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Discussion

Diagnosing and treating HIV infection

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Changes to the way the infection is diagnosed and treated have transformed HIV testing and care

In this article…

  • Testing for HIV in clinical and non-clinical settings
  • Prevalence and consequences of undiagnosed HIV
  • Different types of treatment and adherence to them
  • Prophylaxis and when it is recommended

Author

Martin Jones is clinical nurse specialist HIV, East Sussex Downs and Weald.

Abstract

Jones M (2011) Diagnosing and treating HIV infection. Nursing Times; 107: 11, early online publication.

In the past, HIV infection was regarded as synonymous with AIDS, but the condition is increasingly viewed as a long-term, treatable condition. This article identifies the main changes in diagnosing and treating HIV infection since testing was introduced in the UK 25 years ago.

Keywords: HIV, Sexual health, Opt-out testing, Clinical indicator diseases

  • This article has been double-blind peer reviewed

 

5 key points

1. HIV infection is increasingly viewed as a long term, treatable condition; however, it still carries a stigma

2. Late diagnosis is a significant reason for HIV-related morbidity and mortality, so there is interest in expanding access to testing

3. Opt-out testing has increased the uptake of voluntary HIV testing

4. Finger prick testing can be done in non-clinical settings; results are available in 20 minutes

5. HIV treatment requires high levels of concordance

 

FREE for one week: Identifying and Testing Patients for HIV Infection CPD unit

It is 25 years since a test for human immunodeficiency virus (HIV) was introduced in the UK. The test was introduced in the absence of effective anti-HIV treatment at a time of panic and prejudice, when the public perception was that being HIV positive was synonymous with having AIDS and would inevitably result in premature death. In this climate, healthcare professionals involved in HIV testing quickly recognised the need for supportive pre- and post-test counselling.

Since then, particularly in industrialised countries, HIV care has been transformed by the availability and use of highly active antiretroviral therapy (HAART). In the UK, HIV infection is increasingly viewed as a long-term, treatable condition with an increasing focus on long-term disease management and the effects of HIV infection on aging (British HIV Association, 2010). Consequently there has been a move away from pre-test counselling to opt-out testing with informed consent and post-test counselling for those who are diagnosed HIV positive and those at ongoing high risk of acquiring HIV. Testing is no longer exclusively the preserve of sexual health clinics. However, stigma associated with HIV infection persists and those involved in HIV testing must remain conscious of this.

Diagnosing HIV infection

HIV is diagnosed through a blood test. Current HIV testing kits combine antibody and antigen tests that identify infection with either of the two subtypes, HIV1 and HIV2. Testing is available as a conventional blood test, which is sent to a laboratory, or as a rapid test via finger-prick sampling. Improved sensitivity means that newly acquired HIV infection may be detected within a month of exposure - an improvement on the previous three-month window period (the time between acquiring HIV infection and a test being able to detect it) (British Association for Sexual Health and HIV, 2010). Saliva testing is also used in some situations, for example by insurance companies.

Late diagnosis

According to the Health Protection Agency, by the end of 2009 there were estimated to be 86,500 people living with HIV in the UK, of whom 27% (22,200) were unaware of their infection (HPA, 2010). One-third of those newly diagnosed with HIV in the UK has a CD4 count that is already below 200. CD4 cells are immune cells that can become infected with HIV; the normal range for CD4 cells is 500–1,600. BHIVA guidelines recommend starting highly active antiretroviral therapy when the CD4 count has fallen to 350 (BHIVA et al, 2008). There is a significant risk of developing AIDS-defining opportunistic infections when the CD4 count is below 200.

Late diagnosis is a significant cause of HIV-related morbidity and mortality. Since those with undiagnosed HIV infection cannot be targeted for interventions such as antiretroviral therapy, partner notification and post-exposure prophylaxis, there is considerable interest in reducing the proportion of undiagnosed HIV infection by expanding access to testing.

While HIV testing remains a backbone of sexual health care, testing has been a regular part of care in other settings - some for a considerable time. Blood and organ donors are routinely screened, as are organ recipients, and testing is essential when treating patients with conditions associated with HIV infection, such as tuberculosis, lymphoma, hepatitis B and hepatitis C (BHIVA et al, 2008).

Unlinked anonymous testing

Unlinked anonymous testing involves testing residual blood from sexual health and antenatal clinics for epidemiological surveillance. For example, testing residual blood after sexual health clinic testing reveals that 3.1% of men who have sex with men arrive at clinics with previously undiagnosed HIV. They may either be diagnosed at the corresponding clinic visit or leave without testing. This survey informs the estimate of undiagnosed HIV infections (HPA, 2010).

Opt-out testing

The most successful approach to increasing the uptake of voluntary HIV testing has been the switch to opt-out testing. Sexual health clinics now test 77% of their patients, with nurses gaining informed consent while performing other tests. Unless the patient declines, an HIV test is routinely performed alongside screening for other sexually transmitted infections such as chlamydia, gonorrhoea and syphilis. Patients at high risk or who require longer discussion are referred to a health adviser for a pre-test discussion. Similarly in antenatal care where HAART is available to prevent mother-to-child HIV transmission, 95% of pregnant women are now tested for HIV infection (HPA, 2010).

Extending HIV testing to general healthcare settings

The availability of effective treatment has increased the need for early diagnosis. With one-third of UK cases of HIV remaining undiagnosed the BHIVA and HPA recommend offering HIV testing to all adults registering at general practices or admitted to medical wards in areas where HIV prevalence is greater than 2 per 1,000 (BHIVA et al, 2008). Pilot studies, such as Heald (2010) have demonstrated the benefits to patients of testing for HIV in general medical settings.

Clinical indicator diseases

Clinical indicator diseases are conditions that are associated with HIV infection. It is recommended that all patients that present with these conditions should be tested for HIV infection (Table 1).

Non-clinical settings

New technology has produced new methods for diagnosing HIV. Finger-prick testing, with results available in 20 minutes, permits HIV testing in non-clinical settings and may attract patients who prefer rapid results to the traditional longer waiting time or who wish to avoid clinical settings. In a community-based pilot targeting men who have sex with men (MSM) in Brighton, men attending the community-based, rapid testing service were younger than those attending the local sexual health clinic and less likely to be HIV positive. Men in both groups were at similar, high risk of exposure to HIV infection (Bailey et al, 2009).

Current approaches to treatment of HIV infection

UK guidelines for treating adults with HIV are updated regularly by BHIVA (2008). There are similar guidelines for children (Children’s HIV Association, 2009). Outside specific, more complex scenarios, current practice is to offer HAART when the CD4 count falls to 350 and to start treatment as soon as the patient is ready.

BHIVA guidelines recommend a three-drug combination of antiretroviral agents from at least two different classes as first-line treatment (Box 1).

Box 1. First-line treatment recommendations

Truvada or Kivexa (fixed-dose tablets containing two nucleoside reverse transcriptase inhibitors) combined with a non-nucleoside reverse transcriptase inhibitor or a boosted protease inhibitor.

Source: British HIV Association (2008)

 

The recommended combination is Truvada or Kivexa (fixed-dose tablets containing two nucleoside reverse transcriptase inhibitors) combined with a non-nucleoside reverse transcriptase inhibitor or a boosted protease inhibitor.

There are more than 20 licensed drugs that treat HIV infection and recent years have seen the development of new drugs in new classes. Studies to determine the most beneficial strategies for prescribing these newer agents are underway. Similarly, there are studies comparing three-drug therapy with one-drug therapy (Medical Research Council, 2008).

Adherence

Patients’ readiness for treatment is essential as HAART demands high levels of adherence (Poppa et al, 2004)Adherence is difficult to measure and the precise level of required adherence varies from drug to drug. Guidelines currently recommend 95% to 100% adherence.

Fixed-dose tablets combining two or three antiretroviral agents have reduced the pill burden for patients, many of whom are able to take one tablet, once a day to treat their HIV infection. 

Post-exposure prophylaxis

Post-exposure prophylaxis (PEP) is a four-week course of HAART for those recently exposed to a high risk of acquiring HIV. Initially available to healthcare workers following sharps injury, it is now recommended for patients who present within 72 hours of high-risk sexual exposure (Table 2) (Fisher et al, 2006). Because of the benefits of early treatment, starter packs of PEP are available in accident and emergency departments. Patients starting PEP must be referred to a HIV specialist for assessment as soon as possible.

Conclusion

In the 25 years since HIV testing was introduced in the UK there have been considerable technological and therapeutic advances. We have the tools to manage HIV as a long-term condition, albeit one that requires particular knowledge and expertise. However, a significant proportion of those infected with HIV remain undiagnosed. Preventable morbidity and mortality associated with late diagnosis has led to recommendations for HIV testing beyond the traditional confines of the sexual health clinic. HIV testing should be every nurse’s and midwife’s concern. 

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