Effect of point-of-care CD4 cell count tests on retention of patients and rates of antiretroviral therapy initiation in sub-Saharan African countries: a systematic review protocol

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Abstract

Review question/objective

The objective of this review is to determine the effect of point of care CD4 cell count tests on retention of patients and rates of antiretroviral therapy initiation.

Background

The Human Immuno-deficiency Virus (HIV) pandemic continues to affect sub-Saharan Africa more than any other region in the world. One major barrier to tackling this pandemic is diagnosing the 90% of individuals in these countries who have not been tested for HIV infection. Rapid point-of-care (or near-patient) testing is increasingly being used in developing world settings to improve diagnosis of HIV infections.1,2,3,4,5

Background

Effective care and treatment for HIV and Acquired Immuno-Deficiency Syndrome (AIDS) requires the integration of all stages of disease management, which includes: (1) HIV testing; (2) referral of those who test HIV-positive to a clinic for assessment; (3) assessment of those patients with CD4 test to determine eligibility for antiretroviral therapy (ART) or pre-ART care; (4) patient enrolment and retention in pre-ART care if not immediately eligible for ART; (5) patient initiation of ART as soon as eligible; and (6) maintenance of long-term ART adherence.6

Background

Antiretroviral therapy is the recommended treatment for HIV infection. ART involves taking a combination of antiretroviral (ARV) HIV drugs (a regimen) daily. A regimen contains three or more ARV drugs from at least two different drug classes. ARV drugs prevent HIV from multiplying. ARV drugs keep people with HIV healthy, but they cannot cure HIV infection or prevent HIV transmission. In most developing countries, CD4 count is used as a criterion to determine eligibility for ART.7 In addition, it has been demonstrated that the use of the CD4 cell count criterion is superior to clinical staging in identifying clients eligible for ART.8 CD4 count is a laboratory test that measures the number of CD4 T lymphocytes (CD4 cells) in a sample of blood. In people with HIV, the CD4 count is the most important laboratory indicator of immune function and the strongest predictor of HIV progression.7 The World Health Organization (WHO) updated guideline on antiretroviral therapy for adults and adolescents, including pregnant women, now recommends that ART be initiated when CD4 cell counts reach or drop below 350 cells/mm3, regardless of whether or not patients have clinical symptoms.9 The CD4 count is also used to monitor response to ART.7

Background

Despite advances in the expansion of access to ART for HIV-positive patients in resource-limited settings, two-thirds of patients in need of treatment currently do not receive it.10

Background

Although worldwide funding for treatment in these settings has increased and the cost of delivery of ART has decreased, the financial sustainability of current coverage and the expansion of treatment to new patients are still concerns.11,12,13,14

Background

Accordingly, efforts to improve the efficiency and sustainability of ART are increasing.15,16 Low retention of patients undermines efforts to scale up ART.17,18,19,20,21 The existing limited evidence suggests that many patients fail to enroll in HIV care after referral from testing.2,22,23,25

Background

One solution proposed for the failure of many HIV Counseling and Testing (HCT) of clients to return for their CD4 test results is to integrate rapid, point of care testing (POCT) technologies, including point of care CD4 counting into HCT service sites.5 A point of care CD4 test is a CD4 test performed in the immediate vicinity of a patient to provide a rapid same-day result outside the conventional laboratory environment, in order to facilitate immediate clinical decision-making, including initiation and adjustment of anti-retroviral therapy.26 These technologies allow blood samples to be processed immediately, at the location where the HIV test is performed, so that a HCT client can receive CD4 count results on the same visit as the HIV test.6 In addition, they are characterized by being easy to use for non-laboratory personnel, highly automated with minimal manual steps, no requirement of precise sample measurement or manipulation, and results are easy to read. POC technologies do not require consistent electricity and refrigeration- the device can operate on battery power or an alternate power source. They utilize portable equipment that do not need manufacturer or specialized installation. Besides, they have a long shelf life for consumables (at least six months once consumables reach the facility, meaning they can be utilized at least for six months once they are delivered to health facilities). Furthermore, material wastes can be disposed off safely.26

Background

Rapid testing for HIV through various methodologies, using either blood or oral fluid samples, can give a result within 20 minutes with 97% to 100% sensitivity and specificity.5,27 Rapid point of care testing has the potential to allow post test counseling of those testing positive immediately after undergoing a test, which may increase the probability of patients returning for HIV specialist care, thus improving their health and reducing transmission.28

Background

The effect of point-of-care CD4 cell count tests on retention of patients and rates of ART initiation have been studied in some sub-Saharan African countries,14,15,17,18,29 For example, an observational study conducted in Mozambique indicated that point of care CD4 testing enabled clinics to stage patients rapidly on-site after enrolment.14 In addition, a South African pilot study indicated that patients offered point of care CD4 testing as part of the HCT services were more likely to visit a referral clinic after testing.17 Another South African randomized controlled trial indicated that the receipt of a CD4 count at the time of HIV testing increases ART initiation rates. The study concluded that point-of-care diagnostics can be used to improve retention.29 However, the findings of these studies, have not yet been synthesized in the form of a systematic review. Therefore, in this review, we will attempt to pool evidence regarding effect of point-of-care CD4 cell count tests on retention of patients and rates of ART initiation in sub-Saharan African countries.

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