 100 because of rounding or in some cases because participants chose to respond to questions with more than one answer.
A majority of doctors (74%) supported the prescription of PrEP. However, only 9% of doctors had actually prescribed PrEP. Here are some of the reasons that doctors disclosed about not prescribing PrEP:
Additional reasons for not prescribing PrEP advanced by some doctors included the following (no percentages were provided):
Doctors who had prescribed PrEP or who were willing to prescribe PrEP were asked under what circumstances they would provide it. Answers to this question fell into two categories, as follows:
The main risk factor that would encourage doctors to provide PrEP was as follows:
Other situations that would prompt a prescription for PrEP included the following:
The EIN researchers stated that "a minority of respondents would provide PrEP to [people who injected street drugs]."
HIV screening most commonly involves testing blood or other bodily fluids for the presence of antibodies to HIV. However, in cases of early HIV infection, the immune system may take up to several weeks after exposure before producing antibodies. In such cases, screening blood for the genetic material of HIV (using assays called nucleic acid amplification tests, or NAAT) can sometimes uncover very early HIV infection.
The survey asked physicians about their potential use of nucleic acid testing (NAAT) and many disclosed that they would use NAAT to screen their patients for early HIV infection prior to prescribing PrEP and every three months while their patients were taking PrEP.
Taking medicines every day exactly as prescribed and directed is called adherence. This is essential if medicines are to achieve their full value, and in the case of PrEP, provide the greatest degree of protection.
There is no method for generally assessing adherence that is robust, fast, simple and cheap, so doctors often use different means of doing so. In the EIN survey, 81% of physicians responded that they would rely on their patients' self-reports for assessing adherence to PrEP. However, the EIN researchers caution that relying on patients to self-report adherence to PrEP may not be useful. This concern arises because in two studies of PrEP patient self-reports of adherence did not appear to be reliable. For instance, in one study called Voice, participants told researchers that they were 90% adherent yet only 30% had detectable levels of tenofovir in their blood. In another study called FEM-PrEP, 95% of participants reported taking PrEP exactly as directed but a much smaller proportion (between 25% and 33%) had detectable tenofovir in their blood.
Other responses from physicians about adherence monitoring included the following:
Most doctors would assess adherence every three months. However, 11% of physicians disclosed that they would not assess adherence.
Common reasons for physicians discontinuing providing PrEP were as follows:
According to the EIN researchers, physicians perceived many barriers to the use of and access to PrEP. In decreasing order of importance, here are the barriers mentioned by respondents:
Further commenting on perceived barriers, physicians made statements such as the following:
The researchers behind the EIN survey analysed the responses of doctors who had provided PrEP and compared them to responses of doctors who had not provided PrEP but stated that they were willing to do so in the future. The researchers found that doctors who provided PrEP were more willing to do the following:
An analysis of the geographic distribution of participants from the U.S. was done by researchers. Overall, there was no significant difference in locations of physicians who would or would not provide PrEP.
The U.S. Centers for Disease Control and Prevention (CDC) provides guidance and context for health care providers who are interested in the use of PrEP as part of a program to help prevent new HIV infections. However, despite the CDC's documents, the EIN researchers stated that "great variability exists in the real world practice of PrEP suggesting unawareness of, disagreement with or ambiguity of CDC guidance."
According to the EIN researchers, doctors displayed a "modest level of skepticism about the effectiveness of [PrEP in the real world]." Taking into account these and other concerns that the doctors raised when answering the survey, the EIN researchers stated that these concerns "may not be abated with increased [healthcare] provider education as has been recommended by previous studies ...." The researchers stated that a combination of the following might help to relieve the concern that some infectious disease specialists have about PrEP:
Based on the results they have received, the EIN researchers stated that their findings underscore the need for studies that can achieve several outcomes, including the following:
In 2012, researchers in Canada led by Dr. Darrell Tan surveyed a range of healthcare providers -- family physicians, infectious disease specialists, internal medicine specialists and public health nurses -- about PrEP.
Fifty-six participants completed their surveys. Nearly 57% identified themselves as HIV specialists and 51% felt "very familiar" with PrEP.
The Canadian survey found that nearly 43% of participants were willing to prescribe PrEP, while 52% stated that they were "unsure" about prescribing it, and 5% stated that they were not willing to do so.
Factors linked to a willingness to prescribe PrEP in Canada were as follows:
The Canadian study also found that doctors had similar concerns to participants in the larger EIN study, such as the following:
Although smaller than the EIN study, the Canadian study's findings are very likely robust, as they are similar to those of the larger study. Moreover, the Canadian study surveyed a broader range of healthcare providers.
Like its American counterpart, the Canadian study called for further research on PrEP in the real world, continuing medical education and clinical support for doctors. Also, both studies found that there are barriers to implementing PrEP and see further research as a way to help physicians get the data they need to prescribe PrEP with confidence.
Based on the data gleaned from the U.S. and Canadian studies, it seems that until the concerns of healthcare providers can be addressed, PrEP's use in the real world, at least in North America, may remain limited.
Pre-exposure prophylaxis (PrEP) -- CATIE fact sheet
ANRS IPERGAY trial -- Canadian HIV Trials Network